JP2793750B2 - Photovoltaic element and power generation system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photovoltaic element and a power generation system, and more particularly to a pin structure made of a silicon-based non-single-crystal semiconductor material and a pn structure of microcrystalline silicon, polycrystalline silicon, or single crystal silicon. And a power generation system using the same.

[0002]

2. Description of the Related Art Conventionally, in a photovoltaic device having a pin structure made of a silicon-based non-single-crystal semiconductor material, an i-layer contains silicon atoms and germanium atoms or carbon atoms,
Various proposals have been made for a photovoltaic element having a changed band gap. For example, (1) “Optimum deposition c
conditions for a- (Si, Ge): H
using a triode-configura
ted rf glow discharge sys
tem ", JA Bragagnolo, P. Li
tlefield, A .; Mastrovito an
dG. Storti. Conf. Rec. 19th
IEEE Photovoltaic Special
sts Conference-1987 pp. 87
8, (2) “Efficiency improbe
ment in amorphous-SiGe: H
solar cells and itsapplic
ation to tandem type sola
r cells ", S. Yoshida, S. Yama
Naka, M .; Konagai and K.K. Taka
hashi, Conf. Rec. 19th IEEE
Photovoltaic Specialists
Conference-1987 pp. 1101,
(3) “Stability and terres
trial application of a-Si
tandem type solar cells "
A. Hiroe, H .; Yamagishi, H .; Ni
Shio, M .; Kondo and Y. Tawada
, Conf. Rec. 19th IEEE Photo
ovoltaic Specialists Conf
erence-1987 pp. 1111, (4)
“Preparation of high qual
ity a-SiGe: H Films and it
s application to the high
efficiency triple-juncti
on amorphos solar cells "
K. Sato, K .; Kawabata, S .; Tera
mono, H .; Sasaki, M .; Deguchi,
T. Itagaki, H .; Morikawa, M .; Ai
ga and K.S. Fujikawa, Conf. R
ec. 20th IEEE Photovoltaic
Specialists Conference-1
988 pp. 73, (5) USP 4,816,0
82 mag have been reported.

A theoretical study of the characteristics of a photovoltaic device in which the band gap is changed is described in, for example, (6) “A novel design for a
morphous silicon alloy so
lar cells "S. Guha, J. Yang,
A. Pawlikiewicz, T.W. Glatfelt
er, R .; Ross, and S.M. R. Ovshins
ky, Conf. Rec. 20th IEEE Pho
tovoltaic Specialists Con
reference-1988 pp. 79, (7) “N
umerial modeling of multi
junction amorphous silico
n based PI-N solar cells "
A. H. Pawlikiewicz and S.A. G
uha, Conf. Rec. 20th IEEE Ph
otovoltaicSpecialists Con
reference-1988 pp. 251 have been reported.

In such a conventional photovoltaic element, p
A layer having a changed band gap is inserted at the interface for the purpose of preventing recombination of photoexcited carriers near the / i, n / i interface, increasing the open-circuit voltage, and improving the hole carrier range. doing. Further, a photovoltaic element in which a pn junction formed on a polycrystalline silicon substrate and a pin junction formed of amorphous silicon are stacked has been reported. For example, (8) “Amorphous Si / Polycrys
talline SiStacked Solar C
el Have More More Than 12% C
overversion Efficiency "Koj
i. Okuda, Hiroaki. Okamoto a
nd Yoshihiro. Hamakawa, Ja
panese Journal of Physics
Vol. 22 No. 9 Sep. 1983 p
p. L605, (9) “Device Physic
s and Optimum Design of a
-Si / poly Si Tandem Solar
Cells "H. Takakura, K. Miyag
i, H .; Okamato, Y .; Hamakawa, P
rosedings of 4th Intenat
inal Photovoltaic Science
and Engineering Conferen
ce 1989 pp. 403 etc.

A photovoltaic element has been reported in which a doping layer is formed by laminating a layer containing a Group III element of the periodic table as a main constituent element and a layer containing silicon and carbon as main constituent elements. For example, (10) "Characterization of
δ-doped a-SiC p-Layer Pre
pared by Trimethylboronand
Triethylboron and its ap
application to Solar Cell
s ", K. Higuchi, K. Tabuchi,
S. yamanaka, M .; Konagai and
K. Takahashi, Proceedings
of 5th International Photo
ovoltaic Science and Engi
nearing Conference 1990, p
p529, (11) "High Efficiency
Amophoous Silicone Solar
Cells with Delta-Doped p
-Layer ", Y. Kazama, K. Seki,
W. Y. Kim. S. Yamanaka, M .; Kona
gai and K .; Takahashi, Japan
nice Journal of Applied P
physics Vol. 28, No. 7 July 1
989 pp. 1160-1164 (12) "Hig
h Efficiency Delta-Doped
Amophoous Silicone Solar
Cells Preparedby photoche
medical Vapor Deposition ”,
K. Higuchi, K .; Tabuchi, K .; S. L
im, M .; Konagai and K.K. Takaha
shi, Japanese Journal A
Applied Physics Vol. 30, no.
8 August 1991 pp. 1635-164
0, (13) "High Efficiency Am
ouphoous Silicone Solar Ce
lls with Delta-Doped p-La
yer ", A. Shibata, Y. Kazama,
K. Seki, W.C. Y. Kim. S. Yamanak
a, M. Konagai and K.K. Takahas
hi, Conf. Rec. 20th IEEE Pho
tovoltaicSpecialists Conf
erence-1988 pp. 317. Etc.

[0006]

The conventional photovoltaic device containing silicon and carbon atoms and having a changed band gap has a further problem of recombination of photoexcited carriers, open-circuit voltage, and carrier range of holes. Improvement is desired. In addition, long wavelength sensitivity of 800 nm or more is poor, and further improvement is desired.

[0007] The above photovoltaic element has a problem that the photoelectric conversion efficiency is reduced when the photovoltaic element is irradiated with light. Furthermore, there is a problem that if the i-type layer has strain and is annealed where there is vibration or the like, the photoelectric conversion efficiency decreases. On the other hand, in the conventional pin / pn stacked photovoltaic device, the open voltage is small, the conversion efficiency is reduced when the photovoltaic device is irradiated with light, and annealing is performed where there is vibration or the like. In addition, there is a problem that the photoelectric conversion efficiency is reduced.

An object of the present invention is to provide a photovoltaic element which solves the above-mentioned conventional problems. That is, an object of the present invention is to provide a photovoltaic element in which recombination of photoexcited carriers is prevented, and an open voltage and a carrier range of holes are improved. It is another object of the present invention to provide a photovoltaic element in which conversion efficiency is less likely to decrease when light is irradiated to the photovoltaic element.

It is a further object of the present invention to provide a photovoltaic element in which the photoelectric conversion efficiency is unlikely to decrease when annealing is performed under vibration for a long period of time. It is a further object of the present invention to provide a photovoltaic element having improved short-wavelength sensitivity and long-wavelength sensitivity and an improved short-circuit current. Still another object of the present invention is to provide a system using a photovoltaic device which has achieved the above-mentioned object.

[0010]

Means for Solving the Problems In order to solve the above problems and achieve the object of the present invention, the inventors of the present invention have made intensive studies and found that the photovoltaic element of the present invention is polycrystalline. A first p-type layer made of microcrystalline silicon, polycrystalline silicon, or single-crystal silicon, an n-type layer made of a non-single-crystal semiconductor material, a non-monolayer, I made of crystalline semiconductor material
In a photovoltaic device in which a p-type layer and a second p-type layer made of a non-single-crystal semiconductor material are sequentially stacked, the i-type layer contains at least silicon atoms and carbon atoms, and the i-type layer The band gap changes in the thickness direction, and the i-type layer is doped with a valence electron controlling agent serving as a donor and a valence electron controlling agent serving as an acceptor , and the i-type layer and the p-type layer and / or the n-type layer are doped. A content of the valence electron controlling agent in the vicinity of the interface with the i-type layer is larger than that in the i-type layer.

Alternatively, a first n-type layer made of microcrystalline silicon, polycrystalline silicon, or single-crystal silicon, or a non-single-crystal semiconductor material is formed on a p-type substrate made of polycrystalline silicon or single-crystal silicon. In a photovoltaic element in which a p-type layer made of a non-single-crystal semiconductor material and a second n-type layer made of a non-single-crystal semiconductor material are sequentially stacked, the i-type layer has at least silicon atoms. The i-type layer is doped with a valence electron controlling agent serving as a donor and a valence electron controlling agent serving as an acceptor. A photovoltaic element, wherein the photovoltaic element changes in the i-type layer.

In a preferred embodiment of the photovoltaic device of the present invention, a photovoltaic device having a Si layer made of a non-single-crystal silicon-based material between the i-type layer and the second p-type layer or the p-type layer. It is a power element. As a desirable mode of the photovoltaic device of the present invention, at least one of both ends in the layer thickness direction of the i-type layer has a maximum value of the band gap of the i-type layer, and a region of the maximum value of the band gap. Is 1 to 30 nm
Within the photovoltaic element.

According to another preferred embodiment of the photovoltaic device of the present invention, the second p-type layer, the n-type layer, the first p-type layer (or the second n-type layer, the p-type Layer, the first n
At least one of the layers includes silicon and at least one element selected from carbon, oxygen, and nitrogen, and serves as a valence electron controlling agent, a group III element or a group III element in the periodic table. A layer containing a group V element or a group VI element (layer A) and a layer containing a group III element, a group V element, or a group VI element of the periodic table as a main constituent element (B
) Is a photovoltaic element having a laminated structure.

In a preferred embodiment of the photovoltaic device of the present invention, the i-type layer contains both a valence electron controlling agent as a donor and a valence electron controlling agent as an acceptor. Further, the valence electron controlling agent serving as the donor is a Group V element or / Group VI element of the periodic table, and the valence electron controlling agent serving as the acceptor is a Group III element of the periodic table. Is more preferably distributed in the layer thickness direction.

A preferred embodiment of the photovoltaic device of the present invention is a photovoltaic device in which the Si layer contains a Group V element and / or a Group VI element of the periodic table. Further, a desirable mode of the photovoltaic element of the present invention
A photovoltaic element in which the i-layer contains a Group III element of the periodic table and a Group V element and / or a Group VI element of the Periodic Table.

In addition, a preferred embodiment of the photovoltaic device of the present invention is a photovoltaic device in which the i-type layer contains oxygen atoms and / or nitrogen atoms. In addition, as a desirable mode of the photovoltaic device of the present invention, the above-mentioned i
This is a photovoltaic device in which the hydrogen content contained in the mold layer changes according to the silicon atom content.

In addition, a desirable mode of the photovoltaic element of the present invention is that the i-type layer has an internal pressure of 50 mTorr or less and the microwave energy required to decompose 100% of the source gas for depositing a deposited film. A photovoltaic element formed by applying microwave energy to the source gas and simultaneously applying RF energy higher than the microwave energy to the source gas, wherein the Si layer has an RF
It is formed by a plasma CVD method and has a deposition rate of 2 nm.
/ Sec or less and a photovoltaic element formed with a layer thickness of 30 nm or less.

A system using the photovoltaic device according to the present invention comprises the above-described photovoltaic device, and monitoring the voltage and / or current of the photovoltaic device to supply the photovoltaic power to a storage battery and / or an external load. It is characterized by comprising a control system for controlling the supply of electric power from the element, and a storage battery for accumulating electric power from the photovoltaic element and / or supplying electric power to an external load.

[0019]

The operation and structure of the present invention will be described below in detail with reference to the drawings. FIG. 1A and FIG. 1B are schematic explanatory diagrams of the photovoltaic device of the present invention. 1A, the photovoltaic element of the present invention includes a back electrode 101, an n-type silicon substrate 102, a first p-type layer 103, and an n-type layer 10.
4, Si layer 105, i-type layer 106, second p-type layer 10
7, a transparent electrode 108, a current collecting electrode 109, and the like. The interface between the n-type silicon substrate and the first p-type layer is “p / substrate interface”, the interface between the first p-type layer and the n-type layer is “n / p interface”, and the interface between the n-type layer and the Si layer is The interface is referred to as “Si / n interface”, the interface between the Si layer and the i-type layer is referred to as “i / Si interface”, and the interface between the i-type layer and the second p-type layer is referred to as “p / i interface”.

Similarly, in FIG. 1B, the photovoltaic element of the present invention includes a back electrode 121, a p-type silicon substrate 122,
First n-type layer 123, p-type layer 124, i-type layer 125, S
It comprises an i-layer 126, a second n-type layer 127, a transparent electrode 128, a current collecting electrode 129, and the like. Also, the interface between the p-type silicon substrate and the first n-type layer is “n / substrate interface”, the interface between the first n-type layer and the p-type layer is “p / n interface”,
The interface between the p-type layer and the i-type layer is referred to as “i / p interface”, and the i-type layer and the Si
The interface between the layers will be referred to as “Si / i interface”, and the interface between the Si layer and the second n-type layer will be referred to as “n / Si interface”.

FIG. 19 shows the photovoltaic device of FIG. 1A having a second Si layer between the i-type layer and the p-type layer. In the present invention, since the position of the band gap minimum value of the i-type layer is offset toward the second p-type layer (p-type layer), the vicinity of the p / i interface (i / p interface) of the i-type layer. The electric field in the conduction band is large, so that electrons and holes can be efficiently separated, and recombination of electrons and holes can be reduced.
Further, back diffusion of the conduction electrons into the second p-type layer (p-type layer) is suppressed. In the i-type layer, i / S
As the electric field of the valence band increases toward the i interface (Si / i interface), the i / Si interface (Si / i interface) increases.
Recombination of electrons and holes photo-excited in the vicinity of the interface can be reduced, improving the photoelectric conversion efficiency, and further reducing the photoelectric conversion efficiency by irradiating the photovoltaic element with light for a long time ( Light degradation) can be suppressed.

Further, by adding both a valence electron controlling agent serving as a donor and a valence electron controlling agent serving as an acceptor to the i-type layer, the carrier range of electrons and holes can be extended. Especially where the carbon content is at the maximum
By adding a relatively large amount of the valence electron controlling agent, the carrier range of electrons and holes can be effectively lengthened. As a result, the i / Si interface (Si / i interface)
A high electric field in the vicinity and a high electric field in the vicinity of the p / i interface (i / p interface) can be more effectively used, and the collection efficiency of electrons and holes excited in the i-type layer can be significantly improved. be able to. In addition, defect levels (so-called D ⁻ and D ⁺ ) near the i / Si interface (Si / i interface) and near the p / i interface (i / p interface) are compensated for by the valence electron controlling agent, so that the defects are reduced. Dark current (during reverse bias) due to hopping conduction through the level is reduced. In particular, in the vicinity of the interface, the internal stress such as strain caused by a sudden change of the constituent element peculiar to the interface can be reduced by including a larger amount of the valence electron controlling agent than in the i-type layer. Thereby, the defect level near the interface can be reduced.

As a result, the open voltage and the fill factor of the photovoltaic element can be improved. In addition, by including both a valence electron controlling agent serving as a donor and a valence electron controlling agent serving as an acceptor inside the i-type layer, the durability against light degradation is increased. Although the details of the mechanism are unknown, it is generally considered that the dangling bonds generated by light irradiation become recombination centers of carriers and deteriorate the characteristics of the photovoltaic element. In the case of the present invention, both the valence electron controlling agent serving as a donor and the valence electron controlling agent serving as an acceptor are contained in the i-type layer.
0% not activated. As a result, even if dangling bonds are generated by light irradiation, it is considered that they react with the inactive valence electron controlling agent to compensate for dangling bonds.

In addition , even when the light intensity applied to the photovoltaic element is low , the photoexcited electrons and holes are trapped because the defect levels are compensated by the valence electron controlling agent. the probability that is Ru is is reduced. Further , as described above, since the dark current at the time of reverse bias is small, a sufficient electromotive force can be generated. As a result, excellent photoelectric conversion efficiency is exhibited even when the intensity of light applied to the optical storage element is low.

In addition, the photovoltaic device of the present invention is one in which the photoelectric conversion efficiency does not easily decrease even when annealing is performed under vibration for a long period of time. Although the detailed mechanism is unknown, the photovoltaic element is formed by changing the constituent elements in order to continuously change the band gap. Therefore, strain is accumulated inside the photovoltaic element. That is, many weak couplings exist inside the photovoltaic element. Then, the weak bond in the i-type layer is broken by vibration, and an unbonded bond is formed. This is because adding a valence electron controlling agent as a donor and a valence electron controlling agent as an acceptor together increases local flexibility, and the photoelectric conversion efficiency of the photovoltaic element even during annealing due to long-term vibration. Is considered to be able to suppress the decrease in

In the Si layer, defect levels (so-called D
^-, D ⁺⁾ is by being compensated by the valence control agent added to the Si layer, when the dark current (reverse bias due to hopping conduction via the defect level) decreases. In particular, i / S
In the Si layer near the i interface (Si / i interface) or near the Si / n interface (n / Si interface), the valence electron controlling agent is contained in a larger amount than the central region of the Si layer. Defect levels in the vicinity of the interface can be reduced due to a sudden change in constituent elements peculiar to the vicinity, or to a reduction in internal stress caused by stopping plasma. As a result, the open voltage and the fill factor of the photovoltaic element can be improved.

Further, by stacking a pin structure made of a non-single-crystal silicon-based semiconductor material on a pn structure made of a microcrystalline, polycrystalline, or single-crystal silicon semiconductor layer, a short-wavelength light and a long-wavelength light can be prevented. Sensitivity is improved, short-circuit current is improved, and open-circuit voltage is further improved. Further, the n (p) -type layer formed of a non-single-crystal material formed on the pn junction can easily be formed by using a microcrystalline silicon, a polycrystalline silicon, or a single-crystal silicon semiconductor material. Since crystallization can be performed, the open-circuit voltage can be improved.

Further, on the upper Symbol fine crystallized n (p) type layer, by laminating Si layer (or i-type layer)
The packing density of the Si layer (or i-type layer) is increased, and a decrease in photoelectric conversion efficiency (light deterioration) particularly when light is irradiated for a long time can be reduced. A decrease in photoelectric conversion efficiency can be suppressed.

Further, before forming the p (n) type layer on the substrate, the substrate is subjected to hydrogen annealing at 300 ° C. to 900 ° C.
Alternatively, a hydrogen plasma treatment can be used to bond hydrogen atoms to defects at the crystal grain boundaries to compensate for the defects, and atoms in the vicinity of the crystal grain boundaries can be relaxed to reduce the defect level. This improves the photoelectric conversion efficiency. In addition, the contact surface of the metal electrode of the pn laminated structure and pi
The contact surface of the n-structure can obtain more current and electromotive force by providing the degenerated semiconductor layer.

After the formation of the pn structure, the substrate temperature 1
When a pin structure is formed at a temperature of 50 ° C. to 400 ° C., active hydrogen atoms are formed, which act on defects in the bulk and crystal grain boundaries of the pn structure. The atoms in the vicinity of the grain boundaries are relaxed and the defect level can be reduced, and the photoelectric conversion efficiency of the photovoltaic element is improved. This means that the i-type layer is
This is particularly noticeable when formed by the method D.

In the photovoltaic device of the present invention, the Si layer is deposited at a deposition rate of 2 nm /
It is preferable that the layer be formed in seconds or less and have a thickness of 30 nm or less. Thereby, the photoelectric conversion efficiency of the photovoltaic element can be further improved. In particular, the photovoltaic element of the present invention has a small change in photoelectric conversion efficiency when used in an environment with a large temperature change.

The Si layer deposited by the RF plasma CVD method is deposited at a low power at a deposition rate of 2 nm / sec or less and in which a gas phase reaction hardly occurs. As a result, the packing density of the deposited film is high and the i / Si interface (Si / i
The interface state at the interface) is reduced, and therefore, the open voltage and the fill factor of the photovoltaic element can be improved. This is particularly noticeable when the i-type layer is deposited by microwave plasma CVD.

In the photovoltaic element having the layer structure shown in FIG. 1A, the vicinity of the i / Si interface of the i-type layer immediately after the start of the deposition is the above-mentioned deposition film having a low deposition rate with an underlayer formed by RF plasma CVD. Therefore, the interface state of the i-type layer can be reduced under the influence of the underlayer, and the open voltage and the fill factor of the photovoltaic element can be improved. This is particularly noticeable when the i-type layer is formed by the microwave plasma CVD method of the present invention.

In the photovoltaic device having the layer configuration shown in FIG. 1B, the surface level near the surface of the i-type layer immediately after the end of the deposition is not sufficiently relaxed, so that it is considered that the surface level is very large. By forming a deposition film having a low deposition rate on the surface of such an i-type layer by the RF plasma CVD method, the surface level of the i-type layer is changed by the diffusion of hydrogen atoms occurring simultaneously with the formation of the deposition film by the RF plasma CVD. This can be reduced by annealing, and the open voltage and the fill factor of the photovoltaic element can be improved. This remarkably appears when the i-type layer is formed by the microwave plasma CVD method.

The desirable form of the photovoltaic device of the present invention is as follows:
This is a photovoltaic element in which an i-type layer is sandwiched between Si layers as shown in FIG. In addition, when the Si layer contains a valence electron controlling agent (Group V element and / or Group VI element) serving as a donor, the n-type layer (second n-type layer) and the i-type layer Since the internal stress such as strain due to the rapid change of the constituent elements between the two can be reduced, the i / Si interface (Si
/ I interface) or the defect level of the Si layer near the Si / n interface (n / Si interface). As a result, the open voltage and the fill factor of the photovoltaic element can be improved.

In addition, a valence electron controlling agent (Group III element in the periodic table) serving as an acceptor and a valence electron controlling agent (Group V element and / or Group VI element) in the Si layer serve as a donor. By containing it, the durability against light degradation is increased. Although the details of the mechanism are unknown, it is generally considered that the dangling bonds generated by light irradiation become recombination centers of carriers and deteriorate the characteristics of the photovoltaic element. In the case of the present invention, both the valence electron controlling agent serving as a donor and the valence electron controlling agent serving as an acceptor are contained in the Si layer, and they are not 100% activated. As a result, even if dangling bonds are generated by light irradiation, it is considered that they react with the inactive valence electron controlling agent to compensate for dangling bonds.

In addition , even when the light intensity applied to the photovoltaic element is low , the photoexcited electrons and holes are trapped because the defect level is compensated by the valence electron controlling agent. the probability that is Ru is is reduced. Further , as described above, since the dark current at the time of reverse bias is small, a sufficient electromotive force can be generated. As a result, it shows a photoelectric conversion efficiency of the irradiation light intensity is superior can have you when weak to photovoltaic element.

In addition, the photovoltaic element of the present invention is one in which the photoelectric conversion efficiency does not easily decrease even when annealing is performed under vibration for a long time. Although the detailed mechanism is unknown, the i / Si interface (S
In the vicinity of the (i / i interface), by adding both a valence electron controlling agent serving as a donor and a valence electron controlling agent serving as an acceptor, local flexibility is increased. It is considered that the decrease in the photoelectric conversion efficiency of can be suppressed.

FIGS. 2A and 2B show changes in the band gaps of the i-type layer and the Si layer of the photovoltaic device according to the present invention, and are の of the band gap (Eg / 2). It is based on. Fig. 2-1 shows RF plasma CVD
I-type layer 211 having a Si layer 212 formed by
Is smaller than the center position by p / i
It is near the interface (i / p interface) and the maximum position of the band gap is between the i / Si interface (Si / i interface) and p / i.
It is configured to be in contact with the interface (i / p interface). In FIG. 2B, as in FIG. 2A, the Si layer 2 formed by the RF plasma CVD method is used.
22, the minimum position of the band gap of the i-type layer 221 is closer to the p / i interface (i / p interface) than the center position, and the maximum value of the band gap is the p / i interface (i / p interface). (Interface). FIG.
By using a band gap configuration such as -2,
In particular, the open-circuit voltage can be increased.

FIGS. 3-1 to 3-7 show the vicinity of the i / Si interface (Si / i interface) and / or the p / i interface (i / i interface).
FIG. 9 is a schematic explanatory diagram of a change in band gap of a photovoltaic element having a region with a constant band gap in an i-type layer near a (p interface). Each figure depicts a change in band gap based on Eg / 2. The left side of the band diagram is the i / Si interface (Si / i interface), and the right side is the p / i interface (i / p interface). is there.

FIG. 3A shows that 313 is a Si layer and p / i
In the i-type layer near the interface (i / p interface), there is a region 312 having a constant band gap, and the band gap is i / p.
This is an example having a region 311 that decreases from the Si interface (Si / i interface) side toward the p / i interface (i / p interface). The minimum value of the band gap is at the interface between the region 312 and the region 311. In addition, the bonding of the bands between the region 311 and the region 312 is such that the bands are discontinuously connected. By providing such a region having a constant band gap, dark current due to hopping conduction via a defect level at the time of reverse bias of the photovoltaic element can be suppressed as much as possible. As a result, the open-circuit voltage of the photovoltaic element increases. The layer thickness of the region 312 having a constant band gap is a very important factor, and a preferable range of the layer thickness is 1 to 30 nm. If the layer thickness in the region where the band gap is constant is smaller than 1 nm, dark current due to hopping conduction via defect levels cannot be suppressed, and improvement in the open-circuit voltage of the photovoltaic element cannot be expected. On the other hand, the region 31 where the band gap is constant
If the layer thickness of layer 2 is greater than 30 nm, photoexcited holes tend to accumulate near the interface between the constant bandgap region 312 and the bandgap changing region 311, so that photoexcited carriers are collected. Efficiency is reduced. That is, the short-circuit photocurrent is reduced.

FIG. 3B shows the p / i interface (i / p) of the i-type layer.
A region 322 having a constant band gap in the i-type layer near the interface)
And a region 321 where the band gap changes.
This is an example in which the band gap at the i / Si interface (Si / i interface) is equal to the band gap of the region 322. Figure 3-3, is provided with a p / i interface (i / p interface) near, and i / Si interface (Si / i interface) constant band gap regions 332 and 333 in the i-type layer in the vicinity.
Thus, when a reverse bias is marked addition to the photovoltaic element, in which more dark current decreases, the open circuit voltage of the photovoltaic element is increased.

FIGS. 3-4 to 3-7 show the vicinity of the i / Si interface (Si / i interface) or / and the p / i interface (i / i interface).
a constant band gap in the i-type layer near the (p interface), and an i / Si interface (Si / i interface) and / or p
5 is an example of the photovoltaic device of the present invention having a region where the band gap changes rapidly in the direction of the / i interface (i / p interface).

FIG. 3-4 shows regions 342 and 343 having constant band gaps in the i-type layer near the p / i interface (i / p interface) and near the i / Si interface (Si / i interface). There is a region 341 where the band gap changes, and the region 341 has a p / i interface (i
In this example, the band gap of the region 341 and the band gaps of the regions 342 and 343 are continuous. The electrons and holes photoexcited in the region where the band gap of the i-type layer is changed by continuing the band gap can be efficiently converted into the n-type layer (second n-type layer) and the second p-type layer (p (Mold layer). Further, particularly, the regions 342 and 34 having a constant band gap.
In the region where the band gap of the i-type layer is abruptly changed when 3 is as thin as 5 nm or less, the dark current when a reverse bias is applied to the photovoltaic element can be reduced. Can increase the open-circuit voltage.

FIG. 3-5 shows that the area 351 where the band gap changes is equal to the areas 352 and 35 where the band gap is constant.
This is an example in which the connection with No. 3 is discontinuously and relatively loosely connected.
However, since they are gently connected in the direction in which the band gap expands in the band gap changing region and the band gap changing region, carriers that are photoexcited in the band gap changing region can efficiently have the band gap constant. Implanted into the region. As a result, the collection efficiency of the photoexcited carriers increases. Whether the region with a constant band gap and the region with a changing band gap are connected continuously or discontinuously depends on the layer thickness between the region with a constant band gap and the region with a rapidly changing band gap. It depends on. When the region having a constant band gap is 5 nm or less and the layer thickness of the region where the band gap changes rapidly is 10 nm or less, the region having a constant band gap and the region where the band gap changes are continuously formed. The connection increases the photoelectric conversion efficiency of the photovoltaic element. On the other hand, the layer thickness in the region where the band gap is constant is thicker than 5 nm and the layer thickness in the region where the band gap changes rapidly is 10%. When the band gap is constant and the region where the band gap is changed is discontinuously connected, the conversion efficiency of the photovoltaic element is improved.

FIG. 3-6 shows an example in which a region where the band gap is constant and a region where the band gap changes are connected in two stages. In this example, the position where the band gap is extremely small is closer to the p / i interface (i / p interface) than the center position of the i-type layer. The region 3 where the bandgap is changing is obtained by connecting the bandgap to a fixed region 362 having a wide bandgap through a step of gradually expanding the bandgap from a position where the bandgap is extremely small and a step of rapidly expanding the bandgap.
The carrier photo-excited at 61 can be collected efficiently. In FIG. 3-6, the i / Si interface (Si
The i-type layer near the (/ i interface) has a region where the band gap changes rapidly toward the i / Si interface (Si / i interface).

FIG. 3-7 shows that the i-type layer near the i / Si interface (Si / i interface) and the p / i interface (i / p interface) has a region with a constant band gap, and Band gap constant region 372 near the i interface (i / p interface)
Is connected to the i / Si interface (Si / Si) through the band gap change in two steps from the band gap change region 371.
This is an example in which a region 373 having a constant band gap at the (i-interface) is connected by a sudden change in the band gap.

As described above, the internal strain can be reduced by connecting the constant band gap region and the band gap changing region in a state where the constituent elements are similar. As a result, even if annealing is performed for a long period of time under vibration, the phenomenon that a weak bond in the i-layer is cut and the defect level increases, and the photoelectric conversion efficiency decreases, is unlikely to occur.
High photoelectric conversion efficiency can be maintained.

In the present invention, the preferable range of the minimum value of the band gap of the i-type layer containing silicon atoms and carbon atoms is variously selected depending on the spectrum of the irradiation light, but is 1.7 to 2.0 eV. Is desirable. Further, in the photovoltaic device of the present invention in which the band gap is continuously changed, the inclination of the tail state of the valence band is an important factor that affects the characteristics of the photovoltaic device. It is preferable that the slope of the tail state at the minimum value is smoothly continuous from the slope of the tail state at the maximum band gap.

The photovoltaic element having the pin / pn (nip / np) structure has been described above.
n (nipnip / np) structure or pinpinpin /
The present invention can also be applied to a photovoltaic element in which a pin structure such as a pn (nipnipnip / np) structure is stacked. FIG. 4 is a schematic explanatory view of a manufacturing apparatus suitable for forming a deposited film of a photovoltaic element of the present invention. The manufacturing apparatus includes a deposition chamber 401, a vacuum gauge 402, an RF power supply 403, a substrate 404, a heater 405, a conductance valve 407, an auxiliary valve 408, a leak valve 409, an RF
Electrode 410, gas introduction tube 411, microwave waveguide 41
2. Dielectric window 413, shutter 415, source gas supply device 2000, mass flow controller 2011-2
017, valves 2001 to 2007, 2021 to 202
7, pressure regulators 2031 to 2037, raw material gas cylinder 2
041 to 2047 and the like.

The details of the deposition mechanism of the microwave plasma CVD method used for forming the photovoltaic device of the present invention are not known, but are considered as follows. Source gas 10
Microwave energy required for 0% decomposition (MP
abbreviated as "w") to decompose the source gas by applying lower microwave energy to the source gas;
It is considered that an active species suitable for forming a deposited film can be selected by making RF energy higher than MPw act on the source gas simultaneously with microwave energy. Furthermore, when the source gas is decomposed, the internal pressure in the deposition chamber is 50 mTorr.
In the following conditions, it is considered that the gas phase reaction is suppressed as much as possible because the mean free path of active species suitable for forming a high-quality deposited film is sufficiently long. And the internal pressure in the deposition chamber is 50
It is considered that the RF energy hardly affects the decomposition of the source gas in the state of mTorr or less and controls the potential between the plasma and the substrate in the deposition chamber. That is, in the case of the microwave plasma CVD method, the potential difference between the plasma and the substrate is small, but by introducing RF energy simultaneously with the microwave energy, the potential difference between the plasma and the substrate (the plasma side is + and the substrate side is-) is reduced. Can be bigger. Since the plasma potential is positive and high with respect to the substrate, active species decomposed by the microwave energy are deposited on the substrate, and at the same time, + ions accelerated by the plasma potential collide with the substrate and generate It is considered that the relaxation reaction is promoted and a high-quality deposited film is obtained. In particular, this effect becomes remarkable when the deposition rate is several nm / sec or more.

Further, since RF has a high frequency unlike DC, the difference between the plasma potential and the substrate potential is determined by the distribution of ionized ions and electrons. That is, the potential difference between the substrate and the plasma is determined by the synergistic effect between the ions and the electrons. Therefore, there is an effect that spark is less likely to occur in the deposition chamber. As a result, a stable glow discharge can be maintained for a long time of 10 hours or more.

In addition, when depositing a layer with a changed band gap, the flow rate and the flow rate ratio of the source gas change with time or spatially. It is necessary to change it appropriately. On the other hand, in the above-described method of forming a deposited film, the ratio of ions changes due to a temporal or spatial change in the flow rate and flow rate ratio of the source gas. The RF self-bias automatically changes accordingly. As a result, when RF is applied to the RF electrode to change the source gas flow rate and the source gas flow ratio, D
The discharge is very stable as compared with the case of the C bias.

In addition, in the deposited film forming method of the present invention, in order to change the band gap in the i-type layer,
It is effective to temporally change the flow ratio between the silicon atom-containing gas and the carbon-containing gas during layer formation,
It is preferable to mix the above gas at a distance of 5 m or less from the deposition chamber. If the source gases are mixed at a distance of more than 5 m, even if the mass flow controller is controlled in response to a desired change in band gap, the source gas mixing positions are far apart, so that the source gas changes late and the source gases may not be mixed. Diffusion occurs, causing a deviation from a desired band gap. That is, if the mixing positions of the source gases are too far apart, the controllability of the band gap is reduced.

Further, in order to change the hydrogen content contained in the i-type layer in the layer thickness direction, the RF energy applied to the RF electrode should be increased where the hydrogen content is desired to be increased.
Where the hydrogen content is to be reduced, the RF energy applied to the RF electrode may be reduced. Although the detailed mechanism is still unknown, R
It is considered that when the F energy is increased, the plasma potential increases, and the hydrogen ions are more accelerated toward the substrate, so that more hydrogen atoms are contained in the i-type layer.

Further, when DC energy is applied simultaneously with the RF energy, the DC voltage applied to the RF electrode may be increased by increasing the DC voltage applied to the RF electrode where the hydrogen atom content is desired to be increased. When it is desired to reduce the DC voltage, a DC voltage applied to the RF electrode may be applied with a small voltage having a positive polarity. Although the detailed mechanism is still unknown, increasing the DC energy applied to the RF electrode raises the plasma potential and causes more hydrogen ions in the i-type layer to be accelerated toward the substrate. It is considered that a hydrogen atom is contained.

Further, as another method of changing the hydrogen content contained in the i-type layer in the layer thickness direction, a gas containing a silicon atom and a halogen atom (X) (for example,
_{SiX 4, Si 2 X 6,} SiH N X 4-N, Si 2 H N X 6-N , etc.)
And a gas containing no halogen atoms but containing silicon atoms (eg, SiH ₄ , Si ₂ H ₆ , Si ₃ H ₈ , S
iD ₄ , Si ₂ HD ₅ , SiH ₂ D ₂ , SiH ₃ D, SiD ₃
H, Si ₂ D ₃ H _3, etc.) to form an i-type layer. It is at the point you want to reduce the hydrogen content and the proportion of gas containing both the sheet <br/> halogen atom for silicon atom-containing gas, and a silicon atom (Y),
Where the hydrogen content is to be reduced, the ratio (Y) may be reduced. Is a natural unknown Yi for detailed mechanisms, in the above gas deposition chamber containing a halogen atom, introducing more, increase the amount of radicals containing halogen atoms excited by microwave plasma It is considered that the halogen atom of the halogen atom-containing radical and the hydrogen atom present in the i-type layer cause a substitution reaction, and the hydrogen content in the i-type layer is reduced.

Further, as another method for changing the hydrogen content contained in the i-type layer in the thickness direction, a halogen lamp or a xenon lamp is provided in the deposition chamber.
These lamps are flashed during the formation of the mold layer to temporarily raise the substrate temperature. At that time, where the hydrogen content is to be reduced, the number of flashes per unit time is increased by increasing the number of flashes per unit time, and temporarily increasing the substrate temperature. The substrate temperature may be temporarily lowered. By temporarily increasing the substrate temperature,
It is considered that the elimination reaction of hydrogen from the surface of the i-type layer is activated.

The method of forming a deposited film used for manufacturing the photovoltaic element of the present invention is performed, for example, as follows.
First, a substrate 404 for forming a deposited film is placed in a deposition chamber 401 shown in FIG.
And the deposition chamber is sufficiently evacuated to 10 ^-4 Torr or less. For this exhaust, a turbo molecular pump or an oil diffusion pump is suitable. In the case of an oil diffusion pump, the internal pressure of the deposition chamber
When it becomes 0 ^-4 Torr or less, H ₂ , He, Ar, Ne,
It is preferable to introduce a gas such as Kr or Xe into the deposition chamber. After sufficiently exhausting the deposition chamber, H ₂ , He, Ar, N
Gases such as e, Kr, and Xe are introduced into the deposition chamber so that the pressure in the deposition chamber is substantially the same as when the source gas for forming the deposited film is flowed. The pressure in the deposition chamber is 0.5 to 50
mTorr is the optimal range. When the internal pressure in the deposition chamber becomes stable, the heater 405 is turned on and the substrate
Heat to 00-500 ° C. When the temperature of the substrate is stabilized at a predetermined temperature, gases such as H ₂ , He, Ar, Ne, Kr, and Xe are stopped, and a predetermined amount of a raw material gas for forming a deposited film is introduced from a gas cylinder into a deposition chamber via a mass flow controller. I do.

The supply amount of the source gas for forming the deposited film introduced into the deposition chamber is determined appropriately according to the volume of the deposition chamber. On the other hand, the internal pressure in the deposition chamber when the source gas for deposition film formation is introduced into the deposition chamber is a very important factor in the deposition film formation method, and the optimal internal pressure in the deposition chamber is:
In the case of microwave plasma CVD, 0.5 to 50 mT
orr is preferred.

[0061] Also, has it the deposited film forming method, microwave energy introduced into the deposition chamber for deposition film formation,
It is an important factor. The microwave energy is appropriately determined depending on the flow rate of the source gas introduced into the deposition chamber, but is smaller than the microwave energy (MPw) required to decompose the source gas by 100%. The preferred range is 0 . 005-1W
/ Cm ³ . A preferable frequency range of the microwave energy is 0.5 to 10 GHz. In particular <br/>, it is suitable frequencies near 2.45 GHz. Also ,
To form the deposited film with a reproducible by the deposition film forming method, and for forming a deposited film for several tens of hours for several hours, Ri stability is very important in the frequency of the microwave energy, the frequency Is preferably in the range of ± 2% or less. Furthermore, it is ripple preferably ± 2% or less microwave range.

Further, in the method of forming a deposited film, the RF energy introduced simultaneously with the microwave energy into the deposition chamber is a very important factor in combination with the microwave energy, and the preferable range of the RF energy is Is 0.01 to 2 W / cm ³ . RF
A preferable frequency range of the energy is 1 to 100.
MHz. In particular, 13.56 MHz is optimal. Further, the variation of the RF frequency is preferably within ± 2%, and the waveform is preferably a smooth waveform. When the RF energy is supplied, the area is appropriately selected depending on the area ratio between the area of the RF electrode for supplying RF energy and the area of the ground. When the width is narrow, it is better to ground the self-bias (DC component) on the power supply side for supplying RF energy. If the self-bias (DC component) on the power supply side for supplying RF energy is not grounded,
It is preferable that the area of the RF electrode for supplying RF energy be larger than the area of the ground to which the plasma contacts.

As described above, microwave energy is introduced from the waveguide 412 into the deposition chamber via the dielectric window 413, and at the same time, RF energy is supplied from the RF power source 403 to the RF electrode 41.
0 to the deposition chamber. In such a state, the source gas is decomposed for a desired time to form a deposited film having a desired thickness on the substrate. Thereafter, the introduction of microwave energy and RF energy was stopped, the deposition chamber was evacuated, and H ₂ , H
After sufficiently purging with a gas such as e, Ar, Ne, Kr, or Xe, the deposited non-single-crystal semiconductor film is taken out of the deposition chamber.

Further, in addition to the RF energy, the R
A DC voltage may be applied to the F electrode 410. As the polarity of the DC voltage, it is preferable to apply the voltage so that the RF electrode becomes positive. The preferable range of the DC voltage is about 10 to 300V. In the above-described method for forming a deposited film, the following compounds are suitable as the compounds listed as the source gas for silicon deposition.

Specific examples of the gasizable compounds containing silicon atoms include SiH ₄ , Si ₂ H ₆ and _Six
4 (X: halogen _{atom), SiX H 3, SiX 2} H 2, Si
X ₃ H, Si ₂ X ₆ , Si ₃ H ₈ , SiD ₄ , SiHD ₃ , S
iH ₂ D ₂ , Si H ₃ D, Si F ₂ D ₂ , Six ₂ D ₂ , Si
D ₃ H, Si ₂ D ₃ H _{3 and the} like (collectively abbreviated as “compound (Si)”).

The gasizable compounds containing carbon atoms include CH ₄ , CD ₄ , C ₂ H _{2n + 2} (n is an integer), C 4
_n H _2n (n is an integer), C _n X _{2n + 2} (n is an integer, X: halogen atom), C _n X _2n (n is an integer), C ₂ H ₂ , C ₆
H ₅ , CO ₂ , CO and the like (collectively abbreviated as “compound (C)”). In the present invention, the valence electron controlling agent introduced into the non-single-crystal semiconductor layer for controlling the valence electrons of the non-single-crystal semiconductor layer includes Group III atoms, Group V atoms and Group VI atoms of the periodic table. No.

In the present invention, as a starting material for introducing a group III atom (generally abbreviated as “compound (III)”), the one effectively used is specifically for introducing a boron atom. Are B ₂ H ₆ , B ₄ H ₁₀ , B ₅ H ₉ ,
_{B 5 H 11, B 6 H} 10, B 6 H 1 2, B 6 H 14 , etc. borohydride, BF _3, BCl _3, can be exemplified BBr _3, etc. boron halides like. In addition, AlCl ₃ , Al
(CH ₃ ) ₃ , GaCl ₃ , InCl ₃ , TlCl _{3 and the} like can also be mentioned.

In the present invention, a starting material for introducing a group V atom is used.
Goods (collectively abbreviated as “compound (V)”)
It is used specifically for introducing phosphorus atoms.
PH _Three, P_TwoH_FourPhosphorus hydride, PH_FourI, PF_Three, P
F_Five, PCl_Three, PCl_Five, PBr_Three, PBr_Five, Pl
_ThreeHalogenated phosphorus, P_TwoO_Five, POCl_ThreeEtc. oxygenation
Compounds. In addition, AsH_Three, AsF_Three, As
Cl_Three, AsBr_Three, AsF_Five, SbH_Three, SbF_Three,
SbF_Five, SbCl_Three, SbCl_Five, BiCl _Five, Bi
Br_ThreeAnd the like.

[0069] In have you to the present invention, being effectively used as starting materials for the group VI atoms introduced (collectively referred to as "Compound (VI)") _{is, H 2 S, SF 4,} SF 5 , S
O ₂ , SO ₂ F ₂ , COS, CS ₂ , H ₂ Se, SeF ₆ , T
eH ₂ , TeF ₆ , (CH ₅ ) ₂ Te, (C ₂ H ₃ ) ₂ Te and the like. Group III atoms of the periodic table, which is introduced into the formed i-type layer of non-single-crystal semiconductor material, Group V atoms,
The preferable introduction amount of Group VI atom is 1000 ppm or less. In order to achieve the object of the present invention, the group III atoms and group V atoms of the periodic table in the i-type layer or the group III atoms and Group VI atoms, or the group III atoms and the V, It is preferred that the Group A and Group VI atoms be added so as to compensate for both.

The compound capable of being gasified is H ₂ ,
It may be appropriately diluted with a gas such as D ₂ , He, Ne, Ar, Xe, or Kr and introduced into the deposition chamber. In particular, the most suitable gas for diluting the gasifiable compound is H ₂ , D ₂ ,
He and Ar are mentioned. Examples of the nitrogen-containing gas introduced to make the i-type layer of the non-single-crystal semiconductor layer contain nitrogen include N ₂ , NH ₃ , ND ₃ , NO, NO ₂ , and N ₂ O (collectively, “compound (N)”). Abbreviated as ").

Oxygen is contained in the i-type layer of the non-single-crystal semiconductor layer.
The oxygen-containing gas introduced for_Two, C
O, CO_Two, NO, NO_Two, N_TwoO, CH_ThreeCH_TwoO
H, CH _ThreeOH, etc. (collectively abbreviated as "compound (O)")
). In the photovoltaic device of the present invention,
Out of the second p-type layer, the n-type layer, the first p-type layer, or the second
At least one of the n-type layer, the p-type layer, and the first n-type layer
It is preferable to have a laminated structure. The photovoltaic device of the present invention
In the laminated structure, the main constituent elements are silicon, carbon, and acid
At least one element selected from nitrogen and nitrogen
As a valence electron controlling material
Or a layer containing a group V element or a group VI element (A
Layer) and a Group III element or Group V element of the periodic table or
Is composed of a layer (B layer) containing a Group VI element as a main constituent element
Is done.

By using the laminated structure of the present invention for the doping layer, the donor concentration or the acceptor concentration of the doping layer can be improved as compared with the conventional one, and the open-circuit voltage of the photovoltaic element can be increased. Furthermore, the A layer is a material that is not doped at a high concentration (light doping),
And by using a material with a small light absorption coefficient,
Since more light can enter the i-type layer or the pn junction, the short-circuit photocurrent of the photovoltaic element can be improved.

Further, the photovoltaic device having the laminated structure of the present invention can considerably suppress the decrease in photoelectric conversion efficiency even for long-time annealing such as vibration. The detailed mechanism is still unknown, but is considered as follows. In the conventional laminated structure, since the constituent elements are rapidly changing, considerable strain and stress are generated. However, since the layer A of the present invention contains carbon or / and / or oxygen and / or nitrogen, the generated strain and stress are alleviated inside the layer A, and therefore, even for long-time annealing such as vibration. It is considered that a decrease in photoelectric conversion efficiency can be suppressed.

Further, the photovoltaic device having a laminated structure of the present invention can considerably suppress a decrease in photoelectric conversion efficiency even when irradiated with light for a long time. The detailed mechanism is still unknown, but is considered as follows. When light is irradiated for a long time, a dangling bond is generated inside the A layer. It is considered that light degradation can be suppressed.

The A layer is made of an amorphous material (denoted as a-), a microcrystalline material (denoted as μc-), a polycrystalline material (denoted as poly-), or a single crystal material (denoted as c-). Consists of As the amorphous material, for example, a-Si: H, a-Si: HX, a-SiC: H,
a-SiC: HX, a-SiO: H, a-SiO: H
X, a-SiN: H, a-SiN: HX, a-SiO
N: H, a-SiON: HX, a-SiOCN: H, a
—SiOCN: HX, (X: halogen atom) and the like.

As a microcrystalline material, for example, μc-S
i: H, μc-SiC: H, μc-Si: HX, μc-
SiC: HX, μc-SiO: H, μc-SiN: H,
μc-SiON: HX, μc-SiOCN: HX, and the like. As a polycrystalline material, for example, poly-S
i: H, poly-Si: HX, poly-SiC:
H, poly-SiC: HX, poly-Si, pol
y-SiC, and the like.

As a single crystal material, for example, c-Si,
c-SiC and the like. n (p) -type layer, second p
When the (n) type layer has a laminated structure, a microcrystalline material, a polycrystalline material, or a single crystal material having a small absorption coefficient of short-wavelength light is preferably used as the A layer. In order to form the p-type A layer, a p-type valence electron controlling agent (the periodic table II)
Group I atoms B, Al, Ga, In, Tl) are added and n
In order to form the type A layer, an n-type valence electron controlling agent (group V atom P, As, Sb, Bi or / and periodic table group VI atom S, Se, Te) is added. Let it.

The amount of Group III element in the periodic table added to the p-type A layer, or the group V atom in the periodic table to the n-type A layer;
The optimum amount of the Group VI atom to be added is 10 to 10000 ppm. When the A-type layer is composed of a microcrystalline material or a polycrystalline material, hydrogen atoms (H, D) or halogen atoms contained in the A layer work to compensate for dangling bonds of the A layer. , To improve the doping efficiency. The optimum amount of hydrogen atoms or halogen atoms added to the A layer is 0 to 10 at%. In the vicinity of the interface of the layer A, a preferred distribution form is one in which a large content of hydrogen atoms and / or halogen atoms is distributed. A preferred range is 1.1 to 2.5 times the content. Thus ,
Reducing the defect level or layer within the stress of the interface near by increasing the content of hydrogen atoms or halogen atoms near the interface, yet is able to relieve the mechanical strain, the photovoltaic element of the present invention Can increase the photovoltaic power and the photocurrent. Accordingly, the layer thickness of the A layer is preferably 5 to 30 Å.

The method for forming the layer A is plasma CVD.
And a photo-CVD method, and a plasma CVD method is particularly preferably used. When forming the A layer by these methods,
The following compounds that can be gasified and a mixed gas of the compounds can be given. Specific examples of the gasizable compound containing a silicon atom include the aforementioned compound (S
i).

The compound (C) described above is specifically mentioned as a gasizable compound containing a carbon atom.
Examples of the nitrogen-containing gas include the compound (N) described above. Examples of the oxygen-containing gas include the compound (Ο) described above. Examples of the substance introduced into the p-type A layer include Group III atoms of the periodic table, and examples of the atom introduced into the n-type A layer include Group V atoms and Group VI atoms.

The compounds that can be effectively used as starting materials for introducing Group III atoms include the compounds (II) described above.
I) can be mentioned. In particular, B ₂ H ₆ and BF ₃ are suitable. These compounds are usually diluted to a desired concentration with a gas such as H ₂ , He, or Ar and stored in a high-pressure cylinder. V
Effectively used as a starting material for introducing a group atom is
The compound (V) described above can be mentioned.
H ₃ and PF ₃ are suitable, and these compounds are usually
It is diluted to a desired concentration with a gas such as H ₂ , He, or Ar and stored in a high-pressure cylinder.

Compounds (VI) described above are effectively used as starting materials for introducing Group VI atoms, and H ₂ S is particularly suitable.
It is diluted to a desired concentration with a gas such as H ₂ , He, or Ar and stored in a high-pressure cylinder. When the A layer is formed by a plasma CVD method, an RF plasma CVD method and a microwave plasma CVD method are preferable. When depositing by RF plasma CVD, a capacitively coupled RF plasma CVD is suitable.

When depositing by the RF plasma CVD method,
Substrate temperature in deposition chamberIs100-600 ° C, internal pressureIs0.1
-10 Torr, RF powerIs0.01-1W / c
m^Two, Deposition rateIs0.1-1Å/ Sec is the optimal condition
It is mentioned. Also,The gasifiable compound,
H_Two, D_Two, He, Ne, Ar, Xe, Kr, etc.
It may be diluted and introduced into the deposition chamber.

[0084] Especially microcrystalline, or polycrystalline, or when depositing layer A ing from a single crystal material with hydrogen gas 2-10
It is preferable to dilute the source gas by a factor of 0 and to introduce a relatively high RF power. An RF frequency of 1 MHz to 100 MHz is a suitable range, and a frequency near 13.56 MHz is particularly optimal. In the case of depositing by a microwave plasma CVD method, a microwave plasma CVD apparatus is suitable for a method in which a microwave is introduced into a deposition chamber through a waveguide through a dielectric window (alumina ceramics, quartz, boron nitride, etc.) 413. I have. Although the above-described deposition film formation method suitable for forming the i-type layer is also a suitable deposition method, a deposition film applicable to a photovoltaic element can be formed under a wider range of deposition conditions. That is, the substrate temperature in the deposition chamber is 100 to 600 ° C., the internal pressure is 0.5 to 30 mTorr,
Microwave power is preferably 0.005 to 1 W / cm ³ , and microwave frequency is preferably 0.5 to 10 GHz.

The compound capable of being gasified is H ₂ , D ₂ ,
The gas may be appropriately diluted with a gas such as He, Ne, Ar, Xe, or Kr and introduced into the deposition chamber. Especially microcrystalline or polycrystalline,
Alternatively, when depositing the A layer made of a single crystal material, it is preferable to dilute the source gas by 2 to 100 times with hydrogen gas and to introduce relatively high microwave power.

When the layer A is deposited by the photo-CVD method, a low-pressure mercury lamp is used as a light source and the substrate temperature is 100 to 60.
0 ° C., internal pressure 0.1 to 10 Torr, deposition rate 0.0
Cited as optimum condition 1 to 1 Å / se c is, 1～100P mercury with introducing a compound capable of the gasification
pm may be introduced. Examples of the compound _{(Si), Si 2 H 6} , Si 2 H N X 6-N: higher silane of (X a halogen atom) and the like are preferably used.

The compound capable of being gasified is H ₂ , D ₂ ,
The gas may be appropriately diluted with a gas such as He, Ne, Ar, Xe, or Kr and introduced into the deposition chamber. Especially microcrystalline or polycrystalline,
Alternatively, when depositing the A layer made of a single crystal material, it is preferable to introduce the source gas after diluting the source gas by 2 to 100 times with hydrogen gas.

When the main constituent atom of the B layer is laminated with the p-type A layer, the main group atom is a group III atom of the periodic table (eg, B, Al,
Ga, In, Tl ) , and when laminated with an n-type A layer, a group V atom of the periodic table (for example, P, As, Sb, B)
i) or / and Group VI atoms of the Periodic Table (eg S,
Se, Te). The thickness of the B layer is preferably 5 to 30 Å.

As a method for forming the layer B, plasma CVD is used.
Method, a photo-CVD method or the like is preferably used. When the B layer is formed by these methods, the following compounds that can be gasified and a mixed gas of the compounds can be exemplified. II
The compound (III) described above can be effectively used as a starting material for introducing a group I atom, and B ₂ H ₆ and B (CH ₃ ) ₃ are particularly suitable.

The compound (V) described above can be effectively used as a starting material for introducing a group V atom. The compound (VI) described above is effectively used as a starting material for introducing a Group VI atom.
When the B layer is formed by a plasma CVD method, an RF plasma CVD method and a microwave plasma CVD method are preferable. When depositing by RF plasma CVD, a capacitively coupled RF plasma CVD is suitable.

When depositing by the RF plasma CVD method,
The substrate temperature in the deposition chamber is 100 to 600 ° C, and the internal pressure is 0.1
~10 T оrr, RF power - is 0.1~2W / cm ^2,
The deposition rate can be mentioned as an optimum condition is 0.1 to 2 Å / sec. Further , the compounds capable of being gasified are H ₂ , D ₂ , H
It may be appropriately diluted with a gas such as e, Ne, Ar, Xe, or Kr and introduced into the deposition chamber.

[0092] When deposited by microwave plasma CVD, microwave plasma CVD apparatus, a deposition chamber in a dielectric window (alumina Ceramic box, quartz, nitride boric iodine, etc.) 413
A method of introducing microwaves through a waveguide via a waveguide is suitable. Although a deposition film forming method most suitable for i- type layer formation is also a suitable deposition method, a deposition film applicable to a photovoltaic element can be formed under a wider range of deposition conditions. That is, the substrate temperature in the deposition chamber is 100 to 600 ° C., and the internal pressure is 0.5 to 30 mT.
оrr, microwave power is 0.01-1 W / cm ³ ,
The preferred range of the microwave frequency is 0.5 to 10 GHz.

[0093] Also, a compound capable of the gasification, H _2,
It may be appropriately diluted with a gas such as D ₂ , He, Ne, Ar, Xe, or Kr and introduced into the deposition chamber. When depositing layer B in the optical CVD method, using a low-pressure mercury lamp as a light source, a substrate temperature of 100 to 600 ° C., the internal pressure is 0.1~10 T оr
r, the deposition rate is given as optimum condition is 0.01~2 Å / se c, mercury is introduced a compound capable of the gasification may be introduced about 1 to 100 ppm.

[0094] Also, a compound capable of the gasification, H _2,
It may be appropriately diluted with a gas such as D ₂ , He, Ne, Ar, Xe, or Kr and introduced into the deposition chamber. It layered form a laminated structure for use in the photovoltaic device of the present invention, rather than to desirable ending in A layer starting from the layer A, for example, ABA, ABAB
A, ABABABA etc., (AB) laminated form of _n A, there <br/> physician _{A 1 B 1 A 2, A} 1 B 1 A 2 B 2 A 3 , _{etc., (A n B n) A} n + 1
Lamination form. However, when using the laminated structure on the second p-type layer may end in B layer starting from the layer A, for example, AB, ABAB, ABABAB or the like,
(AB) _n laminated form, or A ₁ B ₁ , A ₁ B ₁ A ₂ B ₂
And (A _n B _n ).

Next, the components of the photovoltaic device of the present invention will be described in detail. The substrate (102, 122) may be a polycrystalline silicon substrate or a monocrystalline silicon substrate, and further a polycrystalline silicon layer or a monocrystalline silicon A stack of layers may be used.

When using polycrystalline silicon as the substrate,
100 to 5 ingots made by casting method (Latest solar power technology, edited by Yoshihiro Hamakawa, Maki Shoten)
It is sliced to a thickness of about 00 μm and used, or a ribbon-shaped silicon polycrystal made by passing a carbon fiber net through a silicon melt, or polycrystalline silicon is directly obtained from the silicon melt. You may use what cooled slowly while pulling out. In each case,
In order to reduce many trap levels existing in the grain boundary, annealing at a substrate temperature of 500 to 900 ° C. in a hydrogen atmosphere or a substrate temperature of 3 ° C.
It is desirable to perform hydrogen plasma treatment at 00 to 900 ° C. or to irradiate the substrate with a laser beam for annealing.

When using single crystal silicon as the substrate,
Use an ingot produced by the CZ (Chocolarski) method by slicing it to a thickness of about 100 to 500 μm, or use a ribbon-like silicon single crystal produced by passing a carbon fiber net through a silicon melt. Alternatively, a material that is slowly cooled while pulling single crystal silicon directly from a silicon melt may be used.

The conductive support used for laminating a polycrystalline silicon layer or a single crystal silicon layer on the support may be, for example, NiCr, stainless steel, Al, Cr,
Mo, Au, Nb, Ta, V, Ti, Pt, Pb, Sn
And alloys thereof. Similarly, as the electrically insulating support, polyester, polyethylene, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride,
Films of synthetic resins such as polystyrene, polyamide, etc.
Alternatively, a sheet, glass, ceramics, paper, or the like may be used. Preferably, at least one surface of these insulating supports is subjected to conductive treatment, and a polycrystalline silicon layer or a single-crystal silicon layer is provided on the conductive-treated surface side.

For example, in the case of glass, N
iCr, Al, Cr, Mo, Ir, Nb, Ta, V, T
i, Pt, Pb, In ₂ O ₃ , ITO (In ₂ O ₃ + S
nO ₂ ) or the like to provide conductivity by providing a thin film or NiCr, Al, Ag, Pb, Zn, N
i, Au, Cr, Mo, Ir, Nb, Ta, V, Tl,
A thin metal film such as Pt is provided on the surface by vacuum evaporation, electron beam evaporation, sputtering, or the like, or the surface is laminated with the metal to impart conductivity to the surface. The shape of the support may be a sheet having a smooth surface or an uneven surface. The thickness is determined as appropriate so that a desired photovoltaic element can be formed. It can be as thin as possible. However, the thickness is usually 10 μm or more from the viewpoints of production and handling of the support, mechanical strength and the like.

In order to form a polycrystalline silicon layer on the surface of the support, a non-single-crystal silicon layer is formed on the support by using a plasma CVD method, a thermal CVD method, a photo CVD method or the like. After that, there is a method of recrystallization by melting with a heater, a laser, an electron beam, or the like. (SOI structure formation technology, edited by Shizujiro Furukawa, industrial book) Also, fine holes or projections are provided on a support, and these are used as growth nuclei, and plasma CVD, thermal CVD, light C
There is also a method of growing a polycrystalline silicon layer in the lateral direction by the VD method. Further, these methods may be used in combination.

In order to increase the collection efficiency of the incident light, it is desirable to make the surface of the substrate into pyramid-like irregularities (texture). To perform texture processing, 1
It may be immersed in a 10%, 60% hydrazine aqueous solution for about 10 minutes, or may be immersed in a 100%, 1% NaOH aqueous solution for about 5 minutes. First p (n) -type layer (103, 123) The first p (n) -type layer is an important layer that affects the characteristics of the photovoltaic element. The details of the case where the first p (n) -type layer has a laminated structure are as described above, but the case where the first p (n) -type layer is formed of a single layer will be described below.

The first p (n) -type layer is made of a microcrystalline material (μc
-), Or a polycrystalline material (poly-), or a single crystal material (c-). As microcrystalline materials, for example, μc-Si: H, μc-SiC: H, μc-S
i: HX, μc-SiC: HX, μc-SiGe: H,
μc-SiO: H, μc-SiGeC: H, μc-Si
N: H, μc-SiON: HX, μc-SiOCN: H
X, etc. (X: halogen atom).

As the polycrystalline material, for example, poly-S
i: H, poly-Si: HX, poly-SiC:
H, poly-SiC: HX, poly-SiGe:
H, poly-Si, poly-SiC, poly-S
iGe and the like. As the crystal material, for example, c-
Si, c-SiC, c-SiGe and the like can be mentioned.

[0104] conductivity type to the p-type p-type valence electron control agent (the periodic table Group III atom B, Al, Ga, In,
Tl) is added in high concentration. Conductivity type to the n-type, n-type valence electron controlling agent (the periodic table Group V atom P, A
s, Sb, Bi and / or the periodic table group VI atoms
S, Se, Te) are added at a high concentration. The addition amount of the periodic table Group III atom to the first p-type layer, or the group V of the periodic table of the first n-type layer, the addition amount of the Group VI atoms is 0.1～10At% It is listed as the optimal amount.

Further, the first p (n) type layer is made of a microcrystalline material,
Alternatively, when it is made of a polycrystalline material, the first p
Hydrogen atoms (H, D) or halogen atoms contained in the (n) -type layer work to compensate for dangling bonds of the p-type layer or the n-type layer, and improve doping efficiency. First
The optimal amount of hydrogen atoms or halogen atoms added to the p (n) -type layer is 0 to 10 at%. A preferred distribution form is one in which a large content of hydrogen atoms and / or halogen atoms is distributed near the p / substrate interface (n / substrate interface) and near the n / p interface (p / n interface). The preferred range of the content of hydrogen atoms and / or halogen atoms in the vicinity of the interface is 1.3 to 2.5 times the content in the bulk. As described above, by increasing the content of hydrogen atoms or halogen atoms near the p / substrate interface (n / substrate interface) and near the n / p interface (p / n interface), the defect level near the interface and the level in the layer are reduced. The stress can be reduced, and the mechanical strain can be reduced, and the photovoltaic power and the photocurrent of the photovoltaic device of the present invention can be increased.

The electric characteristics of the first p (n) -type layer of the photovoltaic element are preferably those having an activation energy of 0.2 eV or less, and those having an activation energy of 0.1 eV or less are optimal. Also <br/>, less preferably 100Ωcm as specific resistance, 1 [Omega
cm or less is optimal. Further, the thickness of the p-type layer and the n-type layer is 50 to 2000 Å is preferable. As a method for forming the first p (n) type layer, and a method of depositing a thin layer on a substrate, there is a method of mixing impurities into the interior from the surface of the substrate.

Examples of a method for forming a thin film layer on a substrate include a plasma CVD method, a thermal CVD method, and a photo CVD method.
As a method for mixing impurities into the substrate, a gas diffusion method, a solid phase diffusion method, an ion implantation method, or the like is used, and particularly, a gas diffusion method or a plasma CVD method is suitably used. When the first p (n) -type layer is formed by a plasma CVD method, as a source gas, a gasizable compound containing a silicon atom, a gasizable compound containing a carbon atom, and the like, and a mixed gas of the compound are used. And the like.

Specific examples of the gasizable compound containing a silicon atom include the compound (Si) described above. Specific examples of the gasizable compound containing a carbon atom include the compound (C) described above. Examples of the gasizable compound containing a germanium atom include G
_{eH 4, Ge 2 H 6,} GeH N X 4-N (X: halogen) compounds such as (collectively referred to as "compound (Ge)") can be mentioned.

Examples of the nitrogen-containing gas include the compound (N) described above. Examples of the oxygen-containing gas include the compound (O) described above. The compound (III) described above can be effectively used as a starting material for introducing a group III atom, and in particular, B ₂ H ₆ ,
BF ₃ is suitable and these compounds are usually H ₂ , H ₂
It is preferable to use it after diluting it to a desired concentration with a gas such as e or Ar.

The compound (V) described above can be used effectively as a starting material for introducing a group V atom. In particular, PH ₃ and PF ₅ are suitable. It is used after being diluted to a desired concentration with a gas such as H ₂ , He, or Ar. The compound (VI) described above is effectively used as a starting material for introducing a Group VI atom. H ₂ S is particularly suitable, and these compounds are usually H ₂ , He, Ar, etc. Diluted with the desired gas before use.

When the first p (n) -type layer is formed by a plasma CVD method, an RF plasma CVD method and a microwave plasma CVD method are preferable. When depositing by RF plasma CVD, a capacitively coupled RF plasma CVD is suitable. When depositing by the RF plasma CVD method,
The substrate temperature in the deposition chamber is 100 to 600 ° C, and the internal pressure is 0.1
-10 Torr, RF power is 0.01-5.0 W / c
The optimum conditions for m ³ and the deposition rate are 0.1 to 30 ° / sec.

The compounds capable of being gasified are H ₂ , H
It may be appropriately diluted with a gas such as e, Ne, Ar, Xe, or Kr and introduced into the deposition chamber. Especially μc-Si: H, μc-S
iC: H, μc-Si: HX, μc-SiC: HX, μ
c-SiO: H, μc-SiN: H, μc-SiON:
HX, μc-SiOCN: HX, poly-Si: H,
poly-Si: HX, poly-SiC: H, pol
y-SiC: HX, poly-Si, poly-SiC
In the case of depositing a layer having little light absorption at a short wavelength such as the above, it is preferable to dilute the source gas by 2 to 100 times with hydrogen gas and to introduce a relatively high RF power. The RF frequency is preferably in the range of I MHz to 100 MHz, and a frequency near 13.56 MHz is particularly optimal.

When depositing by the microwave plasma CVD method, the microwave plasma CVD apparatus uses a dielectric window (alumina ceramics, quartz, boron nitride, etc.) 413 in the deposition chamber.
A method of introducing microwaves through a waveguide via a waveguide is suitable. Although the above-described method for forming a deposited film that is optimal for forming the i-type layer is also a suitable deposition method, a deposited film applicable to a photovoltaic element can be formed under wider deposition conditions. That is,
The substrate temperature in the deposition chamber is 100 to 600 ° C, and the internal pressure is 0.5
~ 30mTorr, microwave power 0.005 ~ 1
W / cm ³ , microwave frequency is 0.5 to 10 GHz
Is a preferred range.

The compounds capable of being gasified are H ₂ , H
It may be appropriately diluted with a gas such as e, Ne, Ar, Xe, or Kr and introduced into the deposition chamber. Especially μc-Si: H, μc-S
iC: H, μc-Si: HX, μc-SiC: HX, μ
c-SiO: H, μc-SiN: H, μc-SiON:
HX, μc-SiOCN: HX, poly-Si: H,
poly-Si: HX, poly-SiC: H, pol
y-SiC: HX, poly-Si, poly-SiC
In the case of depositing a layer having a small light absorption at a short wavelength such as, for example, it is preferable to dilute the source gas by 2 to 100 times with hydrogen gas and to introduce a relatively high microwave power.

[0115] When forming the first p-type layer in the gas diffusion method, and the temperature of the n-type substrate to 800 to 950 ° C., introducing a diffusion gas into the deposition chamber, the periodic table Group III atom It is diffused near the substrate surface. The diffusion gas, include compounds described above (III) are particularly BCl _3, BB
r ₃ is suitable. These compounds may be introduced after being diluted to a desired concentration with a gas such as H ₂ , He, or Ar.

[0116] When forming the first n-type layer in the gas diffusion method, and the temperature of the p-type substrate to 800 to 950 ° C., introducing a diffusion gas into the deposition chamber, the periodic table Group V atom, Alternatively, Group VI atoms are diffused near the substrate surface. The diffusion gas, compound described above (V), or the compound (VI) can be mentioned, particularly suitable are POCl _3, P ₂ O _5. These compounds may be introduced after being diluted to a desired concentration with a gas such as H ₂ , He, or Ar.

[0117] When forming the first p-type layer by ion implantation, the periodic table Group III atom accelerated under high electric field, by irradiating the n-type substrate surface, inside the substrate a Group III atom Inject into For example, when boron is implanted, 1-1
0 × 10 ¹⁵ (pieces / cm ² ) of ¹¹ B ⁺ is preferably applied at an acceleration voltage of about 5 to 50 keV. When forming the first n-type layer by ion implantation, periodic table group V atoms or the V,
Group I atoms are accelerated under a high electric field, and the surface of the n-type substrate is irradiated to implant Group V atoms or Group VI atoms into the substrate. For example, when phosphorus is injected, 0.5 to 1
0 × 10 ¹⁵ (pieces / cm ² ) of ³¹ P ⁺ is preferably performed at an acceleration voltage of about ¹ to 10 keV.

The n (p) -type layers (104, 124) and the second
P (n) -type layer (107, 127) The n (p) -type layer and the second p (n) -type layer are important layers that affect the characteristics of the photovoltaic element. The details of the case where the n (p) -type layer and the second p (n) -type layer have a laminated structure are as described above. Is described below.

An n (p) type layer made of a non-single-crystal material,
Examples of the p (n) type layer include an amorphous material, a microcrystalline material, and a polycrystalline material. Examples of the amorphous material include a-Si: H, a-Si: HX, a-SiC: H, and a-Si: HX.
SiC: HX, a-SiGe: H, a-SiGeC: H
X, a-SiO: H, a-SiN: H, a-SiON:
HX, a-SiOCN: HX and the like.

As microcrystalline materials, μc-Si: H, μc
-SiC: H, μc-Si: HX, μc-SiC: H
X, μc-SiGe: H, μc-SiO: H, μc-S
iGeC: H, μc-SiN: H, μc-SiON: H
X, μc-SiOCN: HX and the like. As the polycrystalline material, for example, poly-Si: H, poly-S
i: HX, poly-SiC: H, poly-SiC:
HX, poly-SiGe: H, poly-Si, po
ly-SiC, poly-SiGe, and the like.

[0121] conductivity type to the p-type, p-type valence electron control agent (the periodic table Group III atom B, Al, Ga, In,
Tl) is added in high concentration in the above material. Conductivity type to the n-type, n-type valence electron controlling agent (the periodic table Group V atom P, As, Sb, Bi, periodic table group VI atom S, S
e, Te) are added in high concentration to the above materials.

In particular, the second p (n) -type layer is made of a microcrystalline material having little light absorption or a non-single crystalline material having a wide band gap, for example, μc-Si: H, μc-Si
C: H, μc-Si: HX, μc-SiC: HX, μc
-SiO: H, μc-SiN: H, μc-SiON: H
X, μc-SiOCN: HX, poly-Si: H, p
poly-Si: HX, poly-SiC: H, poly
-SiC: HX, poly-Si, poly-SiC,
a-SiC: H, a-SiC: HX, a-SiO: H,
a-SiN: H, a-SiON: HX, a-SiOC
N: HX or the like is suitable.

[0123] p-type layer, and the Periodic Table I of the second p-type layer
Amount 及 beauty n-type layer of Group II atoms and the periodic table added amount of Group V atoms and Group VI to the second n-type layer is 0.1 to 5
0 at% is mentioned as the optimum amount. Further , hydrogen atoms (H, H, and H) contained in the n (p) -type layer and the second p (n) -type layer
D) or a halogen atom serves to compensate for dangling bonds and to improve doping efficiency.
at% is mentioned as the optimum amount. In particular , when the n (p) -type layer and the second p (n) -type layer are made of a microcrystalline material or a polycrystalline material, hydrogen atoms or halogen atoms are 0.1 to 10
at% is mentioned as the optimum amount. Further , a preferred distribution form includes a large distribution of the content of hydrogen atoms and / or halogen atoms in the vicinity of each interface. A preferred range is 1.1 to 2 times the content. Thus, the defect level of the interface vicinity, the film stress is reduced by increasing the content of hydrogen atoms or halogen atoms in each vicinity of the interface, it is possible to relieve the mechanical strain, the light of the present invention The photovoltaic power and the photocurrent of the electromotive element can be increased.

The electrical characteristics of the n (p) -type layer and the second p (n) -type layer are preferably those having an activation energy of 0.2 eV or less, and most preferably those having an activation energy of 0.1 eV or less. Also <br/>, less preferably 100Ωcm as specific resistance, 1 [Omega
cm or less is optimal. Further, n layer thickness of (p) type layer is preferably from 10 to 1000 Å, 30 to 300 Å is optimal, the layer thickness of the second p (n) type layer is preferably from 10 to 500 Å,. 30 to 200 mm is optimal.

As a method for forming the n (p) -type layer and the second p (n) -type layer, a plasma CVD method, a thermal CVD method, a light CV
The D method is used, and particularly, the plasma CVD method is suitably used. N (p) -type layer, second p by plasma CVD
In the case of forming the (n) type layer, examples of the source gas include a gasizable compound containing a silicon atom, a gasizable compound containing a carbon atom, and a mixed gas of the compound.

Specific examples of the gasizable compound containing a silicon atom include the compound (Si) described above. Specific examples of the gasizable compound containing a carbon atom include the compound (C) described above. Examples of the gasizable compound containing a germanium atom include the compound (Ge) described above.

Examples of the nitrogen-containing gas include the compound (N) described above. Examples of the oxygen-containing gas include the compound (O) described above. The compound (III) described above can be used as a starting material effectively for introducing a group III atom. Especially B
₂ H ₆ and BF ₃ are suitable.

The compound (V) described above can be effectively used as a starting material for introducing a group V atom. Particularly, PH ₃ and PF ₅ are suitable. The compound (VI) described above is effectively used as a starting material for introducing a Group VI atom. A deposition method preferably used as a plasma CVD method is RF plasma CVD.
And a microwave plasma CVD method. When depositing by RF plasma CVD, capacitively coupled RF plasma C
The VD method is suitable.

When depositing by the RF plasma CVD method,
The substrate temperature in the deposition chamber is 100 to 450 ° C., and the internal pressure is 0.1
-10 Torr , RF power is 0.01-5.0 W / c
The optimum conditions for m ² and the deposition rate are 0.1 to 30 ° / sec. 1 MHz to 10 as RF frequency
0 MHz is a suitable range, and a frequency near 13.56 MHz is particularly optimum.

The compounds capable of being gasified are H ₂ , H
It may be appropriately diluted with a gas such as e, Ne, Ar, Xe, or Kr and introduced into the deposition chamber. In particular, μc-Si: H, μc-
SiC: H, μc-Si: HX, μc-SiC: HX,
μc-SiO: H, μc-SiN: H, μc-SiO
N: HX, μc-SiOCN: HX, poly-Si:
H, poly-Si: HX, poly-SiC: H, p
poly-SiC: HX, poly-Si, poly-S
iC: H, a-SiC: H, a-SiC: HX, a-S
iO: H, a-SiN: H, a-SiON: HX, a-
When depositing a microcrystalline layer, a polycrystalline layer, or an amorphous layer having a wide band gap, such as SiOCN: HX, which has low light absorption, dilute the source gas by 2 to 100 times with hydrogen gas,
Preferably, the F power introduces a relatively high power.

In the case of depositing by a microwave plasma CVD method, a method of introducing a microwave into a deposition chamber through a waveguide through a dielectric window is suitable for a microwave plasma CVD apparatus. Although a deposition film forming method optimal for forming an i-type layer is also a suitable deposition method, a deposition film applicable to a photovoltaic element can be formed under a wider range of deposition conditions. That is, the substrate temperature in the deposition chamber is 100 to 400 ° C., and the internal pressure is 0.5 to 30.
mTorr, microwave power is 0.005 to 1 W / c
m ³ and the frequency of the microwave are preferably 0.5 to 10 GHz.

The compounds capable of being gasified are H ₂ , H
It may be appropriately diluted with a gas such as e, Ne, Ar, Xe, or Kr and introduced into the deposition chamber. In particular, μc-Si: H, μc-
SiC: H, μc-Si: HX, μc-SiC: HX,
μc-SiO: H, μc-SiN: H, μc-SiO
N: HX, μc-SiOCN: HX, poly-Si:
H, poly-Si: HX, poly-SiC: H, p
poly-SiC: HX, poly-Si, poly-S
iC, H, a-SiC: H, a-SiC: HX, a-S
iO: H, a-SiN: H, a-SiON: HX, a-
When depositing a microcrystalline layer, a polycrystalline layer, or an amorphous layer having a wide band gap with low light absorption such as SiOCN: HX, dilute the source gas 2 to 100 times with hydrogen gas and compare the microwave power. It is preferable to introduce extremely high power.

I-Type Layer (106, 125) In the photovoltaic device of the present invention, the i-type layer is the most important layer that generates and transports carriers with respect to irradiation light.
As the i-type layer, a slightly p-type and slightly n-type layer can be used. The i-type layer of the photovoltaic element of the present invention contains silicon atoms and carbon atoms, and the band gap changes smoothly in the layer thickness direction of the i-type layer. It is shifted from the center position of the layer in the direction of the p / i interface (i / p interface).
Further, it is preferable that a valence electron controlling agent serving as a donor and a valence electron controlling agent serving as an acceptor are both doped.

Hydrogen atoms (H, D) or halogen atoms (X) contained in the i-type layer work to compensate for dangling bonds of the i-type layer, and the mobility and lifetime of carriers in the i-type layer. To improve the product of It also works to compensate for the interface states at the p / i interface (i / p interface) and the i / Si interface (Si / i interface), improving the photovoltaic power, photocurrent and photoresponsiveness of the photovoltaic element. It has the effect of causing. Hydrogen atoms and / or halogen atoms contained in the i-type layer are 1 to 3
0 at% is mentioned as the optimum content.

In particular, the p / i interface (i / p interface), i / S
A preferred distribution form includes a large distribution of the content of hydrogen atoms and / or halogen atoms near the i interface (Si / i interface), and the content of hydrogen atoms and / or halogen atoms near the interface. Is preferably in the range of 1.1 to 2 times the content in the bulk.
Further, it is preferable that the content of hydrogen atoms and / or halogen atoms is changed in contrast to the increase and decrease of the content of silicon atoms. Where the content of silicon atoms is the largest, the content of hydrogen atoms or / halogen atoms is 1 to
A preferred range is 10 at%, and a preferred range is 0.3 to 0.8 times the maximum region of the content of hydrogen atoms and / or halogen atoms.

In the i-type layer of the photovoltaic element of the present invention, it is desirable that the content of hydrogen atoms and / or halogen atoms be small where there are many silicon atoms and large where there are few silicon atoms. That is , corresponding to the band gap, the content of hydrogen atoms and / or halogen atoms is small where the band gap is narrow, and the content of hydrogen atoms and / or halogen atoms is large where the band gap is wide.
And the content of halogen atoms is desirably increased. There is not known details of the mechanism, but have you to the deposited film forming method deposition of alloys based semiconductor containing silicon atoms and carbon atoms according to the present invention, respectively by the ionization rate of the silicon atoms and carbon atoms Difference It is considered that there is a difference in the RF energy obtained by the atoms, and as a result, even if the hydrogen content or / halogen content in the alloy-based semiconductor is small, the relaxation is sufficiently advanced and a good-quality alloy-based semiconductor can be deposited.

In addition, by adding a small amount of 100 ppm or less of oxygen and / or nitrogen to the i-type layer containing silicon atoms and carbon atoms, the photovoltaic element has good durability against annealing due to long-term vibration. It becomes. Although the details of the cause are unknown, the composition ratio of silicon atoms and carbon atoms changes continuously in the layer thickness direction, so that silicon atoms and carbon atoms are mixed at a fixed ratio. It is considered that the residual strain also tends to increase. By adding oxygen atoms and / or nitrogen atoms to such a system, the structural strain can be reduced, and as a result, the durability of the photovoltaic element against annealing due to long-term vibration is improved. it is conceivable that. As the distribution of oxygen atoms and / or nitrogen atoms in the layer thickness direction, a distribution that increases and decreases in accordance with the content of silicon atoms is preferable. This distribution is opposite to the distribution of hydrogen atoms and / or halogen atoms, but such a distribution is considered preferable in consideration of the effect of removing structural distortion and the effect of reducing terminal bonds. .

Further, by distributing such hydrogen atoms (or / and halogen atoms) and oxygen atoms (or / and nitrogen atoms), tail states of the valence band and the conduction band are smoothly and continuously connected. It is. i
The layer thickness of the mold layer greatly depends on the structure of the photovoltaic element (for example, single cell, tandem cell, triple cell) and the band gap of the i-type layer. Can be

The i-type layer containing silicon atoms and carbon atoms by the above-described method for forming a deposited film has a deposition rate of 2.5 m.
Even if it is increased to n / sec or more, the tail state on the valence band side is small, and the inclination of the tail state is 60 m.
eV or less, and the density of terminal bonds by electron spin resonance (ESR) is 10 ¹⁷ / cm ³ or less. The band gap of the i-type layer is from the bulk toward the p / i interface (i / p interface) and / or the i / Si interface (Si / i interface).
It is preferable to design so as to increase toward the interface. By designing in this way, the photovoltaic power and photocurrent of the photovoltaic element can be increased,
Furthermore, it is possible to control a decrease (light deterioration) in the photoelectric conversion efficiency when irradiated with light for a long time.

Si Layer (105, 126) In the photovoltaic device of the present invention, the Si layer is an important layer for efficiently transporting generated carriers. As the conductivity type of the Si layer, an i-type layer, slightly p-type, and slightly n-type can be used. As shown in FIGS. 1A and 1B, only between the n-type layer and the i-type layer or between the i-type layer and the second n-type layer,
If there is a layer, it is good to be i-type or slightly n-type. Further, as shown in FIG. 19, between the n-type layer and the i-type layer and in the second
When there is a Si layer between both the p-type layer and the i-type layer, the conductivity type of the former Si layer (first Si layer) is preferably i-type or slightly n-type, and It is desirable that the conductivity type of the Si layer (second Si layer) be i-type or slightly p-type.

As the Si layer of the photovoltaic device of the present invention,
A-Si: H, a-S containing silicon atoms
i: HX, a-SiGe: H, a-SiGe: HX, a
-SiO: H, a-SiN: H, a-SiON: HX, etc. are mentioned, and a-Si: H and a-Si: HX are most suitable. Hydrogen atoms (H, D) or halogen atoms (X) contained in the Si layer work to compensate for the dangling bonds of the Si layer and improve the product of the carrier mobility and the lifetime in the Si layer. It is. In addition, i / Si interface (Si / i interface), S
It functions to compensate the interface order of each interface of the i / n interface (n / Si interface), and has an effect of improving the photovoltaic power, photocurrent and photoresponsiveness of the photovoltaic element. Hydrogen atoms and / or halogen atoms contained in the Si layer are 1 to 3
0 at% is mentioned as the optimum content.

In particular, in the Si layer near the i / Si interface (Si / i interface) and near the Si / n interface (n / Si interface), the one in which the content of hydrogen atoms and / or halogen atoms is large is distributed. The content of hydrogen atoms and / or halogen atoms in the vicinity of the interface is preferably 1.1 to 2 times the content of bulk hands. Further, it is preferable that the content of hydrogen atoms and / or halogen atoms is changed in contrast to the increase and decrease of the content of silicon atoms. The content of the hydrogen atom and / or the halogen atom at the maximum content of the silicon atom is preferably 1 to 10 at%,
A preferred range is 0.3 to 0.8 times the maximum region of the content of hydrogen atoms and / or halogen atoms.

In addition, oxygen and / or nitrogen are added to the Si layer by 1%.
Addition of not more than 00 ppm improves the durability of the photovoltaic element against annealing due to long-term vibration. Although the details of the cause are unclear, the composition ratio of the i-type layer containing silicon atoms and carbon atoms and the second p-type layer (p-type layer) are rapidly different. It is considered that the residual strain tends to increase. By adding oxygen atoms and / or nitrogen atoms to such a system, the structural strain can be reduced, and as a result, the durability of the photovoltaic element against annealing due to long-term vibration is improved. it is conceivable that. The distribution of oxygen atoms and / or nitrogen atoms in the layer thickness direction is as follows: i / Si interface (Si / i interface)
A distribution that decreases toward the i / n interface (n / Si interface) is preferred.

Further, by distributing such hydrogen atoms (or / and halogen atoms) and oxygen atoms (or / and nitrogen atoms), tail states of the valence band and the conduction band are smoothly and continuously connected. It is. S
The thickness of the i-layer is an important factor in the photovoltaic device of the present invention, and the optimum thickness is 30 nm or less.

The deposition rate of the Si layer is an important factor in the photovoltaic device of the present invention, and the optimal deposition rate is 2 nm / sec or less. Further, as a method for depositing the Si layer, an RF plasma CVD method is optimal, but an optical CVD method can also be used. When the Si layer is deposited using the RF plasma CVD method, a capacitively coupled RF plasma CV
Method D is suitable.

When depositing by the RF plasma CVD method,
The substrate temperature in the deposition chamber is 100 to 450 ° C., and the internal pressure is
0.1 to 10 Torr, RF power is 0.005 to
0.1 W / cm ² is mentioned as an optimum condition. An RF frequency of 1 MHz to 100 MHz is a suitable range, and a frequency near 13.56 MHz is particularly optimal.

As the raw material gas, specifically, the above-mentioned compound (Si) is mentioned as a gasizable compound containing a silicon atom. Examples of the gasizable compound containing a germanium atom include the compound (Ge) described above.
Is mentioned. Examples of the nitrogen-containing gas include the compound (N) described above.

Examples of the oxygen-containing gas include the compound (O) described above. The substance to be introduced to conductivity type slightly p-type include periodic table Group III element, the material introduced to conductivity type slightly n-type periodic table V group atoms or may include / and group VI atoms. Compounds that can be effectively used as starting materials for introducing Group III atoms include the compounds (II) described above.
I). In particular , B ₂ H ₆ and BF ₃ are suitable.

The compound (V) described above can be effectively used as a starting material for introducing a group V atom. Particularly, PH ₃ and PF ₆ are suitable. The compound (VI) described above is effectively used as a starting material for introducing a Group VI atom. Further, the gasifiable compound may be appropriately diluted with a gas such as H ₂ , He, Ne, Ar, Xe, or Kr and introduced into the deposition chamber.

When the Si layer is deposited by the photo-CVD method, the substrate temperature in the deposition chamber is 100 to 450 ° C., the internal pressure is 0.1 to 10 Torr, and the light source is a low-pressure mercury lamp or an ArF excimer laser. Alternatively, the deposition rate may be increased by introducing a very small amount of mercury (Hg) into the deposition chamber. As the raw material gas, specifically, as a gasizable compound containing a silicon atom,
The compound (Si) described above is exemplified. In this case, when a low-pressure mercury lamp is used as a light source, a high-order silane, for example, Si ₂ H ₆ , Si ₂ H _n X _6-n (X: halogen) is suitable.

Examples of the gasizable compound containing a germanium atom include the compound (Ge) described above. In this case, when a low-pressure mercury lamp is used as a light source,
Higher germanes such as Ge ₂ H ₆ are suitable. Examples of the nitrogen-containing gas include the compound (N) described above. Examples of the oxygen-containing gas include the compound (O) described above.

[0152] As the material introduced to conductivity type slightly p-type include periodic table Group III element atoms, periodic as a substance to be introduced to conductivity type slightly n-type Table V group atoms or / and group VI atoms are listed. Compounds that can be effectively used as starting materials for introducing Group III atoms include the compounds (III) described above.
Can be mentioned. In particular , B ₂ H ₆ and BF ₃ are suitable.

The compound (V) described above can be effectively used as a starting material for introducing a group V atom. Particularly, PH ₃ and PF ₅ are suitable. The compound (VI) described above is effectively used as a starting material for introducing a Group VI atom. Further, the gasifiable compound may be appropriately diluted with a gas such as H ₂ , He, Ne, Ar, Xe, or Kr and introduced into the deposition chamber.

In the Si layer of the present invention, the tail state on the valence band side is small, and the inclination of the tail state is 5%.
5ME V or less, the density of the bond end by either One electron spin resonance (ESR) is 10 ¹⁷ / cm ³ or less. The peak width at 2000 cm ⁻¹ representing the state in which one hydrogen atom is bonded to the silicon atom of the Si layer of the present invention is preferably small.

Transparent Electrodes (108, 128) As the transparent electrode, a transparent electrode of indium oxide or indium-tin oxide is suitable. For deposition of the transparent electrode, a sputtering method and a vacuum deposition method are the most suitable deposition methods.
The transparent electrode is deposited as follows.

In a sputtering apparatus, indium
When depositing a transparent electrode made of oxide on a substrate,
Get is metal indium (In) or indium oxide
(In _TwoO_Three) Is used. More Inn
Depositing a transparent electrode consisting of di-tin oxide on a substrate
Target is metallic tin, metallic indium or gold
Alloy of tin and metal indium, tin oxide, indium
Targets such as oxides of oxide and indium-tin oxide
Used in any combination.

When depositing by sputtering, the substrate temperature is an important factor, and a preferred range is from 25 ° C. to 600 ° C. Also, when depositing a transparent electrode by a sputtering method, as a sputtering gas,
An inert gas such as an argon gas (Ar), a neon gas (Ne), a xenon gas (Xe), a helium gas (He), and the like are preferable, and an Ar gas is particularly preferable. It is preferable to add oxygen gas (O ₂ ) to the inert gas as needed. Particularly when a metal is targeted, oxygen gas (O ₂ ) is essential.

Further, when sputtering the target with the above-mentioned inert gas or the like, the pressure in the discharge space is set to 0.1 to 50 mTorr in order to perform sputtering effectively.
Is a preferred range. In addition, as a power source in the case of the sputtering method, a DC power source and an RF power source are suitable. A suitable range for the electric power during sputtering is 10 to 1000 W.

The deposition rate of the transparent electrode depends on the pressure in the discharge space and the discharge power.
It is in the range of 1 to 10 nm / sec. It is preferable that the transparent electrode is deposited under such conditions that the thickness of the antireflection film is satisfied. As a specific layer thickness of the transparent electrode, a preferable range is 50 to 300 nm.

Examples of a deposition source suitable for depositing a transparent electrode in a vacuum deposition method include metal tin, metal indium, and indium-tin alloy. The substrate temperature when depositing the transparent electrode is preferably in the range of 25 ° C. to 600 ° C. Further, when depositing the transparent electrode, the pressure of the deposition chamber is reduced to 10 ^-6 Torr or less, and then oxygen gas (O
₂ ) needs to be introduced into the deposition chamber in the range of 5 × 10 ⁻⁵ Torr to 9 × 10 ⁻⁴ Torr.

By introducing oxygen in this range, the metal vaporized from the evaporation source reacts with oxygen in the gas phase to deposit a good transparent electrode. Alternatively, plasma may be generated by introducing RF power at the degree of vacuum, and vapor deposition may be performed via the plasma. The preferable range of the deposition rate of the transparent electrode under the above conditions is 0.01 to 10 nm / sec.
c. When the deposition rate is less than 0.01 nm / sec, the productivity is reduced. When the deposition rate is more than 10 nm / sec, the film becomes a coarse film, and the transmittance, the conductivity and the adhesion are reduced.

Back electrodes (101, 121) Ni, Au, Ti, Pd, Ag, A
Metals such as l, Cu, and AlSi, which have high reflectivity from visible light to near infrared and can form a good ohmic contact with silicon, or alloys thereof are suitable. These metals are desirably formed by a vacuum deposition method, a sputtering method, a plating method, a printing method, or the like.

For example, when forming by a vacuum evaporation method, n
Ti-Ag or Ti-Pd
-Ag or Ti-Ni-Cu is suitable, and Al is suitable for a p-type silicon substrate. In the case of forming by a plating method, Ni, Al, or Cr is suitable. Further, by performing a sintering process at 300 ° C. to 800 ° C. after the plating process, a better ohmic contact can be obtained, and Can reduce the interface state existing at the interface. In order to lower the series resistance of the electrode, Cu may be finally plated.

In the case of forming by a printing method, an Ag paste is printed on an n-type silicon substrate, and an Al paste is printed on a p-type silicon substrate by a screen printing machine, and then sintering is performed. Get contact.
The layer thickness of these metals is 10 nm to 5000 nm.
Is a suitable layer thickness. In order to make the surface of the back electrode uneven (texture), the temperature of the substrate at the time of deposition is set to 200 ° C. or more in the case of the vacuum deposition method, and after the back electrode is deposited in the case of the plating method or the printing method. The thermal annealing may be performed at a substrate temperature of 200 ° C. or higher.

Collector electrode (109, 129) The material and formation method of the collector electrode are basically the same as those of the back electrode. However, the photovoltaic layer i
In order to efficiently make light incident on the mold layer and efficiently collect generated carriers on the electrode, the shape (the shape as viewed from the light incident direction) and the material of the current collecting electrode are important.

Usually, the shape of the current collecting electrode is a comb shape, and the line width and the number of lines are determined by the shape and size of the photovoltaic element viewed from the light incident direction, the material of the current collecting electrode, and the like. Is done. The line width is usually about 0.1 mm to 5 mm. As a material, Ag, Cu, Al, Cr, or the like having a small specific resistance is usually used. Next, the power generation system of the present invention will be described with reference to the drawings.

A system using the photovoltaic device of the present invention comprises a photovoltaic device of the present invention, and the voltage and / or current of the photovoltaic device is monitored to supply the photovoltaic device to a storage battery and / or an external load. The control system includes a control system that controls the supply of power from a power element, and a storage battery that stores power from the photovoltaic element and / or supplies power to an external load.

FIG. 18 shows an example of a power supply system according to the present invention, which is a basic circuit for charging and supplying power using a photovoltaic element. In this circuit, the photovoltaic element of the present invention is used as a solar cell module, and a backflow prevention diode (C
D), a voltage control circuit (constant voltage circuit) for monitoring the voltage and controlling the voltage, a storage battery, a load, and the like.
Germanium diodes, silicon diodes, Schottky diodes, and the like are suitable as backflow prevention diodes. As storage batteries, nickel cadmium batteries,
Rechargeable silver oxide batteries, lead-acid batteries, flywheel energy storage units, and the like.

[0169] Voltage control circuit, until the battery is fully charged but approximately equal to the output of the solar cell, at a fully charged, the charging current by the charging control IC is stopped. Such a solar cell system using photovoltaic power can be used as a power source for a battery charging system for automobiles, a battery charging system for ships, a streetlight lighting system, an exhaust system, and the like.

As described above, the power supply system using the photovoltaic element of the present invention as a solar cell can be used stably for a long period of time, and even when the irradiation light applied to the solar cell fluctuates. Since it functions sufficiently as an electromotive element, it shows excellent stability.

[0171]

EXAMPLES Hereinafter, the electromotive force element of the present invention will be described in detail by manufacturing a solar cell, but the present invention is not limited to this. (Example 1) First, to prepare the solar cell of FIG. 1-a using an n-type polycrystalline silicon substrate fabricated by Cass pos- sesses method.

A substrate having a size of 50 × 50 m ² and a thickness of 500 μm was immersed in an aqueous solution of HF and HNO ₃ (diluted to 10% with H ₂ O) for several seconds and washed with pure water. Next, ultrasonic cleaning with acetone and Lee Sopuro <br/> propanol, further washed with pure water, dried hot air. Next, a source gas supply device 2000 shown in FIG.
And a deposition apparatus 400, a semiconductor layer was formed on the substrate by a manufacturing apparatus using a glow discharge decomposition method. less than,
The manufacturing procedure will be described.

In the gas cylinders 2041 to 2047 in FIG.
Is a raw material gas for producing the photovoltaic device of the present invention.
Sealed, 2041 is SiH_FourGas (purity 99.
999%) cylinder, 2042 CH_FourGas (purity 99.
9999%) cylinder, 2043 is H_TwoGas (purity 99.
9999%) cylinder, 2044 is H_Two100pp with gas
PH diluted to m_ThreeGas (99.99% purity, below
"PH_Three/ H_TwoCylinder), 2045 is H_Two
B diluted to 100 ppm with gas_TwoH₆Gas (purity 9
9.99%, hereinafter referred to as "B_TwoH₆/ H_TwoAbbreviated)
H, 2046 is H _TwoNH diluted to 1% with gas_Threegas
(Purity 99.9999%, hereinafter referred to as "NH_Three/ H_Two"
B) The cylinder, 2047, was diluted to 1% with He gas
O_TwoGas (purity 99.9999%, hereinafter "O_Two/ He "
(Abbreviated as). In advance, the gas cylinder 2041
When installing ~ 2047, each gas was
Introduce into the gas pipe from 02 to 2027 and adjust the pressure
Each gas pressure is set to 2 kg / cm by vessels 2031-2037.
^TwoWas adjusted.

Next, the back surface of the substrate 404 is
05, the leak valve 409 of the deposition chamber 401 is closed, the conductance valve 407 is fully opened, the interior of the deposition chamber 401 is evacuated by a vacuum pump (not shown), and the vacuum gauge 402 reads about 1 × 10 ^−4. valve 2001-2007 they become Torr, opening the auxiliary valve 408, the valve 200 when the internal gas pipe were evacuated, vacuum gauge 402 reading was about 1 × 10 ^-4 Torr again
1 to 2007 are closed, 2031 to 2037 are gradually opened, and each gas is supplied to the mass flow controller 2011 to 2011.
2071.

After the preparation for film formation is completed as described above, the substrate is subjected to a hydrogen plasma treatment.
A first p-type layer, an n-type layer, a Si layer, an i-type layer, and a second p-type layer were formed thereon. First, to perform the hydrogen plasma treatment, the valve 2003 was gradually opened, H ₂ gas was introduced into the deposition chamber 401, and the mass flow controller 2013 adjusted the H ₂ gas flow rate to 500 sccm. The conductance valve is adjusted while watching the vacuum gauge 402 so that the pressure in the deposition chamber becomes 2.0 Torr, and the heater 4 is adjusted so that the temperature of the substrate 404 becomes 550 ° C.
05, and confirm that the shutter 415 is closed when the substrate temperature is stabilized.
W) The power supply was set to 0.20 W / cm ³ , a μW power was introduced, glow discharge was generated, the shutter 415 was opened, and the hydrogen plasma treatment of the substrate was started. After 10 minutes, the shutter was closed, the μW power supply was turned off, the glow discharge was stopped, and the hydrogen plasma treatment was completed. After continuously flowing H ₂ gas into the deposition chamber 401 for 5 minutes, the valve 20
03 was closed, and the inside of the deposition chamber 401 and the inside of the gas pipe were evacuated.

Next, to form the first p-type layer, the valve 2003 was gradually opened, H ₂ gas was introduced into the deposition chamber 401, and the mass flow controller was adjusted so that the H ₂ gas flow rate became 50 sccm. Adjusted in 2013. Pressure in the deposition chamber was adjusted with conductance valve while watching the vacuum gauge 402 to be 2.0 Torr, and setting the heater 405 so that the temperature of the substrate 404 is 350 ° C., further where the substrate temperature became stable Valve 200
1, 2005, gradually open, SiH ₄ gas, B ₂ H ₆ /
H ₂ gas was introduced into the deposition chamber 401. At this time, Si
H ₄ gas flow rate is 5 sccm, H ₂ gas flow rate is 100 sccc
m and each of the mass flow controllers were adjusted so that the flow rate of the B ₂ H ₆ / H ₂ gas was 500 sccm. The opening of the conductance valve 407 was adjusted while watching the vacuum gauge 402 so that the pressure in the deposition chamber 401 became 2.0 Torr. After confirming that the shutter 415 is closed, the RF power supply is set to 0.20 W / cm ³ , RF power is introduced, and glow discharge is generated.
Was opened to start forming a first p-type layer on the substrate. Close the shutter was to prepare a first p-type layer having a thickness of 100 nm, turn off the RF power, stop the glow discharge to complete the formation of the first p-type layer. By closing the valve 2001,2005, SiH ₄ gas into the deposition chamber 401, B ₂ H ₆ / H ₂ gas and stopper influx, sedimentary H ₂ gas was <br/> 5 minutes flow into the volume chamber 401 After continuing, the valve 2003 was closed, and the inside of the deposition chamber 401 and the inside of the gas pipe were evacuated.

To form the n-type layer, the auxiliary valve 40
8. Open the valve 2003 gradually, introduce H ₂ gas into the deposition chamber 401 through the gas introduction pipe 411, set the mass flow controller 2013 so that the H ₂ gas flow rate becomes 50 sccm, and set the pressure in the deposition chamber to 1 0.0Torr
r with the conductance valve so that the substrate 4
Heater 405 so that the temperature of 04 becomes 350 ° C.
It was set. When the substrate temperature was stabilized, the valves 2001 and 2004 were gradually opened to open SiH ₄ gas and P
H ₃ / H ₂ gas was caused to flow into the deposition chamber 401. At this time,
SiH ₄ gas flow rate ₂ sccm, H ₂ gas flow rate 100 s
Each of the mass flow controllers was adjusted so that the flow rate of ccm and PH ₃ / H ₂ gas became 200 sccm. The opening of the conductance valve 407 was adjusted so that the pressure in the deposition chamber 401 became 1.0 Torr. The power of the RF power source is set to 0.01 W / cm ³ , RF power is introduced to the RF electrode 410, a glow discharge is generated, a shutter is opened, and formation of an n-type layer on the first p-type layer is started. and closes the shutter was to prepare a n-type layer having a thickness of 30 nm, turn off the RF power, stop the glow discharge to complete the formation of the n-type layer. By closing the valve 2001,2004, SiH ₄ gas into the deposition chamber 401, PH ₃ / H ₂ gas flow into the <br/> and stopper of continued flow compost H ₂ gas for 5 minutes into a product chamber 401
After closing the outflow valves 2003, it was evacuated deposition chamber 及 beauty gas pipe 401.

To form the Si layer, the valve 2003 is gradually opened, H ₂ gas is introduced into the deposition chamber 401 through the introduction pipe 411, and the mass flow controller 2013 is set so that the H ₂ gas flow rate becomes 50 sccm. Then, the pressure in the deposition chamber was adjusted with a conductance valve so as to be 1.5 Torr, and the heater 405 was set so that the temperature of the substrate 404 was 270 ° C. When the substrate temperature was stabilized, the valve 2001 was further opened gradually, and SiH ₄ gas was introduced into the deposition chamber 401. At this time, the flow rate of the SiH ₄ gas was ₂ sccm, and the flow rate of the H ₂ gas was 10 sccm.
Each mass flow controller was adjusted to be 0 sccm. The pressure in the deposition chamber 401 is 1.5 Torr
The opening of the conductance valve 407 was adjusted to be r. The power of the RF power source was set to 0.01 W / cm ³ , RF power was introduced to the RF electrode 410 to generate glow discharge, the shutter was opened, the formation of a Si layer on the n-type layer was started, and the deposition rate was increased. 0.15 nm / sec, layer thickness 10 n
Close the shutter was to prepare a Si layer of m, RF
The power was turned off, the glow discharge was stopped, and the formation of the Si layer was completed. When the valve 2001 is closed, the Si
H ₄ gas and stopper the flow rate of the H ₂ gas into the sedimentary chamber 401 5 minutes
After it continued to flow during closing the outflow valves 2003, deposition chamber 4
It was evacuated 及 beauty gas in the pipe 01.

Next, in order to form an i-type layer, the valve 20 was used.
03 was gradually opened, H ₂ gas was introduced into the deposition chamber 401, and the mass flow controller 2013 adjusted the H ₂ gas flow rate to 300 sccm. The pressure in the deposition chamber was adjusted with conductance valve to be 0.01 Torr, and setting the heater 405 so that the temperature is 350 ° C. of the substrate 404, further valves <br/> substrate temperature was stabilized 2001 , 2002, gradually open, S
iH ₄ gas and CH ₄ gas were caused to flow into the deposition chamber 401.
At this time, SiH ₄ gas flow rate of 100 sccm, CH ₄ gas flow rate 30 sccm, H ₂ gas flow rate was adjusted with mass flow controllers each so that 300 sccm. The opening of the conductance valve 407 was adjusted so that the pressure in the deposition chamber 401 became 0.01 Torr. Next , the power of the RF power supply 403 was set to 0.40 W / cm ³ and applied to the RF electrode 403. Thereafter, μW (not shown)
Set the power of the power supply to 0.20 W / cm ³ and set the dielectric window 4
The power of μW was introduced into the deposition chamber 401 through 13 to generate glow discharge, the shutter was opened, and the formation of an i-type layer on the Si layer was started. Using a computer that is connected to a mass flow controller, SiH ₄ gas, the flow rate of CH ₄ gas is varied according to the flow rate change pattern shown in FIG. 5, shutter <br/> terpolymer in were manufactured i-type layer of thickness 300nm Is closed, the glow discharge is stopped by turning off the μW power supply, and RF
The power supply 403 was turned off, and the fabrication of the i-type layer was completed. Valve 20
01, 2002, and SiH ₄ into the deposition chamber 401.
Gas, CH ₄ gas and stopper influx, after continued to flow compost 5 minutes H ₂ gas into the product chamber 401, closing the valve 2003 was evacuated deposition chamber and the gas in the pipe 401.

Next, in order to form a second p-type layer, the valve 2003 was gradually opened, H ₂ gas was introduced into the deposition chamber 401, and the mass flow controller was adjusted so that the H ₂ gas flow rate became 50 sccm. Adjusted in 2013. A pressure in the deposition chamber was adjusted with conductance valve to be 2.0 Torr, and setting the heater 405 so that the temperature of the substrate 404 is 200 ° C., the substrate temperature was stabilized
At this time , the valves 2001, 2002, and 2005 were gradually opened, and SiH ₄ gas, CH ₄ gas, and B ₂ H ₆ / H ₂ gas flowed into the deposition chamber 401. At this time, the flow rate of the SiH ₄ gas is 1 sccm, and the flow rate of the CH ₄ gas is 0.5 scc.
m, H ₂ gas flow rate is _{100sccm, B 2 H 6 / H} 2 gas flow rate were adjusted in each mass flow controllers such that the 100 sccm. The pressure in the deposition chamber 401 is 2.0
The opening of the conductance valve 407 was adjusted to be Torr. The RF power was set to 0.20 W / cm ³ , RF power was introduced, glow discharge was generated, the shutter 415 was opened, and the formation of the second p-type layer on the i-type layer was started. When the second p-type layer having a thickness of 10 nm was formed, the shutter was closed, the RF power was turned off, glow discharge was stopped, and the formation of the second p-type layer was completed. Valves 2001 and 2
002 , 2005 is closed and SiH into the deposition chamber 401 is closed.
₄ gas, CH ₄ gas, B ₂ H ₆ / H ₂ gas and stopper influx, after continued to flow compost <br/> H ₂ gas for 5 minutes into a product chamber 401, closing the valve 2003, the deposition chamber 401 The inside and the gas pipe are evacuated, the auxiliary valve 408 is closed, and the leak valve 409
Was opened, and the deposition chamber 401 was leaked.

Next, as a transparent electrode, ITO (In ₂ O ₂ + SnO ₂ ) having a thickness of 70 nm was vacuum-deposited on the second p-type layer by a usual vacuum deposition method. Then, a collector electrode layer thickness 5μm composed of silver (Ag) on the transparent electrode was vacuum deposited by conventional vacuum deposition method. Next , a 3 μm-thick back electrode made of an Ag—Ti alloy was vacuum-deposited on the back surface of the substrate by a normal vacuum deposition method.

Thus, the production of this solar cell has been completed. This solar cell is referred to as (SC Ex. 1), and Table 1 shows conditions for forming the first p-type layer, the n-type layer, the Si layer, the i-type layer, and the second p-type layer. (Comparative Example 1-1) The same conditions as in Example 1 except that the SiH ₄ gas flow rate and the CH ₄ gas flow rate were adjusted by the respective mass flow controllers according to the flow rate patterns shown in FIG. 6 when forming the i-type layer. A solar cell was manufactured in the same procedure. This solar cell is referred to as (SC ratio 1-1).

(Comparative Example 2) In forming an i-type layer, μW
A solar cell was manufactured under the same conditions and in the same procedure as in Example 1 except that the power was changed to 0.5 W / cm ³ . This solar cell is referred to as (SC ratio 1-2). In forming (Comparative Example 1-3) i-type layer, except that the RF power to 0.15 W / cm ^3, the same conditions as in Example 1, to prepare the solar cell by the same procedure. This solar cell is referred to as (SC ratio 1-3).

(Comparative Example 1-4) In forming the i-type layer,
μW power of 0.5 W / cm ³ , RF power of 0.55 W /
A solar cell was manufactured under the same conditions and in the same procedure as in Example 1 except that the thickness was changed to cm ³ . This solar cell (SC ratio 1-4)
I will call it. (Comparative Example 1-5) A solar cell was fabricated under the same conditions and in the same procedure as in Example 1 except that the pressure in the deposition chamber was set to 0.08 Torr when forming the i-type layer. This solar cell is referred to as (SC ratio 1-5).

(Comparative Example 1-6) When forming a Si layer,
A solar cell was manufactured under the same conditions and in the same procedure as in Example 1 except that the deposition rate was 3 nm / sec. This solar cell is referred to as (SC ratio 1-6). (Comparative Example 1-7) When forming a Si layer, the layer thickness was set to 40 n.
A solar cell was manufactured under the same conditions and in the same procedure as in Example 1 except that the value was changed to m. This solar cell is referred to as (SC ratio 1-7).

The fabricated solar cells (SC Ex. 1) and (S
The initial light conversion efficiency (photovoltaic power / incident light power) and durability characteristics of C ratio 1-1) to (SC ratio 1-7) were measured.
For the measurement of the initial photoelectric conversion efficiency, the manufactured solar cell was
Installed under -1.5 (100 mW / cm ² ) light irradiation,
It is obtained by measuring V-1 characteristics. As a result of the measurement, the (SC ratio 1−
The initial photoelectric conversion efficiencies of 1) to (SC ratio 1-7) were as follows.

(SC ratio 1-1) 0.88 times (SC ratio 1-2) 0.63 times (SC ratio 1-3) 0.80 times (SC ratio 1-4) 0.65 times (SC ratio 1-5) 0.77 times (SC ratio 1-6) 0.70 times (SC ratio 1-7) 0.82 times The durability of the solar cell was measured at 70% humidity.
Installed in a dark place at a temperature of 60 ° C., with an amplitude of 0.3 at 3600 rpm.
After applying a vibration of 1 mm for 24 hours, AM1.5 (10
0 mW / cm ² ) The change in photoelectric conversion efficiency under irradiation (photoelectric conversion efficiency after endurance test / initial photoelectric conversion efficiency) was determined. As a result of the measurement, for the solar cell of (SC Ex. 1),
The durability characteristics of (SC ratio 1-1) to (SC ratio 1-7) were as follows.

(SC ratio 1-1) 0.89 times (SC ratio 1-2) 0.81 times (SC ratio 1-3) 0.72 times (SC ratio 1-4) 0.80 times (SC ratio) 1-5) 0.72 times (SC ratio 1-6) 0.73 times (SC ratio 1-7) 0.83 times Next, a stainless steel substrate and a barium borosilicate glass (7059 manufactured by Corning Co., Ltd.) substrate And the SiH ₄ gas flow rate and CH ₄ gas flow rate were set to the values shown in Table 2,
Under the same manufacturing conditions as in the i-type layer of Example 1, an i-type layer was formed on a substrate to a thickness of 1 μm to prepare a sample for measuring physical properties. These samples will be referred to as (SP1-1) to (SP1-7). The bandgap (Eg) and composition of the manufactured physical property measurement sample were analyzed, and the relationship between the composition ratio of Si (silicon) atoms and C (carbon) atoms and the bandgap was determined. The band gap was measured by placing a glass substrate on which an i-type layer was fabricated on a spectrophotometer (Model 330, manufactured by Hitachi, Ltd.) and measuring the wavelength dependence of the absorption coefficient of the i-type layer. The band gap of the i-type layer was determined by the method described on page 109 of Makoto Konagai (co-authored by Shokodo Co., Ltd.).

In the composition analysis, the stainless steel substrate on which the i-type layer was formed was placed on an Auger electron spectrometer (JAM manufactured by JEOL Ltd.).
P-3), the composition ratio of Si atoms to C atoms was measured. Table 2 and FIG. 7 show the results of band gap and composition analysis. Next, the composition analysis in the layer thickness direction of Si atoms and C atoms in the i-type layers of the manufactured solar cell (SC Ex. 1) and (SC Comp. 1-1) to (SC Comp. Was performed in the same manner as described above.

Next, a sample of a Si layer having a thickness of 1 μm was prepared, and the band gap was determined by the above method.
1.75 (eV). This sample is referred to as (SP1-
8). (SP1-1) to (SP1-
7), the change in the band gap in the thickness direction of the i-type layer and the Si layer was determined from the relationship between the composition ratio of Si atoms and C atoms and the band gap determined by (SP1-8). FIG. 8 shows the result. As can be seen from FIG. 8, (SC actual 1), (SC
In the solar cells of the ratios 1-2) to (SC ratio 1-7), the position of the minimum value of the band gap is p / p from the center position of the i-type layer.
It was found that the solar cell having a bias toward the i-interface direction (SC ratio 1-1) had the minimum value of the band gap offset toward the Si / i interface from the center of the i-type layer.

As described above, (SC actual 1), (SC ratio 1-1)
The change of the band gap in the layer thickness direction of (SC ratio 1-7) is caused by the source gas containing Si (in this case, SiH ₄ gas) and the source gas containing C (in this case, (CH ₄ gas). (Comparative Example 1-8) Several solar cells were manufactured in the same manner as in Example 1 except that the μW power and the RF power introduced when forming the i-type layer were variously changed. Figure 9 is a relationship μW power and the deposition rate, the deposition rate is independent of the RF power, constant in μW power 0.32 W / cm ³ or more, SiH ₄ gas and CH ₄ gas as a source gas in this power Is 1
It turned out to be 00% decomposed. AM1.5 (1
(00 mW / cm ² ) When the initial photoelectric conversion efficiency of the solar cell when irradiated with light was measured, the result shown in FIG. 10 was obtained. The curve in this figure is an envelope for showing the ratio of the initial photoelectric conversion efficiency of each solar cell when the initial photoelectric conversion efficiency of Example 1 is set to 1. As you can see from the figure,
The μW power is not more than the μW power (0.32 W / cm ³ ) for decomposing 100% of the SiH ₄ gas and the CH ₄ gas, and R
It was found that the initial photoelectric conversion efficiency was significantly improved when the F power was larger than the μW power.

(Comparative Example 1-9) Formation of i-type layer in Example 1
During the deposition, the flow rate of the gas introduced into the deposition chamber 401 is changed to SiH _Four
Gas 50 sccm, CH_FourChange to gas 10sccm,
H_TwoNo gas is introduced and various μW and RF power
Several solar cells were produced by changing. The other conditions were the same as in Example 1.
Same as. Relationship between deposition rate, μW power and RF power
As a result, the deposition rate was found to be the same as that of Comparative Example 1-8.
ΜW power is 0.18 W / cm, independent of force^ThreeAbove
With this μW power constant, the source gas SiH_Fourgas
And CH_FourYou can see that the gas is 100% decomposed
Was. Initial light of solar cell when irradiated with AM1.5 light
When the power conversion efficiency was measured, it showed the same tendency as in FIG.
Results. That is, μW power is SiH_FourGas
And CH_FourΜW power (0.18
W / cm^Three) Or less and RF power is greater than μW power
The initial photoelectric conversion efficiency is greatly improved.
won.

(Comparative Example 1-10) An i-type layer was formed in Example 1.
When forming, the flow rate of the gas introduced into the deposition chamber 401 is
_FourGas 200 sccm, CH_FourGas 50sccm, H_Two
The gas was changed to 500 sccm and the substrate temperature was 300
ΜW power by changing the setting of the heater to reach
And various RF powers to make several solar cells
Was. Other conditions were the same as in Example 1.

When the relationship between the deposition rate and the μW power and the RF power was examined, the deposition rate did not depend on the RF power and the μW power was constant at 0.65 W / cm ³ or more as in Comparative Example 1-8. With this electric power, the source gas SiH ₄ gas and C
It was found that H ₄ gas was decomposed 100%. A
When the initial photoelectric conversion efficiency of the solar cell when M1.5 light was irradiated was measured, the result showed the same tendency as in FIG. That is, the μW power is 100% of the SiH ₄ gas.
It was found that the initial photoelectric conversion efficiency was significantly improved when the power was less than the μW power (0.65 W / cm ³ ) to be decomposed and the RF power was larger than the μW power.

(Comparative Example 1-11) In forming the i-type layer in Example 1, the pressure in the deposition chamber was increased from 3 mTorr to 200 m.
Several solar cells were manufactured under the same conditions as in Example 1 except for various changes up to Torr. When the initial photoelectric conversion efficiency of the solar cell when irradiating AM1.5 light was measured, the result was as shown in FIG. 11 and the pressure was 50 mTorr.
At r or more, it was found that the initial photoelectric conversion efficiency was greatly reduced.

(Comparative Example 1-12) In forming the Si layer in Example 1, the deposition rate was changed variously by changing the flow rate of the SiH ₄ gas and the RF power, and the other conditions were the same as those in Example 1.
Some solar cells were produced in the same manner as described above. AM1.5
Measurement of the initial photoelectric conversion efficiency of the solar cell upon irradiation with light revealed that the initial photoelectric conversion efficiency was significantly reduced when the deposition rate of the Si layer was 2 nm / sec or more.

(Comparative Example 1-13) In forming the Si layer in Example 1, several solar cells were produced by changing the layer thickness variously and setting the other conditions to the same as in Example 1. When the initial photoelectric conversion efficiency of the solar cell when irradiating AM1.5 light was measured, it was found that the initial photoelectric conversion efficiency was greatly reduced when the layer thickness was 30 nm or more.

As described above, (Comparative Example 1-1) to (Comparative Example 1-1)
As seen in 3), the solar cell of this example (SC Ex. 1)
However, conventional solar cells (SC ratio 1-1) to (SC ratio 1-
It has been proved to have even better properties than 7). (Example 2) Band gap (Eg) in Example 1
Some solar cells were manufactured by changing the position of the minimum value in the layer thickness direction, the size of the minimum value, and the pattern, and the initial photoelectric conversion efficiency and the durability were examined in the same manner as in Example 1. At this time, the SiH ₄ gas flow rate of the i-type layer and CH ₄
Example 1 was the same as Example 1 except for the change pattern of the gas flow rate.
FIG. 12 shows a band diagram in the layer thickness direction of the solar cell when the change pattern of the SiH ₄ gas flow rate and the CH ₄ gas flow rate is changed. (SC Ex. 2-1) to (SC Ex. 2-5) are obtained by changing the position of the minimum value of the band gap with respect to the layer thickness direction, and according to (SC Ex. 2-1) to (SC Ex. 2-5), p
This is changed from the / i interface toward the i / Si interface. (SC Example 2-6) and (SC Example 2-7) are obtained by changing the minimum value of the band gap of (SC Example 2-1). (SC Ex. 2-8) to (SC Ex. 2-10) are obtained by changing the band pattern. Table 3 shows the results of examining the initial photoelectric conversion efficiency and durability characteristics of these manufactured solar cells (the values in the table are based on SC Example (2-1)). As can be seen from these results, the band gap of the i-type layer smoothly changes in the layer thickness direction regardless of the size and the change pattern of the minimum value of the band gap, and the position of the minimum value of the band gap is changed to the i-type layer. P / i from the center of
It was found that the solar cell of the present invention which was deviated in the interface direction was more excellent.

Example 3 A solar cell shown in FIG. 1A containing a valence electron controlling agent in a Si layer was produced. (Example 3-1) When forming a Si layer, SiH ₄ gas,
Except for flowing PH ₃ / H ₂ gas in 2sccm deposition chamber in addition to the H ₂ gas were the same as in Example 1. The manufactured solar cell (SC Ex. 3-1) is similar to (SC Ex. 1), and has better initial photoelectric conversion efficiency and durability than conventional solar cells (SC ratio 1-1) to (SC ratio 1-7). It has been found to have properties.

(Embodiment 3-2) When forming a Si layer, S
₂ sc of PH ₃ / H ₂ gas in addition to iH ₄ gas and H ₂ gas
cm, B ₂ H ₆ / H ₂ gas was the same as in Example 1 except that the gas was flowed into the 0.5 sccm deposition chamber. The manufactured solar cell (SC Ex. 3-2) has better initial photoelectric conversion efficiency and durability than the conventional solar cells (SC Comp. 1-1) to (SC Comp. 1-7), similarly to (SC Ex. 1). It has been found to have properties.

Example 4 A solar cell shown in FIG. 1-b was fabricated using a p-type polycrystalline silicon substrate. First on substrate
, A p-type layer, an i-type layer, a Si layer, and a second n-type layer were sequentially formed. Table 4 shows the forming conditions. When forming the i-type layer, the flow rate of the SiH ₄ gas and the flow rate of the CH ₄ gas are changed as shown in the pattern of FIG. 6 so that the minimum value of the band gap comes from the i / p interface. 0.15
nm / sec. The layers other than the substrate and the semiconductor layer were manufactured under the same conditions and the same method as in Example 1.

The manufactured solar cell (SC Ex. 4) is similar to the conventional solar cell (SC ratio 1-1) to (SC ex.
It was found that it had better initial photoelectric conversion efficiency and durability than the ratio 1-7). (Example 5) A solar cell having a maximum value of the band gap of the i-type layer near the p / i interface and a thickness of the region of 20 nm was manufactured. FIG. 13A shows a flow rate change pattern of the i-type layer.

[0203] A film was manufactured using the same conditions and the same method as in Example 1 except that the flow rate change pattern of the i-type layer was changed.
Next, the composition of the solar cell was analyzed in the same manner as in Example 1, and the change in the band gap in the layer thickness direction of the i-type layer was examined based on FIG. It became. The manufactured solar cell (SC Ex. 5) is similar to the conventional solar cell (SC Ex. 1-1) to (SC Ex.
It was found to have better initial photoelectric conversion efficiency and durability than 7).

(Comparative Example 5) There was a region having the maximum band gap near the p / i interface of the i-type layer, and several solar cells were manufactured with various thicknesses of the region.
Except for the thickness of the region, it was manufactured using the same conditions and the same method as in Example 5. When the initial photoelectric conversion efficiency and durability of the manufactured solar cell were measured, the thickness of the region was 1 nm or more,
At 30 nm or less, even better initial photoelectric conversion efficiency and durability than the solar cell of Example 1 (SC Ex. 1) were obtained.

(Embodiment 6) The band gap of the i-type layer has a maximum value near the i / Si interface, and the thickness of the region is 15
A solar cell having a thickness of nm was produced. FIG. 13C shows a flow rate change pattern of the i-type layer. Except for changing the flow rate change pattern of the i-type layer, it was manufactured using the same conditions and the same method as in Example 1. Next, the composition analysis of the solar cell was performed in the same manner as in Example 1, and the change in the band gap in the layer thickness direction of the i-type layer was examined based on FIG. 7, and the results as shown in FIG. 13-d were obtained. It became. The manufactured solar cell (SC Ex. 6) is the same as the conventional solar cell (SC ratio 1-1) to (SC ex.
It was found to have better initial photoelectric conversion efficiency and durability than ratio 17).

(Comparative Example 6) There was a region having the maximum band gap near the i / Si interface of the i-type layer, and several solar cells were manufactured with various thicknesses of the region.
Except for the thickness of the region, it was manufactured using the same conditions and the same method as in Example 6. When the initial photoelectric conversion efficiency and durability of the manufactured solar cell were measured, the thickness of the region was 1 nm or more,
At 30 nm or less, even better initial photoelectric conversion efficiency and durability than the solar cell of Example 1 (SC Ex. 1) were obtained.

Example 7 A first p-type layer was formed by a gas diffusion method, and when forming an i-type layer, a C ₂ H ₂ gas was used to produce a solar cell with a μW power varied. First, the O ₂ / He gas cylinder is hydrogen
BBr ₃ (purity 99.999%, hereinafter referred to as “BB
r ₃ / H ₂ called the gas ") is replaced with a cylinder, further CH ₄
The gas cylinder was replaced with a C ₂ H ₂ gas (99.99% purity) cylinder. When forming the first p-type layer, the substrate temperature is set to 85
The temperature was adjusted to 0 ° C., BBr ₃ / H ₂ gas was introduced into a 500 sccm deposition chamber, and B was diffused into the n-type substrate at an internal pressure of 10 Torr. When the junction depth reaches 300 nm, BBr ₃ /
Stopping the introduction of the H ₂ gas was continued to flow H ₂ gas for 5 minutes. To be <br/> et al, when forming the i-type layer, C ₂ H instead of CH ₄ gas
_Two gases were introduced and changed according to a flow pattern as shown in FIG. Further , the μW power was changed as shown in FIG. 14-b. Except for the first p-type layer and the i-type layer, the same conditions, the same method, and the same procedure as in Example 1 were used. The manufactured solar cell (SC Ex. 7), like (SC Ex. 1), had better initial photoelectric conversion efficiency and durability than the conventional solar cells (SC ratio 1-1) to (SC ratio 1-7). It was found to have

(Example 8) A solar cell having an i-type layer containing oxygen atoms was manufactured. In forming the i-type layer, O ₂ / He gas is supplied at 10 scc in addition to the gas flowing in the first embodiment.
m, the same conditions, the same method, and the same procedure as in Example 1 were used, except that they were introduced into the deposition chamber 401. The manufactured solar cell (SC Ex. 8) has better initial photoelectric conversion efficiency and durability than the conventional solar cells (SC ratio 1-1) to (SC ratio 1-7), similarly to (SC Ex. 1). It was found to have.

Further, the content of oxygen atoms in the i-type layer was determined by SI
As a result of examination by MS, it was contained almost uniformly, and 2 × 10 ¹⁹
(Pieces / cm ² ). (Example 9) A silicon solar cell having an i-type layer containing nitrogen atoms was produced. Example 1 When forming an i-type layer,
The same conditions, the same method, and the same procedure as in Example 1 were used except that NH ₃ / H ₂ gas was introduced into the deposition chamber 401 at a flow rate of 5 sccm in addition to the gas flowing in the step. The manufactured solar cell (SC Ex. 9) is the same as the conventional solar cell (SC Ex. 1) as in (SC Ex. 1).
-1) to (SC ratio 1-7) were found to have better initial photoelectric conversion efficiency and durability. Further, when the content of nitrogen atoms in the i-type layer was examined by SIMS, it was found to be almost uniform and to be 3 × 10 ¹⁷ (pieces / cm ² )
It turned out to be.

Example 10 A solar cell having an i-type layer containing oxygen atoms and nitrogen atoms was manufactured. When forming the i-type layer, the same conditions as in Example 1 except that O ₂ / He gas is introduced at 5 sccm, NH ₂ / H ₂ gas is introduced at 5 sccm, and the gas is introduced into the deposition chamber 401 in addition to the gas flowing in Example 1. The same method and the same procedure were used. The manufactured solar cell (SC Actual 1)
0) is a conventional solar cell (SC ratio 1) as in (SC actual 1).
-1) to (SC ratio 1-7) were found to have better initial photoelectric conversion efficiency and durability. Further, the contents of oxygen atoms and nitrogen atoms in the i-type layer were determined by SIMS.
As a result of the investigation, it was almost uniformly contained, each 1 ×
It was found to be 10 ¹⁹ (pieces / cm ² ) and 3 × 10 ¹⁷ (pieces / cm ² ).

(Example 11) A solar cell was manufactured in which the hydrogen content of the i-type layer was changed corresponding to the silicon content. The O ₂ / He gas cylinder was filled with SiF ₄ gas (purity 99.
When the i-type layer is formed by replacing the cylinder with a cylinder, FIG.
According to the flow pattern of 5-a, SiH ₄ gas, CH ₄
The flow rates of the gas and the SiF ₄ gas were changed. The change in the band gap in the layer thickness direction of this solar cell (SC Ex. 11) was determined in the same manner as in Example 1. Figure 15-b
Shown in

Further, the content of hydrogen atoms and silicon atoms was analyzed in the thickness direction using a secondary ion mass spectrometer. As a result, as shown in FIG. 15-c, it was found that the hydrogen atom content had a distribution in the layer thickness direction corresponding to the silicon atom content. This solar cell (SC actual 1)
When the initial photoelectric conversion efficiency and the durability characteristics of 1) were obtained, a conventional solar cell (SC ratio 1-
It was found to have better initial photoelectric conversion efficiency and durability than 1) to (SC ratio 1-7).

Example 12 When a semiconductor layer of the solar cell shown in FIG. 1 was formed by a manufacturing apparatus using the microwave plasma CVD method shown in FIG.
A solar cell (SC Ex. 12) was produced in the same manner and in the same procedure as in Example 1, except that H ₄ gas) and a carbon atom-containing gas (CH ₄ gas) were mixed at a distance of 1 m from the deposition chamber. It was found that the manufactured solar cell (SC Ex. 12) had better initial photoelectric conversion efficiency and durability than (SC Ex. 1).

Example 13 When forming an i-type layer, RF
A positive DC bias is applied to the electrode 410 and the RF power, D
A solar cell was manufactured in which the C bias and the μW power were changed as shown in FIG. The fabricated solar cell (SC Ex 13)
Is a conventional solar cell (SC ratio 1−
It was found to have better initial photoelectric conversion efficiency and durability than 1) to (SC ratio 1-7).

Embodiment 14 FIG. 17 was manufactured using the manufacturing apparatus of FIG. 4 using the microwave plasma CVD method of the present invention.
Was manufactured. The solar cell of FIG. 17 is obtained by adding a set of nip structures to the solar cell of FIG. 1, and includes a first p-type layer, an n-type layer, an i-type layer,
Are respectively a first p-type layer in FIG.
It corresponds to a second n-type layer, a second i-type layer, and a third p-type layer.

The substrate used was an n-type polycrystalline silicon substrate manufactured by a casting method. 50 × 50m
One surface of the m ² substrate was immersed in NaOH (diluted to 1% with H ₂ O) at a temperature of 100 ° C. for 5 minutes and washed with pure water.
When the surface immersed in NaOH was observed with a scanning electron microscope (SEM), irregularities having a pyramid structure were formed on the surface, and the substrate was textured (Textu).
red). Next, ultrasonic cleaning with acetone and isopropanol, and further cleaning with pure water,
It was dried with warm air.

A hydrogen plasma treatment is performed in the same procedure and in the same manner as in Example 1, to form a first p-type layer on the textured surface of the substrate, and further to form a first n-type layer and a first i-type layer. layer,
A second p-type layer, a second n-type layer, a Si layer, a second i-type layer,
Third p-type layers were sequentially formed. When forming the second i-type layer, the flow rate of the SiH ₄ gas and the flow rate of the CH ₄ gas were changed according to the flow rate change pattern shown in FIG. 5, and the deposition rate of the Si layer was set at 0.15 nm / sec.

Next, as in Example 1, a 70 nm thick ITO (In ₂ O) layer was formed on the second p-type layer as a transparent electrode.
₃ + SnO ₂ ) was vacuum-deposited by a normal vacuum deposition method. Next, as in Example 1, a 5 μm-thick current collecting electrode made of silver (Ag) was vacuum-deposited on the transparent electrode by a normal vacuum deposition method. Next, in the same manner as in Example 1, a 3 μm-thick back electrode made of an Ag—Ti alloy was vacuum-deposited on the back surface of the substrate by a normal vacuum deposition method.

The fabrication of the triple type solar cell using the microwave plasma CVD method has been completed. This solar cell will be referred to as (SC Ex. 14). Table 5 shows the manufacturing conditions of each semiconductor layer. (Comparative Example 14-1) A method similar to that of Example 14 except that the SiH ₄ gas flow rate and the CH ₄ gas flow rate were changed in accordance with the flow rate change pattern in FIG. 6 when forming the second i-type layer in FIG. A triple solar cell was manufactured in the same procedure. This solar cell is referred to as (SC ratio 14-1).

(Comparative Example 14-2) When forming the second i-type layer in FIG. 17, a triple method was performed by the same method and the same procedure as in Example 14 except that the μW power was changed to 0.5 W / cm ^3. A solar cell was fabricated. This solar cell (SC ratio 14-2)
I will call it. (Comparative Example 14-3) When forming the second i-type layer of FIG. 17, a triple type solar cell was manufactured in the same manner and in the same procedure as in Example 14 except that the RF power was changed to 0.15 W / cm ^3. Was prepared. This solar cell will be referred to as (SC Comp. 14-3).

[0221] (Comparative Example 14-4) when forming the second i-type layer in FIG. 17, except that the μW power 0.5 W / cm ^3, the RF power to 0.55 W / cm ³ Example 14 A triple-type solar cell was produced in the same manner and in the same procedure. This solar cell is referred to as (SC ratio 14-4).

(Comparative Example 14-5) When forming the second i-type layer in FIG. 17, the pressure in the deposition chamber 401 was set to 0.08 Torr.
A triple solar cell was manufactured in the same manner and in the same procedure as in Example 14 except for the following. This solar cell is referred to as (SC ratio 14-5). (Comparative Example 14-6) A triple solar cell was manufactured in the same manner and in the same procedure as in Example 14 except that the deposition rate was 3 nm / sec when forming the Si layer in FIG. This solar cell is referred to as (SC ratio 14-6).

(Comparative Example 14-7) A triple solar cell was manufactured in the same manner as in Example 14, except that the thickness of the Si layer in FIG. 17 was changed to 40 nm.
This solar cell is referred to as (SC ratio 14-7).
When the initial photoelectric conversion efficiency and the durability characteristics of these manufactured triple solar cells were measured by the same method as in Example 1, (SC Ex. 14) showed that the conventional triple solar cell (SC
It was found to have better initial photoelectric conversion efficiency and durability than the ratios 14-1) to (SC ratio 14-7).

(Example 15) The solar cell of Example 1 was manufactured using the manufacturing apparatus of FIG. 4 using the microwave plasma CVD method of the present invention, was modularized, and applied to a power generation system. 65 solar cells (SC Ex. 1) of 50 × 50 mm ² were manufactured under the same conditions, the same method, and the same procedure as in Example 1. EVA on 5.0mm thick aluminum plate
An adhesive sheet made of (ethylene vinyl acetate) was placed thereon, a nylon sheet was placed thereon, and the solar cells fabricated thereon were arranged, and serialization and parallelization were performed. An EVA adhesive sheet was placed thereon, and a fluororesin sheet was further placed thereon, and vacuum-laminated to form a module. The initial photoelectric conversion efficiency of the manufactured module was measured in the same manner as in Example 1. Connecting the module to the circuit showing the power generation system of FIG. 18,
An external light that lights up at night was used for the load. The entire system was powered by the battery and the power of the module, and the module was installed at an angle that could best collect sunlight. After one year, the photoelectric conversion efficiency was measured, and the light deterioration rate (photoelectric conversion efficiency after one year / initial photoelectric conversion efficiency) was obtained. This module is called (MJ Actual 15).

(Comparative Example 15-1) A conventional solar cell (SC
Ratio 1-X) (X: 1 to 7) under the same conditions as Comparative Examples 1 to X,
65 pieces were produced by the same method and the same procedure, and were modularized in the same manner as in Example 15. This module (MJ ratio 15-
X). Under the same conditions, the same method, and the same procedure as in Example 15, the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after one year had elapsed were measured, and the light deterioration rate was obtained.

As a result, the light degradation rate of (MJ ratio 15−X) was as follows with respect to (MJ actual 15). Module Light Degradation Ratio ───────────────────────── MJ Actual 15 1.00 MJ Ratio 15-1 0.86 MJ Ratio 15-2 0.67 MJ ratio 15-3 0.86 MJ ratio 15-4 0.70 MJ ratio 15-5 0.82 MJ ratio 15-6 0.70 MJ ratio 15-7 0.83 It was found that the solar cell module had more excellent light degradation characteristics than the conventional solar cell module.

Embodiment 16 Using the manufacturing apparatus of FIG. 4 using the microwave plasma CVD method of the present invention, p / i
The solar cell of FIG. 19 having the second Si layer at the interface was manufactured. In the same manner as in Example 1, a 50 × 50 mm ² n-type polycrystalline silicon substrate manufactured by the casting method is immersed in an aqueous solution of HF and HNO ₃ (diluted to 10% with H ₂ O) for several seconds, and purified water is used. Washed. Next, the substrate was ultrasonically washed with acetone and isopropanol, further washed with pure water, and dried with warm air.

Hydrogen plasma treatment was performed in the same procedure and in the same manner as in Example 1 to form a first p-type layer on the substrate.
Further, a first n-type layer, a first Si layer, an i-type layer, a second
An i layer and a second p-type layer were sequentially formed. When forming the i-type layer, Si is formed according to a flow rate change pattern as shown in FIG.
By changing the H ₄ gas flow rate and the CH ₄ gas flow rate, the first Si
Layer, the deposition rate of the second Si layer is 0.15 nm / sec,
The layer thickness was 10 nm.

Next, on the second p-type layer, as in the first embodiment, as a transparent electrode, ITO (In ₂
O ₃ + SnO ₂ ) was vacuum-deposited by an ordinary vacuum deposition method.
Next, as in Example 1, a 5 μm-thick current collecting electrode made of silver (Ag) was vacuum-deposited on the transparent electrode by a normal vacuum deposition method. Next, similarly to the first embodiment, the Ag-Ti
A 3 μm-thick back electrode made of an alloy was vacuum-deposited by an ordinary vacuum deposition method.

This solar cell is referred to as (SC Ex. 16). Table 6 shows the manufacturing conditions of each semiconductor layer. When the initial photoelectric conversion efficiency and durability characteristics of the manufactured solar cell were measured in the same manner as in Example 1, (SC Ex 16) was the same as (SC Ex 1), and a conventional solar cell (SC ratio 1-1) was obtained. ~ (SC
It was found that it had better initial photoelectric conversion efficiency and durability than the ratio 1-7).

As described above, it has been demonstrated that the effects of the photovoltaic device of the present invention can be exhibited irrespective of the device configuration, device material, and device manufacturing conditions. (Example 17) In this example, a photovoltaic element in which B- and P-atoms were contained in the i-type layer was manufactured. First, to prepare the solar cell of FIG. 1-a using an n-type polycrystalline silicon substrate fabricated by Cass pos- sesses method.

A substrate having a size of 50 × 50 m ² and a thickness of 500 μm was immersed in an aqueous solution of HF and HNO ₃ (diluted to 10% with H ₂ O) for several seconds and washed with pure water. Next, ultrasonic cleaning with acetone and Lee Sopuro <br/> propanol, washed with pure water to further, dried hot air. Next, a source gas supply device 2000 shown in FIG.
And a deposition apparatus 400, a semiconductor layer was formed on the substrate by a manufacturing apparatus using a glow discharge decomposition method. The manufacturing procedure is described below.

In the gas cylinders 2041 to 2047 in the figure, the same source gas as in the first embodiment is sealed. After the preparation for film formation is completed in the same manner as in Example 1, the substrate is subjected to hydrogen plasma treatment, and then the first p
A mold layer, an n-type layer, a Si layer, an i-type layer, and a second p-type layer were formed.

First, to perform the hydrogen plasma treatment, the valve 2003 was gradually opened, H ₂ gas was introduced into the deposition chamber 401, and the mass flow controller 2013 adjusted the H ₂ gas flow rate to 500 sccm. The conductance valve is adjusted while watching the vacuum gauge 402 so that the pressure in the deposition chamber becomes 2.0 Torr, and the heater 405 is set so that the temperature of the substrate 404 becomes 550 ° C. Is closed, a microwave (μW) power supply is set to 0.20 W / cm ³ , a μW power is introduced, a glow discharge is generated, a shutter 415 is opened, and hydrogen plasma treatment of the substrate is performed. Started. After 10 minutes, the shutter was closed, the μW power supply was turned off, the glow discharge was stopped, and the hydrogen plasma treatment was completed. Deposition chamber 401 for 5 minutes
After the H ₂ gas was continuously flowed into the inside, the valve 2003 was closed, and the inside of the deposition chamber 401 and the inside of the gas pipe were evacuated.

Next, to form the first p-type layer, the valve 2003 was gradually opened, H ₂ gas was introduced into the deposition chamber 401, and the mass flow controller was adjusted so that the H ₂ gas flow rate became 50 sccm. Adjusted in 2013. Pressure in the deposition chamber was adjusted with conductance valve while watching the vacuum gauge 402 to be 2.0 Torr, and setting the heater 405 so that the temperature of the substrate 404 is 350 ° C., further where the substrate temperature became stable Valve 200
1, 2005, gradually open, SiH ₄ gas, B ₂ H ₆ /
H ₂ gas was introduced into the deposition chamber 401. At this time, Si
H ₄ gas flow rate is 5 sccm, H ₂ gas flow rate is 100 sccc
m and each of the mass flow controllers were adjusted so that the flow rate of the B ₂ H ₆ / H ₂ gas was 500 sccm. The pressure in the deposition chamber 401 vacuum gauge 4 so as to 2.0Torr
02, the opening of the conductance valve 407 was adjusted. Confirm that the shutter 415 is closed, set the RF power supply to 0.20 W / cm ³ , introduce RF power, cause glow discharge, open the shutter 415, and place the first p-type on the substrate. The formation of the layer was started. Layer thickness 1
Close the shutter was to prepare a first p-type layer of nm, turn off the RF power to stop the glow discharge, a first p
The formation of the mold layer was completed. By closing the valve 2001,2005, SiH ₄ gas into the deposition chamber 401, B ₂ H ₆ / H ₂ gas and stopper influx, after continued to flow compost 5 minutes H ₂ gas into the product chamber 401, the valve close 2003 was evacuated deposition chamber 及 beauty gas pipe 401.

To form the n-type layer, the auxiliary valve 40
8. Open the valve 2003 gradually, introduce H ₂ gas into the deposition chamber 401 through the gas introduction pipe 411, set the mass flow controller 2013 so that the H ₂ gas flow rate becomes 50 sccm, and set the pressure in the deposition chamber to 1 0.0Torr
r with the conductance valve so that the substrate 4
Heater 405 so that the temperature of 04 becomes 350 ° C.
It was set. When the substrate temperature was stabilized, the valves 2001 and 2004 were gradually opened to open SiH ₄ gas and P
H ₃ / H ₂ gas was caused to flow into the deposition chamber 401. At this time,
SiH ₄ gas flow rate ₂ sccm, H ₂ gas flow rate 100 s
Each of the mass flow controllers was adjusted so that the flow rate of ccm and PH ₃ / H ₂ gas became 200 sccm. The opening of the conductance valve 407 was adjusted so that the pressure in the deposition chamber 401 became 1.0 Torr. The power of the RF power source is set to 0.01 W / cm ³ , RF power is introduced to the RF electrode 410, a glow discharge is generated, a shutter is opened, and formation of an n-type layer on the first p-type layer is started. and closes the shutter was to prepare a n-type layer having a thickness of 30 nm, turn off the RF power, stop the glow discharge to complete the formation of the n-type layer. By closing the valve 2001,2004, SiH ₄ gas into the deposition chamber 401, PH ₃ / H ₂ gas flow into the <br/> and stopper of continued flow compost H ₂ gas for 5 minutes into a product chamber 401
After closing the outflow valves 2003, it was evacuated deposition chamber 及 beauty gas pipe 401.

To form the Si layer, the valve 2003 is gradually opened, H ₂ gas is introduced into the deposition chamber 401 through the introduction pipe 411, and the mass flow controller 2013 is set so that the H ₂ gas flow rate becomes 50 sccm. Then, the pressure in the deposition chamber was adjusted with a conductance valve so as to be 1.5 Torr, and the heater 405 was set so that the temperature of the substrate 404 was 270 ° C. When the substrate temperature was stabilized, the valve 2001 was further opened gradually, and SiH ₄ gas was introduced into the deposition chamber 401. At this time, the flow rate of the SiH ₄ gas was ₂ sccm, and the flow rate of the H ₂ gas was 10 sccm.
Each mass flow controller was adjusted to be 0 sccm. The pressure in the deposition chamber 401 is 1.5 Torr
The opening of the conductance valve 407 was adjusted so that Set the power of the RF power supply to 0.01 W / cm ³ ,
RF power was introduced into the RF electrode 410 to generate glow discharge, the shutter was opened, and the formation of a Si layer on the n-type layer was started, and a Si layer having a deposition rate of 0.15 nm / sec and a layer thickness of 10 nm was formed. close the shutter was, turn off the RF power, stop the glow discharge to complete the formation of the Si layer.
When the valve 2001 is closed, the SiH ₄
And stopper the flow rate of the gas, after continued to flow <br/> 5 minutes compost H ₂ gas into the product chamber 401, closing the outflow valves 2003, the deposition chamber 40
It was evacuated 及 beauty gas pipe 1.

Next, to manufacture an i-type layer, the valve 20
03 was gradually opened, H ₂ gas was introduced into the deposition chamber 401, and the mass flow controller 2013 adjusted the H ₂ gas flow rate to 300 sccm. The pressure in the deposition chamber is adjusted by the conductance valve to be 0.01 Torr, and setting the heater 405 so that the temperature is 350 ° C. of the substrate 404, further valves <br/> substrate temperature was stabilized 2001 , 2002, 2004, 200
5 is gradually opened, and SiH ₄ gas, CH ₄ gas, PH ₃ /
H ₂ gas and B ₂ H ₆ / H ₂ gas were flowed into the deposition chamber 401. At this time, SiH ₄ gas flow rate of 100 sccm, CH ₄
300scc gas flow rate is 30sccm, H ₂ gas flow rate
m, PH ₃ / H ₂ gas flow rate was adjusted to ₂ sccm and B ₂ H ₆ / H ₂ gas flow rate was adjusted to 5 sccm by each mass flow controller. The pressure in the deposition chamber 401 is 0.0
The opening of the conductance valve 407 was adjusted to 1 Torr. Next , the power of the RF power supply 403 is set to 0.4
The power was set to 0 W / cm ³ and applied to the RF electrode 403. Thereafter, the power of a not-shown μW power supply is set to 0.20 W / cm ³ , and the power of μW is introduced into the deposition chamber 401 through the dielectric window 413.
Electric power was introduced to generate glow discharge, the shutter was opened, and the formation of an i-type layer on the Si layer was started. Using a computer connected to a mass flow controller,
SiH ₄ gas, CH ₄ according flow change pattern shown in
When the flow rate of the gas was changed and an i-type layer having a thickness of 300 nm was formed, the shutter was closed, the μW power supply was turned off to stop glow discharge, the RF power supply 403 was turned off, and the preparation of the i-type layer was completed. Valves 2001, 2002, 2004, 200
5 to close, SiH ₄ gas into the deposition chamber 401, CH ₄ gas, PH ₃ / H ₂ gas, B ₂ H ₆ / H ₂ and stopper the inflow of gas,
After continuously introduced compost 5 minutes H ₂ gas into the product chamber 401, closing the valve 2003, the deposition chamber and the gas pipe 401 was evacuated.

Next, in order to form a second p-type layer, the valve 2003 was gradually opened, H ₂ gas was introduced into the deposition chamber 401, and the mass flow controller was adjusted so that the H ₂ gas flow rate became 50 sccm. Adjusted in 2013. A pressure in the deposition chamber was adjusted with conductance valve to be 2.0 Torr, and setting the heater 405 so that the temperature of the substrate 404 is 200 ° C., the substrate temperature was stabilized
At this time , the valves 2001, 2002, and 2005 were gradually opened, and SiH ₄ gas, CH ₄ gas, and B ₂ H ₆ / H ₂ gas flowed into the deposition chamber 401. At this time, the flow rate of the SiH ₄ gas is 1 sccm, and the flow rate of the CH ₄ gas is 0.5 scc.
m, H ₂ gas flow rate is _{100sccm, B 2 H 6 / H} 2 gas flow rate were adjusted in each mass flow controllers such that the 100 sccm. The pressure in the deposition chamber 401 is 2.0
The opening of the conductance valve 407 was adjusted to be Torr. The RF power was set to 0.20 W / cm ³ , RF power was introduced, glow discharge was generated, the shutter 415 was opened, and the formation of the second p-type layer on the i-type layer was started. When the second p-type layer having a thickness of 10 nm was formed, the shutter was closed, the RF power was turned off, glow discharge was stopped, and the formation of the second p-type layer was completed. Valves 2001 and 2
002 , 2005 is closed and SiH into the deposition chamber 401 is closed.
₄ gas, CH ₄ gas, B ₂ H ₆ / H ₂ gas and stopper influx, after continued to flow compost <br/> H ₂ gas for 5 minutes into a product chamber 401, closing the valve 2003, the deposition chamber 401 the inner 及 beauty gas pipe were evacuated, closed auxiliary valve 408, the leak valve 409
Was opened, and the deposition chamber 401 was leaked.

Next, a transparent electrode was formed on the second p-type layer.
And a 70 nm thick ITO (In)_TwoO _Two+ SnO_Two)
Vacuum deposition was performed by a normal vacuum deposition method. Next, silver on the transparent electrode
5 μm thick collector electrode made of (Ag) is deposited by ordinary vacuum deposition
Vacuum deposited by the method. Next, on the back surface of the substrate,
The back electrode with a thickness of 3 μm consisting of
Evaporated.

Thus, the production of this solar cell was completed. This solar cell is referred to as (SC Ex. 17). Table 7 shows conditions for forming the first p-type layer, the n-type layer, the Si layer, the i-type layer, and the second p-type layer. (Comparative Example 17-1) The same conditions as in Example 17 except that the SiH ₄ gas flow rate and the CH ₄ gas flow rate were adjusted by the respective mass flow controllers according to the flow rate patterns shown in FIG. 6 when forming the i-type layer. A solar cell was manufactured in the same procedure. This solar cell is referred to as (SC ratio 17-1).

(Comparative Example 17-2) A solar cell was fabricated on a substrate in the same manner and in the same manner as in Example 17, except that no PH ₃ / H ₂ gas was supplied when forming the i-type layer. This solar cell is referred to as (SC ratio 17-2). (Comparative Example 17-3) When forming an i-type layer, B ₂ H ₆ / H
_A solar cell was fabricated on a substrate by the same method and procedure as in Example 17 except that no _two gases were passed. This solar cell (SC
Ratio 17-3).

(Comparative Example 17-4) A solar cell was manufactured under the same conditions and in the same procedure as in Example 17, except that the μW power was changed to 0.5 W / cm ³ when forming the i-type layer. This solar cell is referred to as (SC ratio 17-4). (Comparative Example 17-5) A solar cell was fabricated under the same conditions and in the same procedure as in Example 17 except that the RF power was changed to 0.15 W / cm ³ when forming the i-type layer. This solar cell is referred to as (SC ratio 17-5).

(Comparative Example 17-6) When forming an i-type layer, μW power was 0.5 W / cm ³ and RF power was 0.55.
A solar cell was manufactured under the same conditions and in the same procedure as in Example 17 except that the value was changed to W / cm ³ . This solar cell (SC ratio 1
7-6). (Comparative Example 17-7) A solar cell was manufactured under the same conditions and in the same procedure as in Example 17 except that the pressure in the deposition chamber was set to 0.08 Torr when forming the i-type layer. This solar cell is referred to as (SC ratio 17-7).

(Comparative Example 17-8) Example 1 was repeated except that the deposition rate was 3 nm / sec when forming the Si layer.
A solar cell was manufactured under the same conditions and in the same procedure as in 7. This solar cell will be referred to as (SC ratio 17-8). (Comparative Example 17-9) When forming the Si layer, the layer thickness was set to 40.
A solar cell was manufactured under the same conditions and in the same procedure as in Example 17, except for changing the thickness to nm. This solar cell (SC ratio 17-
9).

The measurement of the initial light conversion efficiency (photovoltaic power / incident light power) and durability characteristics of the manufactured solar cells (SC Ex. 17) and (SC Comp. 17-1) to (SC Comp. 17-9) were carried out in Examples. Performed in the same manner as 1. As a result of the measurement, (SC actual 1
For the solar cell of 7), (SC ratio 17-1) to (SC
The initial photoelectric conversion efficiency at the ratio of 17-9) was as follows.

(SC ratio 17-1) 0.82 times (SC ratio 17-2) 0.81 times (SC ratio 17-3) 0.80 times (SC ratio 17-4) 0.65 times (SC ratio) 17-5) 0.81 times (SC ratio 17-6) 0.63 times (SC ratio 17-7) 0.68 times (SC ratio 17-8) 0.70 times (SC ratio 17-9) 83 times The durability characteristics were measured in the same manner as in Example 1. As a result of the measurement, the (SC ratio 17)
The durability characteristics of (-1) to (SC ratio 17-9) were as follows.

(SC ratio 17-1) 0.82 times (SC ratio 17-2) 0.80 times (SC ratio 17-3) 0.80 times (SC ratio 17-4) 0.67 times (SC ratio) 17-5) 0.83 times (SC ratio 17-6) 0.65 times (SC ratio 17-7) 0.76 times (SC ratio 17-8) 0.73 times (SC ratio 17-9) Next, the relationship between the band gap of the i-type layer and the C / Si composition was examined in the same manner as in Example 1. The result was the same as that in FIG.

The fabricated solar cell (SC Ex. 17)
The composition analysis in the thickness direction of Si atoms and C atoms in the i-type layer of (SC ratio 17-1) to (SC ratio 17-9) is performed in the same manner as in the composition analysis described above, and the Si atom and carbon atom are analyzed. When the band gap in the layer thickness direction of the i-type layer was determined from the composition ratio, the same tendency as in FIG. 8 was obtained, and the solar cells of (SC Ex. 17), (SC Comp. 17-2) to (SC Comp. 17-9) In this case, the position of the minimum value of the band gap is p
/ I is deviated in the interface direction, and in the solar cell of (SC ratio 17-1), the position of the minimum value of the band gap is deviated in the Si / i interface direction from the center position of the i-type layer. .

As described above, (SC actual 17), (SC ratio 17−
The changes in the band gap in the layer thickness direction of 1) to (SC ratio 17-9) are caused by the source gas containing Si (in this case, SiH ₄ gas) and the source gas containing C (in this case, flowing into the deposition chamber). In this case, it was confirmed that it depends on the flow ratio of CH ₄ gas). Next, (SC actual 17), (SC ratio 17−
1) to (SC ratio 17-9) P atom and B in i-type layer
The composition analysis of atoms in the layer thickness direction was performed using a secondary ion mass spectrometer (IMS-3F manufactured by CAMECA). As a result of the measurement, P atoms and B atoms were uniformly distributed in the layer thickness direction, and the composition ratio was as follows.

P / (Si + C) B / (Si + C) (SC Ex. 17) ３3 ppm to 10 ppm (SC ratio 17-1) ３3 ppm to 10 ppm (SC ratio 17-2) D. -10 ppm (SC ratio 17-3) -3 ppm D. (SC ratio 17-4) ４4 ppm to 18 ppm (SC ratio 17-5) ３3 ppm to 10 ppm (SC ratio 17-6) ４4 ppm to 15 ppm (SC ratio 17-7) ３3 ppm to 10 ppm (SC ratio 17-8) ) -3 ppm -10 ppm (SC ratio 17-9) -3 ppm -10 ppm D. Below the detection limit (Comparative Example 17-10) μ introduced when forming an i-type layer
W power and RF power are variously changed, and other conditions are examples.
In the same manner as in 17, some solar cells were produced. μW electricity
The force and the deposition rate have the same relationship as in FIG.
ΜW power is 0.32 W / cm, independent of F power^Threethat's all
In this case, the electric power is constant_FourWith gas
CH_FourIt was found that the gas was 100% decomposed.
AM1.5 (100 mW / cm ^Two) When light is irradiated
When the initial photoelectric conversion efficiency of the solar cell was measured, FIG.
The result showed the same tendency as. That is, the μW power is S
iH_FourGas and CH_FourΜW electricity to decompose 100% of gas
Force (0.32W / cm^Three) And RF power is μW
Greater initial photoelectric conversion efficiency when power is higher
I understood that.

(Comparative Example 17-11) When forming the i-type layer in Example 17, the flow rate of the gas introduced into the deposition chamber 401 was set to S.
Some solar cells were fabricated by changing the iH ₄ gas to 50 sccm and the CH ₄ gas to 10 sccm, not introducing the H ₂ gas, and varying the μW power and the RF power. Other conditions were the same as in Example 17. When the relationship between the deposition rate, the μW power, and the RF power was examined, the deposition rate did not depend on the RF power and the μW power was 0.18 W / c as in Comparative Example 17-10.
It was found that the SiH ₄ gas and the CH ₄ gas, which are the source gases, were decomposed 100% with this μW power at a constant value of m ³ or more. When the initial photoelectric conversion efficiency of the solar cell when irradiating AM1.5 light was measured, the result showed the same tendency as FIG. That is, the μW power is S
μW for decomposing 100% of iH ₄ gas and CH ₄ gas
Power (0.18 W / cm ³ ) or less and RF power is μ
It was found that the initial photoelectric conversion efficiency was significantly improved when the power was larger than the W power.

(Comparative Example 17-12) When forming the i-type layer in Example 17, the flow rate of the gas introduced into the deposition chamber 401 was set to S.
iH ₄ gas 200 sccm, CH ₄ gas 50 sccm,
H ₂ gas was changed to 500 sccm and the substrate temperature was 3
Change the heater setting so that the temperature becomes
Several solar cells were fabricated with various power and RF powers. Other conditions were the same as in Example 17.

When the relationship between the deposition rate and the μW power and RF power was examined, the deposition rate was R
The μW power was constant at 0.65 W / cm ³ or more without depending on the F power, and it was found that the SiH ₄ gas and CH ₄ gas as the raw material gas were decomposed by 100% with this power. When the initial photoelectric conversion efficiency of the solar cell when irradiating AM1.5 light was measured, the result showed the same tendency as FIG. In other words, the μW power changes the SiH ₄ gas to 1
It was found that the initial photoelectric conversion efficiency was greatly improved when the power was not more than the μW power (0.65 W / cm ³ ) at which the power was decomposed by 00% and the RF power was larger than the μW power.

(Comparative Examples 17-13) In forming the i-type layer in Example 17, the pressure in the deposition chamber was increased from 3 mTorr to 20 m / s.
Various conditions were changed up to 0 mTorr, and other conditions were the same as in Example 17.
Some solar cells were produced in the same manner as described above. AM1.5
When the initial photoelectric conversion efficiency of the solar cell when irradiating light was measured, the result was as shown in FIG.
It was found that the initial photoelectric conversion efficiency was greatly reduced at Torr or higher.

(Comparative Examples 17-14) In forming the Si layer in Example 17, the deposition rate was changed variously by changing the flow rate of the SiH ₄ gas and the RF power, and the other conditions were the same as in Example 17. Some solar cells were produced. AM
When the initial photoelectric conversion efficiency of the solar cell when irradiating 1.5 light was measured, the deposition rate of the Si layer was 2 nm / sec.
From the above, it was found that the initial photoelectric conversion efficiency was greatly reduced.

(Comparative Examples 17 to 15) When forming the Si layer in Example 17, several solar cells were produced by changing the layer thickness variously and using the other conditions as in Example 17. AM1.
Measurement of the initial photoelectric conversion efficiency of the solar cell when five light beams were irradiated showed that the initial photoelectric conversion efficiency was greatly reduced when the layer thickness was 30 nm or more.

As described above, (Comparative Example 17-1) to (Comparative Example 17)
-15), the solar cell of the present invention (SC Ex. 1)
7) was demonstrated to have more excellent characteristics than conventional solar cells (SC ratio 17-1) to (SC ratio 17-9). (Embodiment 18) The band gap (E
g) producing several solar cells by changing the position of the minimum value in the layer thickness direction, the size of the minimum value, and the pattern,
The initial photoelectric conversion efficiency and durability characteristics were examined in the same manner as in Example 17. At this time, a solar cell having a band gap shown in FIG. 12 was produced in the same manner as in Example 17, except for the change pattern of the SiH ₄ gas flow rate and the CH ₄ gas flow rate of the i-type layer.

Table 8 shows the results obtained by examining the initial photoelectric conversion efficiency and durability characteristics of these manufactured solar cells (the values in the table are based on SC Example (18-1)). As can be seen from these results, the band gap of the i-type layer smoothly changes in the layer thickness direction regardless of the size and the change pattern of the minimum value of the band gap, and the position of the minimum value of the band gap is changed to the i-type layer. It has been found that the solar cell of the present invention, which is deviated in the p / i interface direction from the center position of the above, is superior.

(Example 19) A solar cell was produced in the same manner as in Example 17 except that the concentration and type of the valence electron controlling agent in the i-type layer were changed, and the initial photoelectric conversion characteristics and durability were the same as in Example 1. I checked in. At this time, it was the same as Example 17 except that the concentration and type of the valence electron controlling agent in the i-type layer were changed.

(Example 19-1) The flow rate of the gas (B ₂ H ₆ / H ₂ gas) of the valence electron controlling agent serving as the acceptor of the i-type layer was reduced to 1/5, and the total H ₂ flow rate was changed to that of Example 17. When a solar cell (SC Ex 19-1) having the same structure as that described above was manufactured,
Like (SC Ex. 17), (SC Ex. 19-1) has better initial photoelectric conversion efficiency and durability than conventional solar cells (SC Comp. 17-1) to (SC Comp. 17-9). I understood.

(Example 19-2) The flow rate of the gas (B ₂ H ₆ / H ₂ gas) of the valence electron controlling agent serving as the acceptor of the i-type layer was increased by 5 times, and the total H ₂ flow rate was the same as in Example 17. When a solar cell (SC Ex. 19-2) was manufactured, (S
Similar to (SC Ex. 17), C Ex. 19-2) may have better initial photoelectric conversion efficiency and durability than conventional solar cells (SC Comp. 17-1) to (SC Comp. 17-9). Do you get it.

(Example 19-3) The flow rate of the gas (PH ₃ / H ₂ gas) of the valence electron controlling agent serving as the donor of the i-type layer was reduced to 1/5, and the total H ₂ flow rate was the same as in Example 17. (SC Ex. 19-3) was manufactured, and as in (SC Ex. 17), the conventional solar cells (SC Comp. 17-1) to (SC Comp. ) Was found to have even better initial photoelectric conversion efficiency and durability characteristics.

(Example 19-4) The flow rate of the gas (PH ₃ / H ₂ gas) of the valence electron controlling agent serving as the donor of the i-type layer was made five times, and the total H ₂ flow rate was made the same as in Example 17. When a solar cell (SC Ex. 19-3) was manufactured, (SC Ex. 1)
9-4) is a conventional solar cell (S
It was found that they had better initial photoelectric conversion efficiency and durability than C ratio 17-1) to (SC ratio 17-9).

(Example 19-5) Instead of B ₂ H ₆ / H ₂ gas, trimethyl aluminum (Al (CH ₃ ) ₃ , TM) was used as a valence electron controlling agent gas serving as an acceptor for the i-type layer.
A). At this time, TMA (purity: 99.99%) sealed in a liquid cylinder was gasified by bubbling with hydrogen gas and introduced into the deposition chamber 401 in the same manner and procedure as in Example 17, except that the solar cell (SC 19-5). At this time, TMA / H ₂
The gas flow rate was 10 sccm. The fabricated solar cell (SC Ex. 19-5) has better initial photoelectric conversion efficiency and durability than the conventional solar cells (SC Comp. 17-1) to (SC Comp. 17-9), similarly to (SC Ex. 17). It has been found to have properties.

(Example 19-6) A solar cell using hydrogen sulfide (H ₂ S) instead of PH ₃ / H ₂ gas as a valence electron controlling agent gas serving as a donor of the i-type layer was manufactured. NH ₃ / H ₂ gas cylinder with H ₂ S gas diluted to 100ppm with hydrogen (99.999% pure Example 17, the following "H ₂ S /
[H ₂ ]] was replaced with a cylinder, and a solar cell (SC Ex. 19-6) was produced in the same manner and procedure as in Example 17.

At this time, the flow rate of the H ₂ S / H ₂ gas is 1 scc.
m. The fabricated solar cell (SC Ex. 19-6) is (S
Similar to C Ex 17), a conventional solar cell (SC ratio 17-1)
It was found to have better initial photoelectric conversion efficiency and endurance characteristics than (SC ratio 17-9). (Example 20) A solar cell shown in FIG. 1-b was fabricated using a p-type polycrystalline silicon substrate. Performing a plasma treatment on the substrate, followed by a first n-type layer, a p-type layer, an i-type layer,
An i-layer and a second n-type layer were sequentially formed. Table 9 shows the forming conditions. When forming the i-type layer, the SiH ₄ gas flow rate and CH ₄
The gas flow rate was changed as shown in the pattern of FIG. 6 so that the minimum value of the band gap came from the i / p interface.
The layer deposition rate was 0.15 nm / sec. The layers other than the substrate and the semiconductor layer were manufactured using the same conditions and the same method as in Example 17.

The manufactured solar cell (SC Ex. 20) is (SC
As in the case of the actual solar cell 17), the conventional solar cell (SC ratio 17-1) ~
It was found to have better initial photoelectric conversion efficiency and durability than (SC ratio 17-9). (Example 21) A solar cell having the maximum value of the band gap of the i-type layer near the p / i interface and having a thickness of 20 nm in the region was obtained by using the flow rate change pattern of the i-type layer shown in FIG. It produced using it.

An i-type layer was manufactured using the same conditions and the same method as in Example 17 except that the flow rate change pattern was changed. Next, the composition analysis of the solar cell was performed in the same manner as in Example 17, and the change in the band gap in the layer thickness direction of the i-type layer was examined based on FIG. It became. The manufactured vertical (SC Ex. 21) is the same as (SC Ex. 17) in the conventional solar cells (SC ratio 17-1) to (SC ratio 17).
It was found that it had better initial photoelectric conversion efficiency and durability than -9).

(Comparative Example 21) There was a region having a maximum band gap near the p / i interface of the i-type layer, and several solar cells were manufactured with various thicknesses of the region. Except for the thickness of the region, it was manufactured using the same conditions and the same method as in Example 21. When the initial photoelectric conversion efficiency and durability of the manufactured solar cell were measured, the thickness of the region was 1 nm.
Above 30 nm or less, the solar cell (SC
Further better initial photoelectric conversion efficiency and durability than 17) were obtained.

(Example 22) The band gap of the i-type layer has a maximum value near the i / Si interface, and the thickness of the region is 1
A solar cell having a thickness of 5 nm was manufactured using the flow rate change pattern of the i-type layer shown in FIG. Except for changing the flow rate change pattern of the i-type layer, it was manufactured using the same conditions and the same method as in Example 17. Next, the composition of the solar cell was analyzed in Example 17.
When the change in the band gap in the thickness direction of the i-type layer was examined based on FIG. 7, the result was as shown in FIG. 13D. The manufactured solar cell (SC Ex. 22) is similar to the conventional solar cell (SC Ex.
It was found to have better initial photoelectric conversion efficiency and durability than 1) to (SC ratio 17-9).

(Comparative Example 22) There was a region having the maximum band gap near the i / Si interface of the i-type layer, and several solar cells were manufactured with various thicknesses of the region. Except for the thickness of the region, it was manufactured using the same conditions and the same method as in Example 22. When the initial photoelectric conversion efficiency and durability of the manufactured solar cell were measured, the thickness of the region was 1 nm.
As described above, when the thickness is 30 nm or less, even better initial photoelectric conversion efficiency and durability than the solar cell of Example 17 (SC Ex. 17) were obtained.

Example 23 A solar cell in which a valence electron controlling agent was distributed in an i-type layer was manufactured. Fig. 20-a shows PH ₃
4 shows the change patterns of the flow rates of the / H ₂ gas and the B ₂ H ₆ / H ₂ gas. At the time of fabrication, the same conditions, the same method, and procedure as those of Example 17 were used except that the flow rates of PH ₃ / H ₂ gas and B ₂ H ₆ / H ₂ gas were changed.

The fabricated solar cell (SC Ex. 23) is (SC
As in the case of the actual solar cell 17), the conventional solar cell (SC ratio 17-1) ~
It was found to have better initial photoelectric conversion efficiency and durability than (SC ratio 17-9). Further, when the change in the layer thickness direction of the P atoms and the B atoms contained in the i-type layer was examined by using a secondary ion mass spectrometer (SIMS), as shown in FIG. It was found that the content of P and B atoms was the minimum at the position.

(Example 24) A solar cell having an i-type layer containing oxygen atoms was manufactured. In forming the i-type layer, O ₂ / He gas is supplied at 10 sc in addition to the gas flowing in Example 17.
The same conditions, the same method, and the same procedure as in Example 17 were used, except that the sample was introduced into the deposition chamber 401. The manufactured solar cell (SC Ex. 24) has better initial photoelectric conversion efficiency and durability characteristics than the conventional solar cells (SC Comp. 17-1) to (SC Comp. 17-9), similarly to (SC Ex. 17). It was found to have.

Also, the content of oxygen atoms in the i-type layer is determined by SI
As a result of examination by MS, it was contained almost uniformly, and 2 × 10 ¹⁹
(Pieces / cm ² ). (Example 25) A silicon solar cell having an i-type layer containing nitrogen atoms was produced. When forming the i-type layer, NH ₃ / H ₂ gas is supplied at 5 scc in addition to the gas flowing in Example 17.
m, the same conditions, the same method, and the same procedure as in Example 17 were used, except that they were introduced into the deposition chamber 401. The manufactured solar cell (SC Ex. 25) has better initial photoelectric conversion efficiency and durability than the conventional solar cells (SC Comp. 17-1) to (SC Comp. 17-9), similarly to (SC Ex. 17). It was found to have. Further, the content of nitrogen atoms in the i-type layer is determined by SI
As a result of examination by MS, it was contained almost uniformly, and 3 × 10 ¹⁷
(Pieces / cm ² ).

(Example 26) An oxygen atom and a nitrogen atom were added to an i-type layer.
A solar cell containing elemental atoms was produced. i-type layer
When forming, in addition to the gas flowing in Example 17, O_Two/ He
5 sccm gas, NH_Two/ H_Two5 sccm of gas
The same conditions as in Example 17 except that it is introduced into the storage chamber 401,
The same method and the same procedure were used. The fabricated solar cell (SC
Example 26) is similar to (SC example 17) in that the conventional solar cell (S
Even better than C ratio 17-1) to (SC ratio 17-9)
Have high initial photoelectric conversion efficiency and durability
Was. Also, the content of oxygen atoms and nitrogen atoms in the i-type layer
When examined by SIMS, it was found to be almost uniformly contained.
1 × 10¹⁹(Pcs / cm^Two), 3 × 10¹⁷(Pcs / cm
^Two).

(Example 27) A solar cell was manufactured in which the hydrogen content of the i-type layer was changed corresponding to the silicon content. The O ₂ / He gas cylinder was filled with SiF ₄ gas (purity 99.
When the i-type layer is formed by replacing the cylinder with a cylinder, FIG.
According to the flow pattern of 5-a, SiH ₄ gas, CH ₄
The flow rates of the gas and the SiF ₄ gas were changed. The change in band gap in the layer thickness direction of this solar cell (SC Ex. 27) was determined by the same method as in Example 17. FIG.
The result was similar to.

Further, the content of hydrogen atoms and silicon atoms was analyzed in the thickness direction using a secondary ion mass spectrometer. The results showed the same tendency as in FIG. 15-c, and it was found that the hydrogen atom content had a distribution in the layer thickness direction corresponding to the silicon atom content. This solar cell (SC
When the initial photoelectric conversion efficiency and the durability characteristics of Example 27) were obtained, the conventional solar cell (S
It was found that they had better initial photoelectric conversion efficiency and durability than C ratio 17-1) to (SC ratio 17-9).

Example 28 When forming the semiconductor layer of the solar cell of FIG. 1 by the manufacturing apparatus using the microwave plasma CVD method shown in FIG. 4, a silicon atom-containing gas (Si
Example 17 except that H ₄ gas) and a carbon atom-containing gas (CH ₄ gas) were mixed at a distance of 1 m from the deposition chamber.
A solar cell (SC Ex. 28) was produced in the same manner and in the same procedure as described above. The fabricated solar cell (SC actual 28) is (SC actual 1)
It was found to have better initial photoelectric conversion efficiency and durability than 7).

(Example 29) When forming a first p-type layer by gas diffusion and forming an i-type layer, C ₂ H ₂ gas was used instead of CH ₄ gas, and a positive DC A solar cell was manufactured by applying a bias and changing RF power, DC bias, and μW power. First, BBr ₃ (BBr ₃ / H ₂ gas) obtained by diluting an O ₂ / He gas cylinder to 10% with hydrogen.
The cylinder was replaced with a cylinder, and the CH ₄ gas cylinder was further replaced with a C ₂ H ₂ gas.

When forming the first p-type layer, a substrate temperature of 90
0 ° C., BBr ₃ / H ₂ gas flow rate 500 sccm, internal pressure 30
Under the condition of Torr, B was diffused into the n-type substrate. Upon reaching the junction depth 300 nm, stop the introduction of BBr ₃ / H ₂ gas. H ₂ gas was kept flowing for 5 minutes. Further, when forming the i-type layer, by introducing a C ₂ H ₂ gas instead of CH ₄ gas was varied according to the flow pattern as shown in FIG. 14-a. Further, as shown in FIG. 16, the RF power, the DC bias, and the μW power were changed. Except for the first p-type layer and the i-type layer, the same conditions, the same method, and the same procedure as in Example 17 were used. The produced solar cell (SC 29), (SC real 1
7), conventional solar cells (SC ratio 17-1) to (S
It was found to have better initial photoelectric conversion efficiency and durability than C ratio 17-9).

(Embodiment 30) Using the manufacturing apparatus of FIG. 4 using the microwave plasma CVD method of the present invention, FIG.
Was manufactured. The substrate was manufactured in Example 17
An n-type polycrystalline silicon substrate manufactured by the casting method was used in the same manner as in the above.

One side of a 50 × 50 mm ² substrate was heated at a temperature of 10
It was immersed in a 1% NaOH aqueous solution at 0 ° C. for 5 minutes, and washed with pure water. Scan the surface immersed in NaOH with a scanning electron microscope (SE
Observed in (M), irregularities having a pyramid structure were formed on the surface, and the substrate was textured (Te
xtured). Next, the substrate was ultrasonically washed with acetone and isopropanol, further washed with pure water, and dried with warm air.

Water was prepared in the same manner and in the same manner as in Example 17.
Elementary plasma treatment and the first surface on the textured surface of the substrate
And a first n-type layer, a first i-type layer
Layer, second p-type layer, second n-type layer, Si layer, second i-type
A layer and a third p-type layer were sequentially formed. Form a second i-type layer
At the time, the SiH
_FourGas flow, CH_FourChange the gas flow rate to deposit the Si layer
The speed was 0.15 nm / sec.

Next, as in Example 17, a 70-nm-thick ITO (In ₂ O) layer was formed on the third p-type layer as a transparent electrode.
₃ + SnO ₂ ) was vacuum-deposited by a normal vacuum deposition method. Next, a 5 μm-thick current collecting electrode made of silver (Ag) was vacuum-deposited on the transparent electrode in the same manner as in Example 17 by a normal vacuum deposition method. Next, the Ag-T
A 3 μm-thick back electrode made of an i-alloy was vacuum-deposited by a normal vacuum deposition method.

Thus, the fabrication of the triple solar cell using the microwave plasma CVD method is completed. This solar cell is referred to as (SC Ex 30), and Table 10 shows the manufacturing conditions of each semiconductor layer. (Comparative Example 30-1) A method similar to that of Example 30 except that the flow rate of the SiH ₄ gas and the flow rate of the CH ₄ gas were changed in accordance with the flow rate change pattern of FIG. 6 when forming the second i-type layer of FIG. A triple solar cell was manufactured in the same procedure. This solar cell will be referred to as (SC ratio 30-1).

(Comparative Example 30-2) When forming the second i-type layer of FIG. 17, except that no PH ₃ / H ₂ gas was allowed to flow, a solar cell was formed on the substrate by the same method and procedure as in Example 30. A battery was manufactured. This solar cell is referred to as (SC ratio 30-2). In forming the second i-type layer (Comparative Example 30-3) 17, the same manner as in Example 30 except that no shed B ₂ H ₆ / H ₂ gas, solar cell on a substrate in step Was prepared. This solar cell is referred to as (SC ratio 30-3).

(Comparative Example 30-4) When forming the second i-type layer in FIG. 17, a triple method was performed in the same manner and in the same procedure as in Example 30 except that the μW power was changed to 0.5 W / cm ^3. A solar cell was fabricated. This solar cell (SC ratio 30-4)
I will call it. (Comparative Example 30-5) When forming the second i-type layer in FIG. 17, a triple type solar cell was manufactured in the same manner and in the same procedure as in Example 30 except that the RF power was changed to 0.15 W / cm ^3. Was prepared. This solar cell is referred to as (SC ratio 30-5).

[0290] (Comparative Example 30-6) when forming the second i-type layer in FIG. 17, except that the μW power 0.5 W / cm ^3, the RF power to 0.55 W / cm ³ Example 30 A triple-type solar cell was produced in the same manner and in the same procedure. This solar cell will be referred to as (SC ratio 30-6).

(Comparative Example 30-7) When forming the second i-type layer in FIG. 17, the pressure in the deposition chamber 401 was set to 0.08 Torr.
A triple-type solar cell was produced in the same manner and in the same procedure as in Example 30 except for the following. This solar cell is referred to as (SC ratio 30-7). (Comparative Example 30-8) A triple type solar cell was fabricated in the same manner as in Example 30, except that the deposition rate was 3 nm / sec when forming the Si layer in FIG. This solar cell will be referred to as (SC ratio 30-8).

(Comparative Example 30-9) A triple solar cell was manufactured in the same manner as in Example 30, except that the thickness of the Si layer in FIG. 17 was changed to 40 nm.
This solar cell is referred to as (SC ratio 30-9).
When the initial photoelectric conversion efficiency and the durability characteristics of these manufactured triple solar cells were measured by the same method as in Example 17, (SC Ex 30) showed that the conventional triple solar cell (SC
It was found to have better initial photoelectric conversion efficiency and durability than the ratios 30-1) to (SC ratio 30-9).

(Example 31) The solar cell of Example 17 was manufactured using the manufacturing apparatus of FIG. 4 using the microwave plasma CVD method of the present invention, was modularized, and was applied to a power generation system. A 50 × 50 mm ² solar cell (SC Ex. 17) was prepared under the same conditions, the same method, and the same procedure as in Example 17.
Five were produced. E on a 5.0 mm thick aluminum plate
An adhesive sheet made of VA (ethylene vinyl acetate) was placed thereon, a nylon sheet was placed thereon, and the solar cells produced were further arranged thereon to perform serialization and parallelization. An EVA adhesive sheet was placed thereon, and a fluororesin sheet was further placed thereon, and vacuum-laminated to form a module. The initial photoelectric conversion efficiency of the manufactured module was measured in the same manner as in Example 17.
The module was connected to the circuit showing the power generation system of FIG. 18, and an external light that was lit at night was used for the load. The entire system was powered by the battery and the power of the module, and the module was installed at an angle that could best collect sunlight. 1
The photoelectric conversion efficiency after a lapse of one year was measured, and the light deterioration rate (photoelectric conversion efficiency after one year / initial photoelectric conversion efficiency) was obtained. This module will be called (MJ Actual 31).

(Comparative Example 31-1) A conventional solar cell (SC
Sixty-five ratios 17-X) (X: 1 to 9) were produced under the same conditions, the same method, and the same procedure as those of Comparative Example 17-X, and were modularized as in Example 31. This module (MJ ratio 3
1-X). The initial photoelectric conversion efficiency and the photoelectric conversion efficiency after one year had elapsed were measured under the same conditions, the same method, and the same procedure as in Example 31, and the light deterioration rate was obtained.

As a result, the light degradation rate of (MJ ratio 31-X) was as follows with respect to (MJ actual 31). Module Light Degradation Ratio ───────────────────────── MJ Actual 31 1.00 MJ Ratio 31-1 0.80 MJ Ratio 31-2 0.80 MJ ratio 31-3 0.78 MJ ratio 31-4 0.76 MJ ratio 31-5 0.80 MJ ratio 31-6 0.72 MJ ratio 31-7 0.68 MJ ratio 31-8 0.0. From the results of 70 MJ ratio 31-9 0.82 and above, it was found that the solar cell module of the present invention had more excellent light degradation characteristics than the conventional solar cell module.

(Example 32) Microwave plasma of the present invention
Using the manufacturing apparatus shown in FIG.
The solar cell of FIG. 19 having the second Si layer at the interface was fabricated.
Was. Manufactured by the casting method as in Example 17.
Built 50 × 50mm ^TwoN-type polycrystalline silicon substrate
HF and HNO_Three(H_TwoAqueous solution (diluted to 10% with O)
For several seconds and washed with pure water. Then acetone and isop
Ultrasonic cleaning with lopanol, further cleaning with pure water, warm air
Let dry.

Hydrogen plasma treatment is performed in the same procedure and in the same manner as in Example 17, to form a first p-type layer on the substrate, and further to form an n-type layer, a first Si layer, an i-type layer, 2 Si
A layer and a second p-type layer were sequentially formed. When forming the i-type layer, the flow rate of the SiH ₄ gas and the flow rate of the CH ₄ gas are changed according to the flow rate change pattern shown in FIG. 5, and the deposition rate of the first Si layer and the second Si layer is 0.15 nm / sec. And the layer thickness was 10 nm.

Next, on the second p-type layer, a 70 nm-thick ITO (In
₂ O ₃ + SnO ₂ ) was vacuum deposited by a normal vacuum deposition method. Next, as in Example 17, silver (Ag) was formed on the transparent electrode.
A 5 μm-thick current collecting electrode made of was vacuum-deposited by an ordinary vacuum deposition method. Next, similarly to the seventeenth embodiment, A
A back electrode made of a g-Ti alloy and having a thickness of 3 μm was vacuum-deposited by a normal vacuum deposition method.

This solar cell is referred to as (SC Ex 32). Table 11 shows the conditions for forming each semiconductor layer. When the initial photoelectric conversion efficiency and the durability characteristics of the manufactured solar cell were measured by the same method as in Example 17, (SC Ex. 32) was (SC Ex. 32).
As in the case of the actual solar cell 17), the conventional solar cell (SC ratio 17-1) ~
It was found to have better initial photoelectric conversion efficiency and durability than (SC ratio 17-9).

[0300] (Example 33) using a n-type polycrystalline silicon substrate fabricated by Cass pos- sesses method to produce the solar cell and the second p-type layer and a laminate structure in the configuration shown in FIG. 1-a . 50 × 50m ² ,
A substrate having a thickness of 500 μm is HF and HNO ₃ (10% with H ₂ O).
(Diluted in water) for several seconds and washed with pure water. Next, ultrasonic cleaning with acetone and Lee isopropanol, further
Pure water washed and dried warm air in.

Next, the source gas supply device 200 shown in FIG.
A semiconductor layer was formed on a substrate by a manufacturing apparatus using a glow discharge decomposition method including a deposition apparatus 400 and a deposition apparatus 400. Hereinafter, the manufacturing procedure will be described. In the gas cylinders 2041 to 2047 in the figure, the same source gas as in the first embodiment is sealed.

After the preparation for film formation was completed in the same manner as in Example 1, the substrate was subjected to hydrogen plasma treatment,
4, a first p-type layer, an n-type layer, a Si layer, an i-type layer, a second
Was formed. First, to perform the hydrogen plasma treatment, the valve 2003 was gradually opened, H ₂ gas was introduced into the deposition chamber 401, and the mass flow controller 2013 adjusted the H ₂ gas flow rate to 500 sccm. The conductance valve is adjusted while watching the vacuum gauge 402 so that the pressure in the deposition chamber becomes 2.0 Torr, and the heater 4 is adjusted so that the temperature of the substrate 404 becomes 550 ° C.
05, and confirm that the shutter 415 is closed when the substrate temperature is stabilized.
W) The power supply was set to 0.20 W / cm ³ , a μW power was introduced, glow discharge was generated, the shutter 415 was opened, and the hydrogen plasma treatment of the substrate was started. After 10 minutes, the shutter was closed, the μW power supply was turned off, the glow discharge was stopped, and the hydrogen plasma treatment was completed. After continuously flowing H ₂ gas into the deposition chamber 401 for 5 minutes, the valve 20
03 was closed, and the inside of the deposition chamber 401 and the inside of the gas pipe were evacuated.

Next, to form the first p-type layer, the valve 2003 was gradually opened, H ₂ gas was introduced into the deposition chamber 401, and the mass flow controller was adjusted so that the H ₂ gas flow rate became 50 sccm. Adjusted in 2013. Pressure in the deposition chamber was adjusted with conductance valve while watching the vacuum gauge 402 to be 2.0 Torr, and setting the heater 405 so that the temperature of the substrate 404 is 350 ° C., further where the substrate temperature became stable Valve 200
1, 2005, gradually open, SiH ₄ gas, B ₂ H ₆ /
H ₂ gas was introduced into the deposition chamber 401. At this time, Si
H ₄ gas flow rate is 5 sccm, H ₂ gas flow rate is 100 sccc
m and each of the mass flow controllers were adjusted so that the flow rate of the B ₂ H ₆ / H ₂ gas was 500 sccm. Vacuum gauge 4 so that the pressure in deposition chamber 401 becomes 2.0 Torr.
02, the opening of the conductance valve 407 was adjusted. Confirm that the shutter 415 is closed, set the RF power supply to 0.20 W / cm ³ , introduce RF power, cause glow discharge, open the shutter 415, and place the first p-type on the substrate. The formation of the layer was started. Layer thickness 1
Close the shutter was to prepare a first p-type layer of nm, turn off the RF power to stop the glow discharge, a first p
The formation of the mold layer was completed. By closing the valve 2001,2005, SiH ₄ gas into the deposition chamber 401, B ₂ H ₆ / H ₂ gas and stopper influx, after continued to flow compost 5 minutes H ₂ gas into the product chamber 401, the valve close 2003 was evacuated deposition chamber 及 beauty gas pipe 401.

To form the n-type layer, the auxiliary valve 40
8. Open the valve 2003 gradually, introduce H ₂ gas into the deposition chamber 401 through the gas introduction pipe 411, set the mass flow controller 2013 so that the H ₂ gas flow rate becomes 50 sccm, and set the pressure in the deposition chamber to 1 0.0Torr
r with the conductance valve so that the substrate 4
Heater 405 so that the temperature of 04 becomes 350 ° C.
It was set. When the substrate temperature became stable, the valves 2001 and 2004 were gradually opened, and SiH ₄ gas,
PH ₃ / H ₂ gas was flowed into the deposition chamber 401. At this time, the flow rate of the SiH ₄ gas was ₂ sccm, and the flow rate of the H ₂ gas was 10 sccm.
Each mass flow controller was adjusted so that the flow rate of the PH ₃ / H ₂ gas was 200 sccm at 0 sccm.
The pressure in the deposition chamber 401 was adjusted opening of the conductance valve 407 so as to 1.0 Torr. The power of the RF power source was set to 0.01 W / cm ³ and the RF electrode 410
, A glow discharge is generated, a shutter is opened, the production of an n-type layer on the first p-type layer is started, and the shutter is closed when an n-type layer having a thickness of 30 nm is produced. The RF power was turned off, the glow discharge was stopped, and the formation of the n-type layer was completed. By closing the valve 2001,2004, SiH ₄ gas into the deposition chamber 401, PH ₃ / H ₂ gas flow into the <br/> and stopper of continued flow compost H ₂ gas for 5 minutes into a product chamber 401
After closing the outflow valves 2003, it was evacuated deposition chamber 及 beauty gas pipe 401.

To form the Si layer, the valve 2003 is gradually opened, H ₂ gas is introduced into the deposition chamber 401 through the introduction pipe 411, and the mass flow controller 2013 is set so that the H ₂ gas flow rate becomes 50 sccm. Then, the conductance valve was adjusted so that the pressure in the deposition chamber became 1.5 Torr, and the heater 405 was set so that the temperature of the substrate 404 became 270 ° C. When the substrate temperature was stabilized, the valve 2001 was further opened gradually, and SiH ₄ gas was introduced into the deposition chamber 401. At this time, the flow rate of the SiH ₄ gas was ₂ sccm, and the flow rate of the H ₂ gas was 10 sccm.
Each mass flow controller was adjusted to be 0 sccm. The pressure in the deposition chamber 401 is 1.5 Torr
The opening of the conductance valve 407 was adjusted to be r. The power of the RF power source was set to 0.01 W / cm ³ , RF power was introduced to the RF electrode 410 to generate glow discharge, the shutter was opened, the formation of a Si layer on the n-type layer was started, and the deposition rate was increased. 0.15 nm / sec, layer thickness 10 n
Close the shutter was to prepare a Si layer of m, RF
The power was turned off, the glow discharge was stopped, and the formation of the Si layer was completed. When the valve 2001 is closed, the Si
H ₄ gas and stopper the flow rate of the H ₂ gas into the sedimentary chamber 401 5 minutes
After it continued to flow during closing the outflow valves 2003, deposition chamber 4
It was evacuated 及 beauty gas in the pipe 01.

Next, to manufacture an i-type layer, the valve 20
03 was gradually opened, H ₂ gas was introduced into the deposition chamber 401, and the mass flow controller 2013 adjusted the H ₂ gas flow rate to 300 sccm. Becomes deposition chamber pressure 0.01Torr as adjusted by conductance valve, to set the heater 405 so that the temperature of the substrate 404 is 350 ° C., further gradually valve 2001 and 2002 where the substrate temperature became stable Open, Si
H ₄ gas and CH ₄ gas were caused to flow into the deposition chamber 401. At this time, SiH ₄ gas flow rate of 100 sccm, CH ₄ gas flow rate 30 sccm, H ₂ gas flow rate was adjusted with mass flow controllers each so that 300 sccm.
The opening of the conductance valve 407 was adjusted so that the pressure in the deposition chamber 401 became 0.01 Torr. Then ,
The power of the RF power supply 403 is set to 0.40 W / cm ³ ,
The voltage was applied to the RF electrode 403. Thereafter, the power of a μW power supply (not shown) is set to 0.20 W / cm ³ and the dielectric window 413 is set.
Introducing a μW power into the deposition chamber 401 through to cause glow discharge, opening the shutter was started the production of i-type layer on the Si layer. Using a computer connected to a mass flow controller, the flow rates of SiH ₄ gas and CH ₄ gas were changed according to the flow rate change pattern shown in FIG.
When the i-type layer having a thickness of 300 nm was formed , the shutter was closed, the μW power supply was turned off to stop glow discharge, the RF power supply 403 was turned off, and the preparation of the i-type layer was completed. Valve 200
Close 1,2002, SiH ₄ gas into the deposition chamber 401, CH ₄ gas and stopper influx, after continuously introduced compost H ₂ gas for 5 minutes into a product chamber 401, closing the valve 2003, the deposition chamber The inside of 401 and the inside of the gas pipe were evacuated.

Next, in order to form a second p-type layer, the valve 2003 was gradually opened, H ₂ gas was introduced into the deposition chamber 401, and the mass flow controller was adjusted so that the H ₂ gas flow rate became 300 sccm. Adjusted in 2013. Pressure in the deposition chamber was adjusted with conductance valve to be 0.02 Torr, and setting the heater 405 so that the temperature of the substrate 404 is 200 ° C., further valve at the substrate temperature became stable 2001,2002,2005
Is gradually opened, and SiH ₄ gas, CH ₄ gas, H ₂ gas,
B ₂ H ₆ / H ₂ gas was caused to flow into the deposition chamber 401. At this time, the flow rate of the SiH ₄ gas was 10 sccm, the flow rate of the CH ₄ gas was 5 sccm, the flow rate of the H ₂ gas was 300 sccm, and B ₂ H ₆ /
Each mass flow controller was adjusted so that the flow rate of H ₂ gas became 10 sccm. Pressure in the deposition chamber 401
And adjusting the opening of the conductance valve 407 as will be 0.02 Torr. 0.30W power of μW power supply
/ Cm ³ and the deposition chamber 40 through the dielectric window 413.
1, a glow discharge is generated, a shutter 415 is opened, and a lightly doped layer (A) is formed on the i-type layer.
Layer) has begun. When the layer A having a thickness of 3 nm was formed, the shutter was closed, the μW power was turned off, and the glow discharge was stopped. The valves 2001 , 2002 , and 2005 are closed, and SiH ₄ gas, CH ₄ gas , B ₂
H ₆ / H ₂ gas and stopper influx, after continued to flow compost 5 minutes H ₂ gas into the product chamber 401, closing the valve 2003 was evacuated deposition chamber 及 beauty gas pipe 401.

Next, the valve 2005 was gradually opened, B ₂ H ₆ / H ₂ gas was introduced into the deposition chamber 401, and the flow rate was adjusted to 1000 sccm by each mass flow controller. The pressure in the deposition chamber 401 is 0.0
The opening of the conductance valve 407 was adjusted to 2 Torr, the power of the μW power supply was set to 0.20 W / cm ³ , and the power of μW was introduced into the deposition chamber 401 through the dielectric window 413.
Electric power is introduced to cause glow discharge, and the shutter 41
5 was opened, and the formation of boron (B layer) on the A layer was started.
After 6 seconds, the shutter was closed, the μW power supply was turned off, and glow discharge was stopped. The valve 2005 is closed to stop the flow of the B ₂ H ₆ / H ₂ gas into the deposition chamber 401.
After continuously flowing the H ₂ gas into the deposition chamber 401 for minutes, the valve 2003 was closed, and the inside of the deposition chamber 401 and the inside of the gas pipe were evacuated.

Next , an A layer is formed on the B layer by the same method, conditions and procedures as those described above, and a B layer and an A layer are further laminated to form a second p-type layer having a thickness of about 10 nm. Finished forming. Next, on the second p-type layer, as a transparent electrode, a layer thickness of 70 nm
And vacuum deposition of _{ITO (In 2 O 2 + S} nO 2) a conventional vacuum deposition method. Then, a collector electrode layer thickness 5μm composed of silver (Ag) on the transparent electrode was vacuum deposited by conventional vacuum deposition method.

Next, a 3 μm-thick back electrode made of an Ag—Ti alloy was vacuum-deposited on the back surface of the substrate by a usual vacuum deposition method. Thus, the fabrication of this solar cell was completed. This solar cell is referred to as (SC Ex. 33), and the manufacturing conditions of the first p-type layer, the n-type layer, the Si layer, the i-type layer, and the second p-type layer are shown in Table 12.
Shown in

(Comparative Example 33-1) Example 33 was repeated except that the SiH ₄ gas flow rate and the CH ₄ gas flow rate were adjusted by the respective mass flow controllers according to the flow rate patterns shown in FIG. 6 when forming the i-type layer. A solar cell was produced under the same conditions and under the same procedure as described above. This solar cell (SC ratio 33-
Let's call it 1).

(Comparative Example 33-2) A solar cell was manufactured under the same conditions and in the same procedure as in Example 33 except that the μW power was changed to 0.5 W / cm ³ when forming the i-type layer. This solar cell is referred to as (SC ratio 33-2). (Comparative Example 33-3) A solar cell was fabricated under the same conditions and in the same procedure as in Example 33 except that the RF power was changed to 0.15 W / cm ³ when forming the i-type layer. This solar cell is referred to as (SC ratio 33-3).

(Comparative Example 33-4) When forming an i-type layer, μW power was 0.5 W / cm ³ and RF power was 0.55
A solar cell was manufactured under the same conditions and in the same procedure as in Example 33 except that W / cm ³ was used. This solar cell (SC ratio 3
3-4). (Comparative Example 33-5) A solar cell was manufactured under the same conditions and in the same procedure as in Example 33 except that the pressure in the deposition chamber was set to 0.08 Torr when forming the i-type layer. This solar cell is referred to as (SC ratio 33-5).

(Comparative Example 33-6) Example 3 was repeated except that the deposition rate was 3 nm / sec when forming the Si layer.
A solar cell was manufactured under the same conditions and under the same procedure as in No. 3. This solar cell will be called (SC Comp. 33-6). (Comparative Example 33-7) When forming the Si layer, the thickness was set to 40.
A solar cell was manufactured under the same conditions and in the same procedure as in Example 33 except that the thickness was changed to nm. This solar cell (SC ratio 33-
7).

The initial light conversion efficiency (photovoltaic power / incident light power) and durability characteristics of the manufactured solar cells (SC Ex 33) and (SC Comp. 33-1) to (SC Comp. 33-7) were measured. . As a result of the measurement, the initial photoelectric conversion efficiencies of (SC ratio 33-1) to (SC ratio 33-7) with respect to the solar cell of (SC Ex 33) were as follows.

(SC ratio 33-1) 0.78 times (SC ratio 33-2) 0.63 times (SC ratio 33-3) 0.80 times (SC ratio 33-4) 0.65 times (SC ratio) 33-5) 0.77 times (SC ratio 33-6) 0.82 times (SC ratio 33-7) 0.86 times When the durability characteristics were measured, the solar cell of (SC actual 33) was measured. , (SC ratio 33-1) to (SC ratio 33-
The durability characteristics of 7) were as follows.

(SC ratio 33-1) 0.79 times (SC ratio 33-2) 0.71 times (SC ratio 33-3) 0.78 times (SC ratio 33-4) 0.70 times (SC ratio) 33-5) 0.72 times (SC ratio 33-6) 0.83 times (SC ratio 33-7) 0.89 times Next, based on the relationship between the composition ratio of Si atoms and C atoms and the band gap, the i-type layer was obtained. And the change in the band gap in the thickness direction of the Si layer were determined.
In the solar cells of 2) to (SC ratio 33-7), the position of the minimum value of the band gap is shifted toward the p / i interface from the center position of the i-type layer, and the solar cell of (SC ratio 33-1) In the battery, it was found that the position of the minimum value of the band gap was more deviated toward the i / Si interface than the center position of the i-type layer.

As described above, (SC actual 33), (SC ratio 33−
The changes in the band gap in the layer thickness direction of 1) to (SC ratio 33-7) are caused by the source gas containing Si (in this case, SiH ₄ gas) and the source gas containing C (this In some cases, it depends on the flow rate ratio of CH ₄ gas). Next, a second p-type layer having a laminated structure was formed on the polycrystalline silicon substrate, and a TEM (transmission electron microscope) image thereof was observed. A second p-type layer was formed on a substrate by the same method and procedure as in Example 33 except that the deposition time of the B layer was changed to 12 seconds. Cut the prepared sample in the cross-sectional direction,
When observing the state of lamination of the A layer and the B layer in the second p-type layer, as shown in FIG. 21, the B layer having a thickness of about 1 nm and the A layer having a thickness of about 3 nm are alternately laminated. I understood that.

(Comparative Example 33-8) Several solar cells were manufactured in the same manner as in Example 33 except that the μW power and the RF power introduced when forming the i-type layer were variously changed. The relationship between the μW power and the deposition rate shows the same tendency as in FIG. 9, and the deposition rate does not depend on the RF power.
It was constant at 2 W / cm ³ or more, and it was found that the SiH ₄ gas and the CH ₄ gas, which are the source gases, were decomposed 100% by this electric power. When the initial photoelectric conversion efficiency of the solar cell when irradiated with AM1.5 (100 mW / cm ² ) light was measured, the result shown in FIG. 10 was obtained. That is, μ
W power is not more than μW power (0.32 W / cm ³ ) for decomposing 100% of SiH ₄ gas and CH ₄ gas, and RF
It was found that the initial photoelectric conversion efficiency was significantly improved when the power was larger than the μW power.

(Comparative Example 33-9) When forming the i-type layer in Example 33, the flow rate of the gas introduced into the deposition chamber 401 was changed to Si.
H ₄ gas 50 sccm, and change the CH ₄ gas 10 sccm, H ₂ gas is not introduced, it was several to produce a solar cell variously changing the μW power and RF power. Other conditions were the same as in Example 33. The relationship between the deposition rate, the μW power, and the RF power was examined. As in Comparative Example 33-8, the deposition rate did not depend on the RF power, and the μW power was 0.18 W / cm ^3.
The above is constant, and at this μW electric power, the raw material gas Si
H ₄ gas and CH ₄ gas were found to be 100% decomposed. When the initial photoelectric conversion efficiency of the solar cell when irradiating AM1.5 light was measured, the result showed the same tendency as FIG. That is, μW power is SiH
It was found that the initial photoelectric conversion efficiency was significantly improved when the power was less than the μW power (0.18 W / cm ³ ) for decomposing 100% of the ₄ gas and CH ₄ gas and the RF power was larger than the μW power.

(Comparative Example 33-10) In forming the i-type layer in Example 33, the flow rate of the gas introduced into the deposition chamber 401 was set to S.
iH ₄ gas 200 sccm, CH ₄ gas 50 sccm,
H ₂ gas was changed to 500 sccm and the substrate temperature was 3
Change the heater setting so that the temperature becomes
Several solar cells were fabricated with various power and RF powers. Other conditions were the same as in Example 33.

The relationship between the deposition rate, the μW power, and the RF power was examined.
The μW power was constant at 0.65 W / cm ³ or more without depending on the power, and it was found that the SiH ₄ gas and CH ₄ gas as the source gas were decomposed 100% by this power.
When the initial photoelectric conversion efficiency of the solar cell when irradiating AM1.5 light was measured, the result showed the same tendency as FIG. That, .mu.W power the SiH ₄ gas 100
It was found that the initial photoelectric conversion efficiency was greatly improved when the power was not more than the μW power (0.65 W / cm ³ ) at which the% decomposition was performed and the RF power was larger than the μW power.

(Comparative Example 33-11) In forming the i-type layer in Example 33, the pressure in the deposition chamber was increased from 3 mTorr to 20 mbar.
Various conditions were changed up to 0 mTorr, and other conditions were the same as in Example 33.
Some solar cells were produced in the same manner as described above. AM1.5
When the initial photoelectric conversion efficiency of the solar cell when irradiating light was measured, the result was as shown in FIG.
It was found that the initial photoelectric conversion efficiency was greatly reduced at Torr or higher.

(Comparative Example 33-12) In forming the Si layer in Example 33, the deposition rate was changed variously by changing the SiH ₄ gas flow rate and RF power, and the other conditions were the same as in Example 33. Some solar cells were produced. AM
When the initial photoelectric conversion efficiency of the solar cell when irradiating 1.5 light was measured, the deposition rate of the Si layer was 2 nm / sec.
From the above, it was found that the initial photoelectric conversion efficiency was greatly reduced.

(Comparative Examples 33-13) In forming the Si layer in Example 33, several solar cells were produced by changing the layer thickness variously and using the other conditions as in Example 33. AM1.
Measurement of the initial photoelectric conversion efficiency of the solar cell when five light beams were irradiated showed that the initial photoelectric conversion efficiency was greatly reduced when the layer thickness was 30 nm or more.

As described above, (Comparative Example 33-1) to (Comparative Example 33)
-13), the solar cell of the present invention (SC Ex. 3)
It was demonstrated that 3) had more excellent characteristics than conventional solar cells (SC ratio 33-1) to (SC ratio 33-7). (Embodiment 34) The band gap (E
g) producing several solar cells by changing the position of the minimum value in the layer thickness direction, the size of the minimum value, and the pattern,
The initial photoelectric conversion efficiency and durability characteristics were examined in the same manner as in Example 33. At this time, a solar cell having the band gap shown in FIG. 12 was produced in the same manner as in Example 33 except for the change pattern of the SiH ₄ gas flow rate and the CH ₄ gas flow rate of the i-type layer.

Table 13 shows the results obtained by examining the initial photoelectric conversion efficiency and the durability of these solar cells (the values in the table are based on SC Example (34-1)). As can be seen from these results, the magnitude of the minimum value of the band gap,
Regardless of the change pattern, the band gap of the i-type layer changes smoothly in the layer thickness direction, and the position of the minimum value of the band gap is shifted from the center position of the i-type layer toward the p / i interface. It turns out that solar cells are better.

(Example 35) A solar cell in which the layer B was formed by a mercury-sensitized CVD method was manufactured. Φ10 in the deposition chamber of FIG.
A quartz glass window having a thickness of 0 mm and a thickness of 10 mm and a low-pressure mercury lamp were attached, and light from the low-pressure mercury lamp was allowed to enter the deposition chamber through the quartz glass window. Further, a shutter (window shutter) for covering the quartz glass window was provided inside the deposition chamber so that the deposits did not adhere. Furthermore, mercury (purity: 99.999%) was packed in a liquid cylinder 2048 having a valve at the entrance and exit. Install the cylinder between the valve 2005 and the mass flow controllers 2015, by bubbling with B ₂ H ₆ / H ₂ gas, and to be able to introduce the mercury vaporized with B ₂ H ₆ / H ₂ gas into the deposition chamber.

When forming the B layer, the flow rate of the B ₂ H ₆ / H ₂ gas was set to 1000 sccm, the pressure was set to 1.0 Torr, the shutter 415 was opened in advance, the low-pressure mercury lamp was turned on, and the window shutter was opened for 60 seconds. FIG. 1 shows the same conditions, method and procedure as in Example 33 except that the layer B was formed on the layer A by opening.
Was manufactured. Solar cell (SC actual 3)
5) was found to have better initial photoelectric conversion efficiency and durability than conventional solar cells (SC ratio 33-1) to (SC ratio 33-7), similarly to (SC Ex 33).

Example 36 A solar cell shown in FIG. 1-b was fabricated using a p-type polycrystalline silicon substrate. A first n-type layer, a p-type layer, an i-type layer, a Si layer, and a second n-type layer were sequentially formed on a substrate. Table 14 shows the forming conditions. When forming the i-type layer, the flow rate of the SiH ₄ gas and the flow rate of the CH ₄ gas are changed as shown in the pattern of FIG. 0.
It was set to 15 nm / sec. The layers other than the substrate and the semiconductor layer were manufactured using the same conditions and the same method as in Example 33.

The manufactured solar cell (SC Ex. 36) is (SC
As in Example 33), conventional solar cells (SC ratio 33-1)-
It was found to have better initial photoelectric conversion efficiency and durability than (SC ratio 33-7). (Example 37) A solar cell having the maximum value of the band gap of the i-type layer near the p / i interface and having a thickness of 20 nm in the region was used as the flow rate change pattern of the i-type layer shown in FIG. It was produced using.

An i-type layer was manufactured under the same conditions and the same method as in Example 33 except that the flow rate change pattern was changed. Next, the composition analysis of the solar cell was performed in the same manner as in Example 1, and the change in the band gap in the layer thickness direction of the i-type layer was examined from the relationship between the band gap and the composition. The result was. The prepared (SC Ex 37) is (SC
As in Example 33), conventional solar cells (SC ratio 33-1)-
It was found to have better initial photoelectric conversion efficiency and durability than (SC ratio 33-7).

(Comparative Example 37) There was a region having the maximum band gap near the p / i interface of the i-type layer, and several solar cells were manufactured with various thicknesses of the region. Except for the thickness of the region, it was manufactured using the same conditions and the same method as in Example 37. When the initial photoelectric conversion efficiency and durability of the manufactured solar cell were measured, the thickness of the region was 1 nm.
Above 30 nm or less, the solar cell (SC
Even better initial photoelectric conversion efficiency and durability than in Example 33) were obtained.

(Example 38) The band gap of the i-type layer has a maximum value near the i / Si interface, and the thickness of the region is 1
A solar cell having a thickness of 5 nm was manufactured using the flow rate change pattern of the i-type layer shown in FIG. Except for changing the flow rate change pattern of the i-type layer, it was manufactured using the same conditions and the same method as in Example 33. Next, the composition of the solar cell was analyzed in Example 33.
When the change in the band gap in the thickness direction of the i-type layer was examined in the same manner as in the above, the result was similar to that in FIG. The manufactured solar cell (SC Ex. 38) is (SC Ex. 3)
Similar to 3), conventional solar cells (SC ratio 33-1) to (S
It was found to have better initial photoelectric conversion efficiency and durability than C ratio 17).

(Comparative Example 38) There was a region having the maximum band gap near the i / Si interface of the i-type layer, and several solar cells were produced with various thicknesses of the region. Except for the thickness of the region, it was manufactured using the same conditions and the same method as in Example 38. When the initial photoelectric conversion efficiency and durability of the manufactured solar cell were measured, the thickness of the region was 1 nm.
As described above, when the thickness is 30 nm or less, even better initial photoelectric conversion efficiency and durability than the solar cell of Example 33 (SC Ex 33) were obtained.

(Example 39) In forming the second p-type layer, triethyl boron (abbreviated as (B (C ₂ H ₅ ) ₃ , TEB)) was used instead of B ₂ H ₆ / H ₂ gas. A solar cell was fabricated using TEB (purity 9) at room temperature and in normal thickness and in liquid form.
(9.99%) was packed in a liquid cylinder 2048 with valves at the inlet and outlet. The bomb was attached to the source gas supply device and bubbled with H ₂ gas, so that the TEB vaporized together with the H ₂ gas could be introduced into the deposition chamber.

When forming the A layer, TEB / H_Two1 gas
Example 33 except that 0 sccm was allowed to flow into the deposition chamber.
An A layer is formed on the i-type layer under the same conditions and procedure, and H
_TwoThe gas was evacuated after flowing the gas into the deposition chamber. Layer B
When forming TEB / H_Two1000 sccm of gas,
The same conditions and hands as in Example 33 except that it was allowed to flow into the deposition chamber
A layer B is formed on the i-type layer in order, and _TwoDeposit gas
After flowing into the room, the chamber was evacuated.

Next, an A layer was formed on the B layer, and H _{2 was applied for} 5 minutes.
The gas was evacuated after flowing the gas into the deposition chamber. Then A
A layer B was formed on the layer, and H ₂ gas was allowed to flow into the deposition chamber for 5 minutes, followed by evacuation. Next, the A layer was formed on the B layer, and H ₂ gas was allowed to flow into the deposition chamber for 5 minutes, followed by evacuation.

Except for the second p-type layer, it was manufactured under the same conditions, method and procedure as in Example 33. The manufactured (SC Ex. 39) is the same as the (SC Ex.
1) It was found to have better initial photoelectric conversion efficiency and durability than (SC ratio 33-7). (Example 40) A solar cell having an i-type layer containing oxygen atoms was produced. When forming the i-type layer, the same conditions, the same method, and the same procedure as in Example 33 were used except that O ₂ / He gas was introduced into the deposition chamber 401 at 10 sccm in addition to the gas flowing in Example 33. . Solar cell (SC actual 4)
0) was found to have better initial photoelectric conversion efficiency and durability than conventional solar cells (SC ratio 33-1) to (SC ratio 33-7), similarly to (SC Ex 33).

Further, the content of oxygen atoms in the i-type layer was determined by SI
As a result of examination by MS, it was contained almost uniformly, and 2 × 10 ¹⁹
(Pieces / cm ² ). Example 41 A silicon solar cell having an i-type layer containing nitrogen atoms was manufactured. When forming the i-type layer, NH ₃ / H ₂ gas is supplied at 5 scc in addition to the gas flowing in Example 33.
m, the same conditions, the same method, and the same procedure as in Example 33 were used, except that they were introduced into the deposition chamber 401. The manufactured solar cell (SC Ex. 41) has better initial photoelectric conversion efficiency and durability than the conventional solar cells (SC Comp. 33-1) to (SC Comp. 33-7), similarly to (SC Ex. 33). It was found to have. Further, the content of nitrogen atoms in the i-type layer is determined by SI
As a result of examination by MS, it was contained almost uniformly, and 3 × 10 ¹⁷
(Pieces / cm ² ).

Example 42 Oxygen atoms and nitrogen atoms were added to the i-type layer.
A solar cell containing elemental atoms was produced. i-type layer
When forming, in addition to the gas flowing in Example 33, O_Two/ He
5 sccm gas, NH_Two/ H_Two5 sccm of gas
The same conditions as in Example 33 except that they are introduced into the storage chamber 401,
The same method and the same procedure were used. The fabricated solar cell (SC
Ex. 42) is similar to (SC Ex. 33) in that the conventional solar cell (S
Even better than C ratio 33-1) to (SC ratio 33-7)
Have high initial photoelectric conversion efficiency and durability
Was. Also, the content of oxygen atoms and nitrogen atoms in the i-type layer
When examined by SIMS, it was found to be almost uniformly contained.
1 × 10¹⁹(Pcs / cm^Two), 3 × 10¹⁷(Pcs / cm
^Two).

(Example 43) A solar cell was manufactured in which the hydrogen content of the i-type layer was changed corresponding to the silicon content. The O ₂ / He gas cylinder was filled with SiF ₄ gas (purity 99.
When the i-type layer is formed by replacing the cylinder with a cylinder, FIG.
According to the flow pattern of 5-a, SiH ₄ gas, CH ₄
The flow rates of the gas and the SiF ₄ gas were changed. The change in band gap in the layer thickness direction of this solar cell (SC Ex 43) was determined by the same method as in Example 33.
The result was similar to b.

Further, the content of hydrogen atoms and silicon atoms was analyzed in the thickness direction using a secondary ion mass spectrometer. A result similar to that of FIG. 15C was obtained, and it was found that the hydrogen atom content had a distribution in the layer thickness direction corresponding to the silicon atom content. This solar cell (SC actual 43)
The initial photovoltaic conversion efficiency and durability characteristics of the conventional solar cell (SC ratio 33-
It was found to have better initial photoelectric conversion efficiency and durability than 1) to (SC ratio 33-7).

Example 44 When a semiconductor layer of the solar cell of FIG. 1 was formed by the manufacturing apparatus using the microwave plasma CVD method shown in FIG.
Example 33 except that H ₄ gas) and a carbon atom-containing gas (CH ₄ gas) were mixed at a distance of 1 m from the deposition chamber.
A solar cell (SC Ex. 44) was produced in the same manner and in the same procedure as described above. The manufactured solar cell (SC actual 44) is (SC actual 3)
It was found to have better initial photoelectric conversion efficiency and durability than 3).

Example 45 A first p-type layer was formed by a gas diffusion method, and when forming an i-type layer, a C ₂ H ₂ gas was used instead of a CH ₄ gas, and a positive electrode was used for an RF electrode. A solar cell was manufactured by applying a DC bias and changing the RF power, the DC bias, and the μW power. First, the O ₂ / He gas cylinder was replaced with a BBr ₃ (BBr ₃ / H ₂ gas) cylinder diluted to 10% with hydrogen, and the CH ₄ gas cylinder was replaced with C ₂ H.
Replaced with _two gases. When forming the first p-type layer, a substrate temperature of 900 ° C., a BBr ₃ / H ₂ gas flow rate of 500 sccm,
B was diffused under the diffusion conditions of an internal pressure of 30 Torr. When the junction depth reached 300 nm, the introduction of the BBr ₃ / H ₂ gas was stopped. On the other hand, when forming the i-type layer, C ₂ H ₂ gas was introduced instead of CH ₄ gas, and the flow rate was changed according to the flow pattern as shown in FIG. Further, as shown in FIG. 16, the RF power, the DC bias, and the μW power were changed.
Except for the first p-type layer and the i-type layer, the same conditions, the same method, and the same procedure as in Example 33 were used.

The fabricated solar cell (SC Ex 45) is (SC
As in Example 33), conventional solar cells (SC ratio 33-1)-
It was found to have better initial photoelectric conversion efficiency and durability than (SC ratio 33-7). Example 46 The triple solar cell shown in FIG. 17 was manufactured using the manufacturing apparatus shown in FIG. 4 using the microwave plasma CVD method of the present invention.

As a substrate, an n-type polycrystalline silicon substrate manufactured by a casting method was used. 50 × 50m
One surface of the m ² substrate was immersed in a 1% aqueous NaOH solution at a temperature of 100 ° C. for 5 minutes, and washed with pure water. Observation of the surface immersed in NaOH with a scanning electron microscope (SEM) revealed that irregularities having a pyramid structure were formed on the surface, and that the substrate was textured. Next, the substrate was ultrasonically washed with acetone and isopropanol, further washed with pure water, and dried with warm air.

Water was prepared in the same procedure and in the same manner as in Example 33.
Elementary plasma treatment and the first surface on the textured surface of the substrate
And a first n-type layer, a first i-type layer
Layer, second p-type layer, second n-type layer, Si layer, second i-type
A layer and a third p-type layer were sequentially formed. Form a second i-type layer
At the time, the SiH
_FourGas flow, CH_FourChange the gas flow rate to deposit the Si layer
The speed was 0.15 nm / sec. The third p-type layer is actually
As in Example 33, a laminated structure was used.

Next, as in Example 33, a 70 nm-thick ITO (In ₂ O) layer was formed on the third p-type layer as a transparent electrode.
₃ + SnO ₂ ) was vacuum-deposited by a normal vacuum deposition method. Next, as in Example 33, a 5 μm-thick current collecting electrode made of silver (Ag) was vacuum-deposited on the transparent electrode by a normal vacuum deposition method. Next, similarly to Example 33, the Ag-T
A 3 μm-thick back electrode made of an i-alloy was vacuum-deposited by a normal vacuum deposition method.

Thus, the fabrication of the triple type solar cell using the microwave plasma CVD method is completed. This solar cell is referred to as (SC Ex. 46), and Table 15 shows the manufacturing conditions of each semiconductor layer. (Comparative Example 46-1) A method similar to that in Example 46 except that the flow rate of the SiH ₄ gas and the flow rate of the CH ₄ gas were changed in accordance with the flow rate change pattern of FIG. 6 when forming the second i-type layer of FIG. A triple solar cell was manufactured in the same procedure. This solar cell is referred to as (SC ratio 46-1).

(Comparative Example 46-2) When forming the second i-type layer of FIG. 17, a triple was performed by the same method and the same procedure as in Example 46 except that the μW power was changed to 0.5 W / cm ^3. A solar cell was fabricated. This solar cell (SC ratio 46-2)
I will call it. (Comparative Example 46-3) When forming the second i-type layer in FIG. 17, a triple type solar cell was manufactured in the same manner as in Example 46 except that the RF power was set to 0.15 W / cm ^3. Was prepared. This solar cell is referred to as (SC ratio 46-3).

[0352] (Comparative Example 46-4) when forming the second i-type layer in FIG. 17, except that the μW power 0.5 W / cm ^3, the RF power to 0.55 W / cm ³ Example 46 A triple-type solar cell was produced in the same manner and in the same procedure. This solar cell is referred to as (SC ratio 46-4).

(Comparative Example 46-5) When forming the second i-type layer in FIG. 17, the pressure in the deposition chamber 401 was set to 0.08 Torr.
A triple solar cell was produced in the same manner and in the same procedure as in Example 46 except that This solar cell is referred to as (SC ratio 46-5). (Comparative Example 46-6) A triple solar cell was manufactured in the same manner as in Example 46, except that the deposition rate was 3 nm / sec when forming the Si layer in FIG. This solar cell is referred to as (SC ratio 46-6).

(Comparative Example 46-7) A triple type solar cell was manufactured in the same manner and by the same procedure as in Example 46 except that the thickness of the Si layer in FIG. 17 was changed to 40 nm.
This solar cell is referred to as (SC ratio 46-7).
The initial photoelectric conversion efficiency and durability of these fabricated triple solar cells were measured in the same manner as in Example 33.
It was found to have better initial photoelectric conversion efficiency and durability than the ratios 46-1) to (SC ratio 46-7).

(Example 47) The solar cell of Example 33 was manufactured by using the manufacturing apparatus of FIG. 4 using the microwave plasma CVD method of the present invention, modularized, and applied to a power generation system. A 50 × 50 nm ² solar cell (SC Ex.
Five were produced. E on a 5.0 mm thick aluminum plate
An adhesive sheet made of VA (ethylene vinyl acetate) was placed thereon, a nylon sheet was placed thereon, and the solar cells produced were further arranged thereon to perform serialization and parallelization. An EVA adhesive sheet was placed thereon, and a fluororesin sheet was further placed thereon, and vacuum-laminated to form a module. The initial photoelectric conversion efficiency of the manufactured module was measured in the same manner as in Example 33.
The module was connected to the circuit showing the power generation system of FIG. 18, and an external light that was lit at night was used for the load. The entire system was powered by the battery and the power of the module, and the module was installed at an angle that could best collect sunlight. 1
The photoelectric conversion efficiency after a lapse of one year was measured, and the light deterioration rate (photoelectric conversion efficiency after one year / initial photoelectric conversion efficiency) was obtained. This module will be called (MJ actual 47).

(Comparative Example 47-1) Conventional solar cell (SC)
Sixty-five ratios 33-X) (X: 1 to 7) were produced under the same conditions, the same method, and the same procedure as in Comparative Example 33-X, and were modularized as in Example 47. This module (MJ ratio 4
7-X). Under the same conditions, the same method, and the same procedure as in Example 47, the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after one year had elapsed were measured, and the light deterioration rate was obtained.

As a result, the light degradation rate of (MJ ratio 47-X) was as follows with respect to (MJ actual 47). Module Light degradation rate ratio Ｍ MJ actual 47 1.00 MJ ratio 47-1 0.76 MJ ratio 47-2 0.72 MJ ratio 47-3 0.86 MJ ratio 47-4 0.70 MJ ratio 47-5 0.82 MJ ratio 47-6 0.70 MJ ratio 47-7 0.83 It was found that the solar cell module had more excellent light degradation characteristics than the conventional solar cell module.

(Example 48) Microwave plasm of the present invention
Using the manufacturing apparatus shown in FIG.
The solar cell of FIG. 19 having the second Si layer at the interface was fabricated.
Was. Manufactured by the casting method as in Example 33.
Built 50 × 50mm ^TwoN-type polycrystalline silicon substrate
HF and HNO_Three(H_TwoAqueous solution (diluted to 10% with O)
For several seconds and washed with pure water. Then acetone and isop
Ultrasonic cleaning with lopanol, further cleaning with pure water, warm air
Let dry.

Hydrogen plasma treatment was performed in the same procedure and in the same manner as in Example 33 to form a first p-type layer on the substrate, and further a first n-type layer, a first Si layer, and an i-type Layer, second
, And a second p-type layer were sequentially formed. When forming the i-type layer, the flow rate of the SiH ₄ gas and the flow rate of the CH ₄ gas are changed according to the flow rate change pattern as shown in FIG. 13A, and the deposition rate of the first Si layer and the second Si layer is 0.15 nm. / Se
c, The layer thickness was 10 nm. Note that the second p-type layer had a laminated structure as in Example 33.

Next, on the second p-type layer, a 70 nm-thick ITO (In) layer was formed as a transparent electrode in the same manner as in Example 33.
₂ O ₃ + SnO ₂ ) was vacuum deposited by a normal vacuum deposition method. Next, as in Example 33, silver (Ag) was formed on the transparent electrode.
A 5 μm-thick current collecting electrode made of was vacuum-deposited by an ordinary vacuum deposition method. Next, as in Example 33, A
A back electrode made of a g-Ti alloy and having a thickness of 3 μm was vacuum-deposited by a normal vacuum deposition method.

This solar cell will be referred to as (SC Ex. 48). Table 16 shows the manufacturing conditions of each semiconductor layer. The initial photoelectric conversion efficiency and the durability of the manufactured solar cell were measured by the same method as in Example 33.
As in Example 33), conventional solar cells (SC ratio 33-1)-
It was found to have better initial photoelectric conversion efficiency and durability than (SC ratio 33-7).

(Example 49) In this example, a photovoltaic element in which B and P atoms were contained in the i-type layer and the second p-type layer had a laminated structure was manufactured. First, to prepare the solar cell of FIG. 1-a using an n-type polycrystalline silicon substrate fabricated by Cass pos- sesses method.

A substrate having a size of 50 × 50 m ² and a thickness of 500 μm was immersed in an aqueous solution of HF and HNO ₃ (diluted to 10% with H ₂ O) for several seconds and washed with pure water. Next, ultrasonic cleaning with acetone and Lee Sopuro <br/> propanol, washed with pure water to further, dried hot air. Next, a source gas supply device 2000 shown in FIG.
And a deposition apparatus 400, a semiconductor layer was formed on the substrate by a manufacturing apparatus using a glow discharge decomposition method. less than,
The manufacturing procedure will be described.

[0364] In the gas cylinders 2041 to 2047 in the figure, the same raw material gas as in the first embodiment is sealed. After the preparation for film formation is completed in the same manner as in Example 1, the substrate is subjected to hydrogen plasma treatment, and then the first p
A mold layer, an n-type layer, a Si layer, an i-type layer, and a second p-type layer were formed.

First, to perform the hydrogen plasma treatment, the valve 2003 was gradually opened, H ₂ gas was introduced into the deposition chamber 401, and the mass flow controller 2013 adjusted the H ₂ gas flow rate to 500 sccm. The conductance valve is adjusted while watching the vacuum gauge 402 so that the pressure in the deposition chamber becomes 2.0 Torr, and the heater 405 is set so that the temperature of the substrate 404 becomes 550 ° C. Is closed, a microwave (μW) power supply is set to 0.20 W / cm ³ , a μW power is introduced, a glow discharge is generated, a shutter 415 is opened, and hydrogen plasma treatment of the substrate is performed. Started. After 10 minutes, the shutter was closed, the μW power supply was turned off, the glow discharge was stopped, and the hydrogen plasma treatment was completed. Deposition chamber 401 for 5 minutes
After the H ₂ gas was continuously flowed into the inside, the valve 2003 was closed, and the inside of the deposition chamber 401 and the inside of the gas pipe were evacuated.

Next, to form the first p-type layer, the valve 2003 was gradually opened, H ₂ gas was introduced into the deposition chamber 401, and the mass flow controller was adjusted so that the H ₂ gas flow rate became 50 sccm. Adjusted in 2013. Pressure in the deposition chamber was adjusted with conductance valve while watching the vacuum gauge 402 to be 2.0 Torr, and setting the heater 405 so that the temperature of the substrate 404 is 350 ° C., further where the substrate temperature became stable Valve 200
1, 2005, gradually open, SiH ₄ gas, B ₂ H ₆ /
H ₂ gas was introduced into the deposition chamber 401. At this time, Si
H ₄ gas flow rate is 5 sccm, H ₂ gas flow rate is 100 sccc
m and each of the mass flow controllers were adjusted so that the flow rate of the B ₂ H ₆ / H ₂ gas was 500 sccm. The pressure in the deposition chamber 401 vacuum gauge 4 so as to 2.0Torr
02, the opening of the conductance valve 407 was adjusted. Confirm that the shutter 415 is closed, set the RF power supply to 0.20 W / cm ³ , introduce RF power, cause glow discharge, open the shutter 415, and place the first p-type on the substrate. The formation of the layer was started. Layer thickness 1
Close the shutter was to prepare a first p-type layer of nm, turn off the RF power to stop the glow discharge, a first p
The formation of the mold layer was completed. By closing the valve 2001,2005, SiH ₄ gas into the deposition chamber 401, B ₂ H ₆ / H ₂ gas and stopper influx, after continued to flow compost 5 minutes H ₂ gas into the product chamber 401, the valve close 2003 was evacuated deposition chamber 及 beauty gas pipe 401.

To form an n-type layer, the auxiliary valve 40
8. Open the valve 2003 gradually, introduce H ₂ gas into the deposition chamber 401 through the gas introduction pipe 411, set the mass flow controller 2013 so that the H ₂ gas flow rate becomes 50 sccm, and set the pressure in the deposition chamber to 1 0.0Torr
r with the conductance valve so that the substrate 4
Heater 405 so that the temperature of 04 becomes 350 ° C.
It was set. When the substrate temperature became stable, the valves 2001 and 2004 were gradually opened, and SiH ₄ gas,
PH ₃ / H ₂ gas was flowed into the deposition chamber 401. At this time, the flow rate of the SiH ₄ gas was ₂ sccm, and the flow rate of the H ₂ gas was 10 sccm.
Each mass flow controller was adjusted so that the flow rate of the PH ₃ / H ₂ gas was 200 sccm at 0 sccm.
The opening of the conductance valve 407 was adjusted so that the pressure in the deposition chamber 401 became 1.0 Torr. The power of the RF power source was set to 0.01 W / cm ³ ,
0, RF power is introduced, a glow discharge is generated, a shutter is opened, and an n-type layer is formed on the first p-type layer.
Close the shutter was to prepare a n-type layer having a thickness of 30 nm, turn off the RF power, stop the glow discharge to complete the formation of the n-type layer. By closing the valve 2001,2004, SiH ₄ gas into the deposition chamber 401, PH ₃ / H ₂ gas and stopper influx was continuously supplied compost H ₂ gas for 5 minutes into a product chamber 401
After closing the outflow valves 2003, it was evacuated deposition chamber 及 beauty gas pipe 401.

To form the Si layer, the valve 2003 is gradually opened, H ₂ gas is introduced into the deposition chamber 401 through the introduction pipe 411, and the mass flow controller 2013 is set so that the H ₂ gas flow rate becomes 50 sccm. Then, the pressure in the deposition chamber was adjusted to 1.5 Torr by a conductance valve, and the heater 405 was set so that the temperature of the substrate 404 became 270 ° C. When the substrate temperature was stabilized, the valve 2001 was further opened gradually, and SiH ₄ gas was introduced into the deposition chamber 401. At this time, the flow rate of the SiH ₄ gas was ₂ sccm, and the flow rate of the H ₂ gas was 10 sccm.
Each mass flow controller was adjusted to be 0 sccm. The pressure in the deposition chamber 401 is 1.5 Torr
The opening of the conductance valve 407 was adjusted to be r. The power of the RF power source was set to 0.01 W / cm ³ , RF power was introduced to the RF electrode 410 to generate glow discharge, the shutter was opened, the formation of a Si layer on the n-type layer was started, and the deposition rate was increased. 0.15 nm / sec, layer thickness 10 n
Close the shutter was to prepare a Si layer of m, RF
The power was turned off, the glow discharge was stopped, and the formation of the Si layer was completed. When the valve 2001 is closed, the Si
H ₄ gas and stopper the flow rate of the H ₂ gas into the sedimentary chamber 401 5 minutes
After it continued to flow during closing the outflow valves 2003, deposition chamber 4
It was evacuated 及 beauty gas in the pipe 01.

Next, in order to manufacture an i-type layer, the valve 20 was used.
03 was gradually opened, H ₂ gas was introduced into the deposition chamber 401, and the mass flow controller 2013 adjusted the H ₂ gas flow rate to 300 sccm. Deposition chamber pressure
There was adjusted conductance valve to be 0.01 Torr, and setting the heater 405 so that the temperature of the substrate 404 is 350 ° C., further valves <br/> substrate temperature was stabilized 2001,2002,2004 , 200
5 is gradually opened, and SiH ₄ gas, CH ₄ gas, PH ₃ /
H ₂ gas and B ₂ H ₆ / H ₂ gas were flowed into the deposition chamber 401. At this time, SiH ₄ gas flow rate of 100 sccm, CH ₄
Gas flow rate is 30 sccm, H ₂ gas flow rate is 300 sccc
m, PH ₃ / H ₂ gas flow rate was adjusted to ₂ sccm and B ₂ H ₆ / H ₂ gas flow rate was adjusted to 5 sccm by each mass flow controller. The pressure in the deposition chamber 401 is 0.0
The opening of the conductance valve 407 was adjusted to 1 Torr. Next , the power of the RF power supply 403 is set to 0.4
The power was set to 0 W / cm ³ and applied to the RF electrode 403. Thereafter, the power of a not-shown μW power supply is set to 0.20 W / cm ³ , and μW power is introduced into the deposition 401 through the dielectric window 413 to generate a glow discharge, a shutter is opened, and i Preparation of the mold layer was started. Using a computer connected to a mass flow controller,
SiH ₄ gas, CH ₄ according flow change pattern shown in
When the i-type layer having a thickness of 300 nm was formed by changing the flow rate of the gas , the shutter was closed, the μW power supply was turned off to stop glow discharge, and the RF power supply 403 was turned off to complete the i-type layer formation. Valves 2001, 2002, 2004, 200
5 to close, SiH ₄ gas into the deposition chamber 401, CH ₄ gas, PH ₃ / H ₂ gas, B ₂ H ₆ / H ₂ and stopper the inflow of gas,
After continuously introduced compost 5 minutes H ₂ gas into the product chamber 401, closing the valve 2003, the deposition chamber and the gas pipe 401 was evacuated.

Next, to form the second p-type layer, the valve 2003 was gradually opened, H ₂ gas was introduced into the deposition chamber 401, and the mass flow controller was adjusted so that the H ₂ gas flow rate was 300 sccm. Adjusted in 2013. Pressure in the deposition chamber was adjusted with conductance valve to be 0.02 Torr, and setting the heater 405 so that the temperature of the substrate 404 is 200 ° C., further valve at the substrate temperature became stable 2001,2002,2005
Is gradually opened, and SiH ₄ gas, CH ₄ gas, H ₂ gas,
B ₂ H ₆ / H ₂ gas was caused to flow into the deposition chamber 401. At this time, the flow rate of the SiH ₄ gas was 10 sccm, the flow rate of the CH ₄ gas was 5 sccm, the flow rate of the H ₂ gas was 300 sccm, and B ₂ H ₆ /
Each mass flow controller was adjusted so that the flow rate of H ₂ gas became 10 sccm. The opening of the conductance valve 407 was adjusted so that the pressure in the deposition chamber 401 was 0.02 Torr. 0.30 μW power supply
W / cm ³ and the deposition chamber 4 through the dielectric window 413.
01, a glow discharge is generated, a shutter 415 is opened, and a lightly doped layer (A) is formed on the i-type layer.
Layer) has begun. When the layer A having a thickness of 3 nm was formed, the shutter was closed, the μW power was turned off, and the glow discharge was stopped. The valves 2001 , 2002 , and 2005 are closed, and SiH ₄ gas, CH ₄ gas , B ₂
H ₆ / H ₂ gas and stopper influx, after continued to flow compost 5 minutes H ₂ gas into the product chamber 401, closing the valve 2003 was evacuated deposition chamber 及 beauty gas pipe 401.

Next, the valve 2005 was gradually opened, B ₂ H ₆ / H ₂ gas was introduced into the deposition chamber 401, and the flow rate was adjusted to 1000 sccm by each mass flow controller. The pressure in the deposition chamber 401 is 0.0
The opening of the conductance valve 407 was adjusted to 2 Torr, the power of the μW power supply was set to 0.20 W / cm ³ , and the power of μW was introduced into the deposition chamber 401 through the dielectric window 413.
Electric power is introduced to cause glow discharge, and the shutter 41
5 was opened, and the formation of boron (B layer) on the A layer was started.
After 6 seconds, the shutter was closed, the μW power supply was turned off, and glow discharge was stopped. The valve 2005 is closed to stop the flow of the B ₂ H ₆ / H ₂ gas into the deposition chamber 401.
After continuously flowing the H ₂ gas into the deposition chamber 401 for minutes, the valve 2003 was closed, and the inside of the deposition chamber 401 and the inside of the gas pipe were evacuated.

Next, the A layer is formed on the B layer by the same method, conditions, and procedure as the above method, and the B layer and the A layer are further laminated.
The formation of the second p-type layer having a thickness of about 10 nm was completed. After flowing the H ₂ gas into the deposition chamber 401 continuously, the valve 2003
Was closed, the inside of the deposition chamber 401 and the inside of the gas pipe were evacuated, the auxiliary valve 408 was closed, and the leak valve 409 was opened to leak the deposition chamber 401.

[0373] Next, on the second p-type layer, a transparent electrode, the thickness 70 nm ITO with _{(In 2 O 2 + S nO} 2) was vacuum deposited in a conventional vacuum deposition method. Then, a collector electrode layer thickness 5μm composed of silver (Ag) on the transparent electrode was vacuum deposited by conventional vacuum deposition method. Next , a 3 μm-thick back electrode made of an Ag—Ti alloy was vacuum-deposited on the back surface of the substrate by a normal vacuum deposition method.

Thus, the production of this solar cell was completed. This solar cell is referred to as (SC Ex. 49). Table 17 shows the manufacturing conditions for the first p-type layer, the n-type layer, the Si layer, the i-type layer, and the second p-type layer. (Comparative Example 49-1) The same conditions as in Example 49 except that the SiH ₄ gas flow rate and the CH ₄ gas flow rate were adjusted by the respective mass flow controllers according to the flow rate patterns shown in FIG. 6 when forming the i-type layer. A solar cell was manufactured in the same procedure. This solar cell is referred to as (SC ratio 49-1).

(Comparative Example 49-2) A solar cell was fabricated on a substrate in the same manner and in the same manner as in Example 49 except that no PH ₃ / H ₂ gas was allowed to flow when forming the i-type layer. This solar cell is referred to as (SC ratio 49-2). (Comparative Example 49-3) When forming an i-type layer, B ₂ H ₆ / H
_A solar cell was fabricated on a substrate by the same method and procedure as in Example 49 except that no _two gases were passed. This solar cell (SC
Ratio 49-3).

(Comparative Example 49-4) A solar cell was fabricated under the same conditions and in the same procedure as in Example 49, except that the μW power was changed to 0.5 W / cm ³ when forming the i-type layer. This solar cell is referred to as (SC ratio 49-4). (Comparative Example 49-5) A solar cell was manufactured under the same conditions and in the same procedure as in Example 49, except that the RF power was changed to 0.15 W / cm ³ when forming the i-type layer. This solar cell is referred to as (SC ratio 49-5).

(Comparative Example 49-6) In forming the i-type layer, μW power was 0.5 W / cm ³ and RF power was 0.55.
A solar cell was manufactured under the same conditions and in the same procedure as in Example 49 except that the value was changed to W / cm ³ . This solar cell (SC ratio 4
9-6). (Comparative Example 49-7) A solar cell was fabricated under the same conditions and in the same procedure as in Example 49 except that the pressure in the deposition chamber was set to 0.08 Torr when forming the i-type layer. This solar cell is referred to as (SC ratio 49-7).

(Comparative Example 49-8) Example 4 was repeated except that the deposition rate was 3 nm / sec when forming the Si layer.
A solar cell was fabricated under the same conditions and under the same procedure as in No. 9. This solar cell is referred to as (SC ratio 49-8). (Comparative Example 49-9) When forming the Si layer, the layer thickness was set to 40.
A solar cell was produced under the same conditions and in the same procedure as in Example 49 except that the thickness was changed to nm. This solar cell (SC ratio 49-
9).

The measurement of the initial light conversion efficiency (photovoltaic power / incident light power) and the durability characteristics of the manufactured solar cells (SC Ex. 49) and (SC Comp. 49-1) to (SC Comp. Performed in the same manner as 1. As a result of the measurement, (SC actual 4
For the solar cell of 9), (SC ratio 49-1) to (SC ratio)
The ratio was lower than the initial photoelectric conversion efficiency of the ratio 49-9).

(SC ratio 49-1) 0.75 times (SC ratio 49-2) 0.74 times (SC ratio 49-3) 0.73 times (SC ratio 49-4) 0.66 times (SC ratio) 49-5) 0.82 times (SC ratio 49-6) 0.61 times (SC ratio 49-7) 0.69 times (SC ratio 49-8) 0.70 times (SC ratio 49-9) 82 times The durability characteristics were measured in the same manner as in Example 1. As a result of the measurement, the (SC ratio 49)
-1) to (SC ratio 49-9) were as follows.

(SC ratio 49-1) 0.73 times (SC ratio 49-2) 0.72 times (SC ratio 49-3) 0.71 times (SC ratio 49-4) 0.64 times (SC ratio) 49-5) 0.80 times (49-6 SC ratio) 0.61 times (49-7 SC ratio) 0.71 times (49-8 SC ratio) 0.70 times (49-9 SC ratio) Next, the relationship between the band gap of the i-type layer and the C / Si composition was examined in the same manner as in Example 1. The result was the same as that in FIG.

Also, the manufactured solar cell (SC Ex 49),
The composition analysis in the layer thickness direction of Si atoms and C atoms in the i-type layer of (SC ratio 49-1) to (SC ratio 49-9) is performed by the same method as the above-described composition analysis, and the Si atom and carbon atom are analyzed. When the band gap in the layer thickness direction of the i-type layer was determined from the composition ratio, the same tendency as in FIG. 8 was obtained, and the solar cells of (SC actual 49) and (SC ratio 49-2) to (SC ratio 49-9) were obtained. In this case, the position of the minimum value of the band gap is p
/ I is deviated in the interface direction, and in the solar cell of (SC ratio 49-1), the position of the minimum value of the band gap is deviated in the i / Si interface direction from the center position of the i-type layer. .

As described above, (SC actual 49), (SC ratio 49−
The changes in the band gap in the layer thickness direction of 1) to (SC ratio 49-9) are caused by the source gas containing Si (in this case, SiH ₄ gas) and the source gas containing C (in this case, flowing into the deposition chamber). In some cases, it depends on the flow rate ratio of CH ₄ gas). Next, (SC actual 49), (SC ratio 49-1)
To (SC ratio 49-9) in the layer thickness direction of P atoms and B atoms in the i-type layer by a secondary ion mass spectrometer (CA).
(IMS IMS-3F). As a result of the measurement, it was confirmed that P atoms and B atoms were uniformly distributed in the layer thickness direction.

Also, in the same manner as in Example 33, a polycrystalline silicon
Form a second p-type layer having a laminated structure on a control board
Then, the TEM (transmission electron microscope) image was observed. No.
The p-type layer 2 has a B layer with a thickness of about 1 nm and an A layer with a thickness of about 3 nm
Were alternately laminated. (Comparative Example 49-10) μ introduced when forming i-type layer
W power and RF power are variously changed, and other conditions are examples.
In the same manner as in 49, several solar cells were produced. μW electricity
The force and the deposition rate have the same relationship as in FIG.
ΜW power is 0.32 W / cm, independent of F power^Threethat's all
In this case, the electric power is constant_FourWith gas
CH_FourIt was found that the gas was 100% decomposed.
AM1.5 (100 mW / cm ^Two) When light is irradiated
When the initial photoelectric conversion efficiency of the solar cell was measured, FIG.
The result showed the same tendency as. That is, the μW power is S
iH_FourGas and CH_FourΜW electricity to decompose 100% of gas
Force (0.32W / cm^Three) And RF power is μW
Greater initial photoelectric conversion efficiency when power is higher
I understood that.

(Comparative Example 49-11) In forming the i-type layer in Example 49, the flow rate of the gas introduced into the deposition chamber 401 was set to S.
Some solar cells were fabricated by changing the iH ₄ gas to 50 sccm and the CH ₄ gas to 10 sccm, not introducing the H ₂ gas, and varying the μW power and the RF power. Other conditions were the same as in Example 49. When the relationship between the deposition rate and the μW power and the RF power was examined, the deposition rate did not depend on the RF power and the μW power was 0.18 W / c as in Comparative Example 49-10.
It was found that the SiH ₄ gas and the CH ₄ gas, which are the source gases, were decomposed 100% with this μW power at a constant value of m ³ or more. When the initial photoelectric conversion efficiency of the solar cell when irradiating AM1.5 light was measured, the result showed the same tendency as FIG. That is, the μW power is S
μW for decomposing 100% of iH ₄ gas and CH ₄ gas
Power (0.18 W / cm ³ ) or less and RF power is μ
It was found that the initial photoelectric conversion efficiency was significantly improved when the power was larger than the W power.

(Comparative Example 49-12) In forming the i-type layer in Example 49, the flow rate of the gas introduced into the deposition chamber 401 was set to S.
iH ₄ gas 200 sccm, CH ₄ gas 50 sccm,
H ₂ gas was changed to 500 sccm and the substrate temperature was 3
Change the heater setting so that the temperature becomes
Several solar cells were fabricated with various power and RF powers. Other conditions were the same as in Example 49.

When the relationship between the deposition rate and the μW power and the RF power was examined, the deposition rate was R as in Comparative Example 49-10.
Without depending on F power, at constant μW power 0.65 W / cm ³ or more, SiH ₄ Gas good <br/> beauty CH ₄ gas as a source gas in this power that has been decomposed 100% Do you get it. When the initial photoelectric conversion efficiency of the solar cell when irradiating AM1.5 light was measured, the result showed the same tendency as in FIG. That is, the μW power is SiH ₄ gas and
ΜW power for decomposing 100% of CH ₄ gas (0.65W /
cm ³ ) or less and the RF power was larger than the μW power, it was found that the initial photoelectric conversion efficiency was greatly improved.

(Comparative Example 49-13) In forming the i-type layer in Example 49, the pressure in the deposition chamber was increased from 3 mTorr to 20
Various conditions were changed up to 0 mTorr, and other conditions were the same as in Example 49.
Some solar cells were produced in the same manner as described above. AM1.5
When the initial photoelectric conversion efficiency of the solar cell when irradiating light was measured, the result was as shown in FIG.
It was found that the initial photoelectric conversion efficiency was greatly reduced at Torr or higher.

(Comparative Example 49-14) In forming the Si layer in Example 49, the deposition rate was variously changed by changing the SiH ₄ gas flow rate and the RF power, and the other conditions were the same as in Example 49. Some solar cells were produced. AM
When the initial photoelectric conversion efficiency of the solar cell when irradiating 1.5 light was measured, the deposition rate of the Si layer was 2 nm / sec.
From the above, it was found that the initial photoelectric conversion efficiency was greatly reduced.

(Comparative Examples 49-15) In forming an Si layer in Example 49, several solar cells were produced by changing the layer thickness variously and using the other conditions as in Example 49. AM1.
Measurement of the initial photoelectric conversion efficiency of the solar cell when five light beams were irradiated showed that the initial photoelectric conversion efficiency was greatly reduced when the layer thickness was 30 nm or more.

As described above, (Comparative Example 49-1) to (Comparative Example 49-1)
-15), the solar cell (SC actual 49) of the present invention is different from the conventional solar cells (SC ratio 49-1) to (SC
Ratio 49-9). (Example 50) position relative to the layer thickness direction of the minimum band gap (Eg) in Example 49, the magnitude of the minimum value, to produce several solar cells with different 及 beauty pattern, its initial photoelectric conversion efficiency 及 And durability characteristics were examined in the same manner as in Example 49.
At this time, other than the change pattern of the SiH ₄ gas flow rate and CH ₄ gas flow rate of the i-type layer was prepared the same west solar cell that have a band gap shown in FIG. 12 and Example 49.

The results obtained by examining the initial photoelectric conversion efficiency and durability characteristics of these manufactured solar cells are shown in Table 18 (the values in the table are based on SC Example (50-1)). As can be seen from these results, the magnitude of the minimum value of the band gap,
Regardless of the change pattern, the band gap of the i-type layer changes smoothly in the layer thickness direction, and the position of the minimum value of the band gap is shifted from the center position of the i-type layer toward the p / i interface. It turns out that solar cells are better.

(Example 51) In Example 49, a solar cell was produced in which the concentration and type of the valence electron controlling agent in the i-type layer were changed, and the initial photoelectric conversion characteristics and durability were determined in the same manner as in Example 1. I checked in. At this time, it was the same as Example 49 except that the concentration and type of the valence electron controlling agent in the i-type layer were changed.

(Example 51-1) The flow rate of the gas (B ₂ H ₆ / H ₂ gas) of the valence electron controlling agent serving as the acceptor of the i-type layer was reduced to 1/5, and the total H ₂ flow rate was changed to that of Example 49. When a solar cell (SC Ex. 51-1) having the same structure as that described above was manufactured,
Like (SC Ex. 49), (SC Ex. 51-1) has better initial photoelectric conversion efficiency and durability than conventional solar cells (SC Comp. 49-1) to (SC Comp. I understood.

(Example 51-2) The flow rate of the gas (B ₂ H ₆ / H ₂ gas) of the valence electron controlling agent serving as the acceptor of the i-type layer was increased by 5 times, and the total H ₂ flow rate was the same as in Example 49. When a solar cell (SC Ex 51-2) was manufactured,
Similar to (SC Ex. 49), C Ex. 51-2) may have better initial photoelectric conversion efficiency and durability than conventional solar cells (SC Comp. 49-1) to (SC Comp. Do you get it.

(Example 51-3) The flow rate of the gas (PH ₃ / H ₂ gas) of the valence electron controlling agent serving as the donor of the i-type layer was reduced to 1/5, and the total H ₂ flow rate was the same as in Example 49. (SC Ex. 51-3) was manufactured, and as in (SC Ex. 49), the conventional solar cells (SC Comp. 49-1) to (SC Comp. ) Was found to have even better initial photoelectric conversion efficiency and durability characteristics.

(Example 51-4) The flow rate of the gas (PH ₃ / H ₂ gas) of the valence electron controlling agent serving as the donor of the i-type layer was made five times, and the total H ₂ flow rate was made the same as in Example 49. When a solar cell (SC Ex. 51-3) was manufactured, (SC Ex. 5)
1-4) is a conventional solar cell (S
It was found to have better initial photoelectric conversion efficiency and durability than C ratio 49-1) to (SC ratio 49-9).

(Example 51-5) Instead of B ₂ H ₆ / H ₂ gas, trimethyl aluminum (Al (CH ₃ ) ₃ , TM) was used as the valence electron controlling agent gas serving as the acceptor of the i-type layer.
A solar cell using A) was produced. At this time, except that TMA (purity: 99.99%) sealed in a liquid cylinder was gasified by bubbling with hydrogen gas and introduced into the deposition chamber 401, a solar cell (SC actual) was manufactured in the same manner and procedure as in Example 49. 5
1-5) was produced.

At this time, the flow rate of the TMA / H ₂ gas was 10 seconds.
ccm. The manufactured solar cell (SC Ex. 51-5) is similar to the conventional solar cell (SC Comp.
1) It was found to have better initial photoelectric conversion efficiency and durability than (SC ratio 49-9). (Example 51-6) Hydrogen sulfide (H ₂₎ was used instead of PH ₃ / H ₂ gas as a valence electron controlling gas serving as a donor of the i-type layer.
A solar cell using S) was produced. NH _{3 of} Example 49
/ H ₂ gas cylinder diluted with hydrogen to 100 ppm H ₂ S
The gas (H ₂ S / H ₂ ) was replaced with a gas cylinder, and a solar cell (SC Ex. 51-6) was produced in the same manner and procedure as in Example 49.

At this time, the flow rate of the H ₂ S / H ₂ gas is 1 scc.
m. The manufactured solar cell (SC Ex. 51-6) is (S
Similar to the conventional solar cell 49), the conventional solar cell (SC ratio 49-1)
It was found to have better initial photoelectric conversion efficiency and endurance characteristics than (SC ratio 49-9). (Example 52) A solar cell shown in FIG. 1-b was fabricated using a p-type polycrystalline silicon substrate. Performing a plasma treatment on the substrate, followed by a first n-type layer, a p-type layer, an i-type layer,
An i-layer and a second n-type layer were sequentially formed. Table 19 shows the forming conditions. When forming the i-type layer, the flow rate of SiH ₄ gas and CH
_{4 The} gas flow rate was changed as shown in the pattern of FIG.
The minimum value of the band gap was set to be higher than the interface.
The second n-type layer had a laminated structure as in Example 49, and the deposition rate of the Si layer was 0.15 nm / sec. Substrates and layers other than the semiconductor layer were the same as in Example 49,
Fabricated using the same method.

The manufactured solar cell (SC Ex. 52) is (SC
As in the case of the actual solar cell 49), the conventional solar cell (SC ratio 49-1)-
It was found to have better initial photoelectric conversion efficiency and durability than (SC ratio 49-9). (Example 53) A solar cell having a maximum value of the band gap of the i-type layer in the vicinity of the p / i interface and having a thickness of 20 nm in the region is used as the flow rate change pattern of the i-type layer shown in FIG. It produced using it.

[0402] A film was fabricated using the same conditions and the same method as in Example 49 except that the flow rate change pattern of the i-type layer was changed. Next, the composition of the solar cell was analyzed in the same manner as in Example 49, and the change in band gap in the thickness direction of the i-type layer was examined. The result was the same as that in FIG. 13-b. The manufactured solar cell (SC Ex. 53) has better initial photoelectric conversion efficiency and durability than the conventional solar cells (SC Comp. 49-1) to (SC Comp. It was found to have.

(Comparative Example 53) There was a region having the maximum value of the band gap near the p / i interface of the i-type layer, and several solar cells were manufactured in which the thickness of the region was variously changed. Except for the thickness of the region, it was manufactured using the same conditions and the same method as in Example 53. When the initial photoelectric conversion efficiency and durability of the manufactured solar cell were measured, the thickness of the region was 1 nm.
Above 30 nm or less, the solar cell (SC
As a result, better initial photoelectric conversion efficiency and durability were obtained than in the case of Example 49).

(Example 54) There is a maximum value of the band gap of the i-type layer near the i / Si interface, and the thickness of the region is 1
A solar cell having a thickness of 5 nm was manufactured using the flow rate change pattern of the i-type layer shown in FIG. Except for changing the flow rate change pattern of the i-type layer, it was manufactured using the same conditions and the same method as in Example 49. Next, composition analysis of a solar cell was performed in Example 4.
When the change in band gap in the thickness direction of the i-type layer was examined in the same manner as in FIG. 9, the same result as in FIG. 13-d was obtained. The manufactured solar cell (SC Ex. 54) is (SC Ex. 4)
9), conventional solar cells (SC ratio 49-1) to (S
It was found to have better initial photoelectric conversion efficiency and durability than C ratio 49-9).

(Comparative Example 54) There was a region having the maximum value of the band gap near the i / Si interface of the i-type layer, and several solar cells were manufactured with various thicknesses of the region. Except for the thickness of the region, it was manufactured using the same conditions and the same method as in Example 54. When the initial photoelectric conversion efficiency and durability of the manufactured solar cell were measured, the thickness of the region was 1 nm.
As described above, when the thickness is 30 nm or less, even better initial photoelectric conversion efficiency and durability than the solar cell of Example 49 (SC Ex. 49) were obtained.

(Example 55) A solar cell in which a valence electron controlling agent is distributed in an i-type layer was subjected to PH ₃ / H ₂ shown in FIG.
It was produced using a change pattern of the gas and the flow rate of the B ₂ H ₆ / H ₂ gas. At the time of fabrication, the same conditions, the same method, and procedure as in Example 49 were used, except that the flow rates of PH ₃ / H ₂ gas and B ₂ H ₆ / H ₂ gas were changed. The fabricated solar cell (SC actual 23)
Is a conventional solar cell (SC ratio 49
-1) to (SC ratio 49-9) were found to have better initial photoelectric conversion efficiency and durability. Further, when the change in the layer thickness direction of the P atoms and the B atoms contained in the i-type layer was examined by using a secondary ion mass spectrometer (SIMS), the result was similar to that of FIG. It was found that the content of P and B atoms was minimum at the minimum position.

Example 56 A solar cell having an i-type layer containing oxygen atoms was manufactured. In forming the i-type layer, O ₂ / He gas is supplied at 10 sc in addition to the gas flowing in Example 49.
cm, the same conditions, the same method, and the same procedure as in Example 49 were used, except that the sample was introduced into the deposition chamber 401. The manufactured solar cell (SC Ex. 56) has better initial photoelectric conversion efficiency and durability than the conventional solar cells (SC Comp. 49-1) to (SC Comp. 49-9), similarly to (SC Ex. 49). It was found to have.

The content of oxygen atoms in the i-type layer was determined by SI
As a result of examination by MS, it was contained almost uniformly, and 2 × 10 ¹⁹
(Pieces / cm ² ). Example 57 A silicon solar cell having an i-type layer containing nitrogen atoms was manufactured. When forming the i-type layer, NH ₃ / H ₂ gas is supplied at 5 scc in addition to the gas flowing in Example 49.
m, the same conditions, the same method, and the same procedure as in Example 49 were used, except that they were introduced into the deposition chamber 401. The manufactured solar cell (SC Ex. 57) exhibits better initial photoelectric conversion efficiency and durability than the conventional solar cells (SC Comp. 49-1) to (SC Comp. 49-9), similarly to (SC Ex. 49). It was found to have. Further, the content of nitrogen atoms in the i-type layer is determined by SI
As a result of examination by MS, it was contained almost uniformly, and 3 × 10 ¹⁷
(Pieces / cm ² ).

(Example 58) An oxygen atom and a nitrogen atom were added to the i-type layer.
A solar cell containing elemental atoms was produced. i-type layer
When forming, in addition to the gas flowing in Example 49, O_Two/ He
5 sccm gas, NH_Two/ H_Two5 sccm of gas
The same conditions as in Example 49 except that they are introduced into the storage chamber 401,
The same method and the same procedure were used. The fabricated solar cell (SC
Actual 58) is the same as (SC Ex 49) in the conventional solar cell (S
Even better than C ratio 49-1) to (SC ratio 49-9)
Have high initial photoelectric conversion efficiency and durability
Was. Also, the content of oxygen atoms and nitrogen atoms in the i-type layer
When examined by SIMS, it was found to be almost uniformly contained.
1 × 10¹⁹(Pcs / cm^Two), 3 × 10¹⁷(Pcs / cm
^Two).

(Example 59) A solar cell was manufactured in which the hydrogen content of the i-type layer was changed in accordance with the silicon content. The O ₂ / He gas cylinder was filled with SiF ₄ gas (purity 99.
When the i-type layer is formed by replacing the cylinder with a cylinder, FIG.
According to the flow pattern of 5-a, SiH ₄ gas, CH ₄
The flow rates of the gas and the SiF ₄ gas were changed. The change in band gap in the layer thickness direction of this solar cell (SC Ex 59) was determined by the same method as in Example 49. FIG.
The same result as was obtained.

Further, the content of hydrogen atoms and silicon atoms was analyzed in the layer thickness direction using a secondary ion mass spectrometer. It was found that the hydrogen atom content had a distribution in the layer thickness direction corresponding to the silicon atom content. When the initial photoelectric conversion efficiency and durability characteristics of this solar cell (SC Ex. 59) were determined, similar to the solar cell of Example 49, the results were obtained from the conventional solar cells (SC ratio 49-1) to (SC ratio 49-9). Was found to have better initial photoelectric conversion efficiency and durability.

Example 60 When a semiconductor layer of the solar cell shown in FIG. 1 was formed by the manufacturing apparatus using the microwave plasma CVD method shown in FIG.
Example 49 except that H ₄ gas) and a carbon atom-containing gas (CH ₄ gas) were mixed at a distance of 1 m from the deposition chamber.
A solar cell (SC Ex. 60) was produced in the same manner and in the same procedure as described above. The manufactured solar cell (SC actual 60) is (SC actual 4)
It was found to have better initial photoelectric conversion efficiency and durability than 9).

Example 61 A first p-type layer was formed by a gas diffusion method, and when forming an i-type layer, a C ₂ H ₂ gas was used instead of a CH ₄ gas, and a positive DC A solar cell was manufactured by applying a bias and changing RF power, DC bias, and μW power. First, BBr ₃ (BBr ₃ / H ₂ gas) obtained by diluting an O ₂ / He gas cylinder to 10% with hydrogen.
The cylinder was replaced with a cylinder, and the CH ₄ gas cylinder was further replaced with a C ₂ H ₂ gas.

When forming the first p-type layer, a substrate temperature of 90
0 ° C., BBr ₃ / H ₂ gas flow rate 500 sccm, internal pressure 3
Under the condition of 0 Torr, B was diffused into the n-type substrate. When the junction depth reached 300 nm, the introduction of BBr ₃ / H ₂ gas was stopped. H ₂ gas was kept flowing for 5 minutes. Also i
In forming the mold layer, C ₂ H ₂ gas was introduced instead of CH ₄ gas, and the flow rate was changed according to the flow pattern as shown in FIG. Further, as shown in FIG. 16, the RF power, the DC bias, and the μW power were changed. Except for the first p-type layer and the i-type layer, the same conditions, the same method, and the same procedure as in Example 49 were used. The manufactured solar cell (SC Ex 61) is (SC Ex 49)
Similarly to the above, it was found that the solar cell had better initial photoelectric conversion efficiency and durability than conventional solar cells (SC ratio 49-1) to (SC ratio 49-9).

(Example 62) [0415] Using the manufacturing apparatus of FIG. 4 using the microwave plasma CVD method of the present invention, FIG.
Was manufactured. The substrate was manufactured in Example 49.
An n-type polycrystalline silicon substrate manufactured by the casting method was used in the same manner as in the above.

One side of a 50 × 50 mm ² substrate was heated at a temperature of 10
It was immersed in a 1% NaOH aqueous solution at 0 ° C. for 5 minutes, and washed with pure water. Scan the surface immersed in NaOH with a scanning electron microscope (SE
Observed in (M), irregularities having a pyramid structure were formed on the surface, and the substrate was textured (Te
xtured). Next, the substrate was ultrasonically washed with acetone and isopropanol, further washed with pure water, and dried with warm air.

Water was prepared in the same procedure and in the same manner as in Example 49.
Elementary plasma treatment and the first surface on the textured surface of the substrate
And a first n-type layer, a first i-type layer
Layer, second p-type layer, second n-type layer, Si layer, second i-type
A layer and a third p-type layer were sequentially formed. Form a second i-type layer
At the time, the SiH
_FourGas flow, CH_FourChange the gas flow rate to deposit the Si layer
The speed was 0.15 nm / sec. Furthermore, the third p-type
The layer had a laminated structure as in Example 49.

Next, as in Example 49, a 70 nm-thick ITO (In ₂ O) layer was formed on the third p-type layer as a transparent electrode.
₃ + SnO ₂ ) was vacuum-deposited by a normal vacuum deposition method. Next, as in Example 49, a 5 μm-thick current collecting electrode made of silver (Ag) was vacuum-deposited on the transparent electrode by a normal vacuum deposition method. Next, as in Example 49, the Ag-T
A 3 μm-thick back electrode made of an i-alloy was vacuum-deposited by a normal vacuum deposition method.

[0419] Thus, the fabrication of the triple solar cell using the microwave plasma CVD method is completed. This solar cell is referred to as (SC Ex. 62). Table 20 shows the manufacturing conditions of each semiconductor layer. (Comparative Example 62-1) A method similar to that of Example 62 except that the SiH ₄ gas flow rate and the CH ₄ gas flow rate were changed according to the flow rate change pattern in FIG. 6 when forming the second i-type layer in FIG. A triple solar cell was manufactured in the same procedure. This solar cell will be referred to as (SC Comp. 62-1).

(Comparative Example 62-2) When forming the second i-type layer in FIG. 17, except that no PH ₃ / H ₂ gas was flowed, a solar cell was formed on the substrate by the same method and procedure as in Example 62. A battery was manufactured. This solar cell will be referred to as (SC Comp. 62-2). In forming the second i-type layer (Comparative Example 62-3) 17, the same method as in Example 62 except that no shed B ₂ H ₆ / H ₂ gas, solar cell on a substrate in step Was prepared. This solar cell is referred to as (SC ratio 62-3).

(Comparative Example 62-4) When forming the second i-type layer in FIG. 17, a triple method was performed in the same manner and in the same procedure as in Example 62 except that the μW power was changed to 0.5 W / cm ^3. A solar cell was fabricated. This solar cell (SC ratio 62-4)
I will call it. (Comparative Example 62-5) When forming the second i-type layer in FIG. 17, a triple type solar cell was manufactured in the same manner and in the same procedure as in Example 62 except that the RF power was changed to 0.15 W / cm ^3. Was prepared. This solar cell will be referred to as (SC Comp. 62-5).

[0422] (Comparative Example 62-6) when forming the second i-type layer in FIG. 17, except that the μW power 0.5 W / cm ^3, the RF power to 0.55 W / cm ³ Example 62 A triple-type solar cell was produced in the same manner and in the same procedure. This solar cell is referred to as (SC ratio 62-6).

(Comparative Example 62-7) When forming the second i-type layer in FIG. 17, the pressure in the deposition chamber 401 was set to 0.08 Torr.
A triple-type solar cell was produced in the same manner and in the same procedure as in Example 62 except for the following. This solar cell is referred to as (SC ratio 62-7). (Comparative Example 62-8) A triple type solar cell was manufactured in the same manner as in Example 62, except that the deposition rate was 3 nm / sec when forming the Si layer in FIG. This solar cell is referred to as (SC ratio 62-8).

(Comparative Example 62-9) A triple solar cell was manufactured in the same manner as in Example 62, except that the thickness of the Si layer in FIG. 17 was changed to 40 nm, and the procedure was similar to that of Example 62.
This solar cell is referred to as (SC ratio 62-9).
The initial photoelectric conversion efficiency and durability characteristics of these fabricated triple solar cells were measured by the same method as in Example 49, and (SC Ex. 62) showed that the conventional triple solar cell (SC
It was found to have better initial photoelectric conversion efficiency and durability than the ratios 62-1) to (SC ratio 62-9).

(Example 63) The solar cell of Example 49 was manufactured using the manufacturing apparatus of FIG. 4 using the microwave plasma CVD method of the present invention, modularized, and applied to a power generation system. A 50 × 50 mm ² solar cell (SC Ex 49) was prepared under the same conditions, the same method, and the same procedure as in Example 49.
Five were produced. E on a 5.0 mm thick aluminum plate
An adhesive sheet made of VA (ethylene vinyl acetate) was placed thereon, a nylon sheet was placed thereon, and the solar cells produced were further arranged thereon to perform serialization and parallelization. An EVA adhesive sheet was placed thereon, and a fluororesin sheet was further placed thereon, and vacuum-laminated to form a module. The initial photoelectric conversion efficiency of the manufactured module was measured in the same manner as in Example 49.
The module was connected to the circuit showing the power generation system of FIG. 18, and an external light that was lit at night was used for the load. The entire system was powered by the battery and the power of the module, and the module was installed at an angle that could best collect sunlight. 1
The photoelectric conversion efficiency after a lapse of one year was measured, and the light deterioration rate (photoelectric conversion efficiency after one year / initial photoelectric conversion efficiency) was obtained. This module is called (MJ 63).

Comparative Example 63-1 A conventional solar cell (SC)
Ratio 49-X) (X: 1 to 9) were manufactured under the same conditions, under the same method, and under the same conditions as those of Comparative Example 49-X, and were modularized as in Example 63. This module (MJ ratio 6
3-X). The initial photoelectric conversion efficiency and the photoelectric conversion efficiency after one year had elapsed were measured under the same conditions, the same method, and the same procedure as in Example 63, and the light deterioration rate was obtained.

As a result, the light degradation rate of (MJ ratio 63-X) was as follows with respect to (MJ actual 63). Module Light Degradation Ratio 実 MJ Actual 63 1.00 MJ Ratio 63-1 0.72 MJ Ratio 63-2 0.71 MJ ratio 63-3 0.70 MJ ratio 63-4 0.68 MJ ratio 63-5 0.75 MJ ratio 63-6 0.65 MJ ratio 63-7 0.72 MJ ratio 63-8 0.0. From the results of 70 MJ ratio 63-9 0.82 and above, it was found that the solar cell module of the present invention had more excellent light degradation characteristics than the conventional solar cell module.

(Example 64) Microwave plasm of the present invention
Using the manufacturing apparatus shown in FIG.
The solar cell of FIG. 19 having the second Si layer at the interface was fabricated.
Was. Manufactured by the casting method as in Example 49.
Built 50 × 50mm ^TwoN-type polycrystalline silicon substrate
HF and HNO_Three(H_TwoAqueous solution (diluted to 10% with O)
For several seconds and washed with pure water. Then acetone and isop
Ultrasonic cleaning with lopanol, further cleaning with pure water, warm air
Let dry.

A hydrogen plasma treatment is performed by the same procedure and in the same manner as in Example 49 to form a first p-type layer on the substrate, and further a first n-type layer, a first Si layer, and an i-type Layer, second
, And a second p-type layer were sequentially formed. When forming the i-type layer, the SiH
₄ gas flow rate and CH ₄ gas flow rate
Layer, the deposition rate of the second Si layer is 0.15 nm / sec,
The layer thickness was 10 nm. Further, the second p-type layer was formed in Example 4.
The laminated structure was the same as that of No. 9.

Next, on the second p-type layer, a 70 nm-thick ITO (In) layer was formed as a transparent electrode in the same manner as in Example 49.
₂ O ₃ + SnO ₂ ) was vacuum deposited by a normal vacuum deposition method. Next, silver (Ag) was formed on the transparent electrode in the same manner as in Example 49.
A 5 μm-thick current collecting electrode made of was vacuum-deposited by an ordinary vacuum deposition method. Next, as in Example 49, A
A back electrode made of a g-Ti alloy and having a thickness of 3 μm was vacuum-deposited by a normal vacuum deposition method.

[0431] This solar cell is referred to as (SC Ex. 64). Table 21 shows the manufacturing conditions of each semiconductor layer. When the initial photoelectric conversion efficiency and the durability characteristics of the manufactured solar cell were measured by the same method as in Example 49, (SC Ex 64) was (SC Ex.
As in the case of the actual solar cell 49), the conventional solar cell (SC ratio 49-1)-
It was found to have better initial photoelectric conversion efficiency and durability than (SC ratio 49-9).

As described above, it has been proved that the effects of the photovoltaic device of the present invention can be exhibited irrespective of the device configuration, device material, and device manufacturing conditions.

[0433]

[Table 7]

[0434]

[Table 2]

[0435]

[Table 3]

[0436]

[Table 4]

[0437]

[Table 5]

[0438]

[Table 6]

[0439]

[Table 7]

[0440]

[Table 8]

[0441]

[Table 9]

[0442]

[Table 10]

[0443]

[Table 11]

[0444]

[Table 12]

[0445]

[Table 13]

[0446]

[Table 14]

[0447]

[Table 15]

[0448]

[Table 16]

[0449]

[Table 17]

[0450]

[Table 18]

[0451]

[Table 19]

[0452]

[Table 20]

[0453]

[Table 21]

[0454]

As described above, the photovoltaic device of the present invention prevents recombination of photoexcited carriers, improves the open voltage and the carrier range of holes, and improves the sensitivity to short wavelength light and long wavelength light. It is possible to provide a photovoltaic power having improved photoelectric conversion efficiency. Further, the photovoltaic element of the present invention can suppress a decrease in photoelectric conversion efficiency that occurs when light is irradiated for a long time. The photovoltaic device of the present invention is one in which the photoelectric conversion efficiency does not easily decrease when annealing is performed under vibration for a long time.

Further, the power supply system using the photovoltaic element of the present invention exhibits excellent power supply capability even when the irradiation light is weak.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a layer configuration of a photovoltaic element of the present invention.

FIG. 2 is a diagram showing a band gap of a photovoltaic device of the present invention.

FIG. 3 is a diagram showing a band gap of a photovoltaic device of the present invention.

FIG. 4 is a conceptual diagram showing an example of a photovoltaic device manufacturing apparatus of the present invention.

FIG. 5 is a graph showing SiH ₄ and CH ₄ gas flow rate patterns.

FIG. 6 is a graph showing SiH ₄ and CH ₄ gas flow patterns.

FIG. 7 is a graph showing the relationship between the composition ratio of Si atoms and C atoms and the band gap.

FIG. 8 is a graph showing a change in a band gap in a layer thickness direction.

FIG. 9 is a graph showing the relationship between μW power and deposition rate.

FIG. 10 is a graph showing dependence of initial photoelectric conversion efficiency on μW power and RF power.

FIG. 11 is a graph showing pressure dependence of initial photoelectric conversion efficiency.

FIG. 12 is a diagram showing a change in a band gap in a layer thickness direction.

FIG. 13 is a graph showing a change in a flow rate pattern and a band gap in a layer thickness direction.

FIG. 14 is a graph showing a C ₂ H ₂ flow rate pattern and a change pattern of μW power.

FIG. 15 is a graph showing a band gap and a hydrogen content of an i-type layer in which hydrogen atoms are distributed, and a gas flow pattern when the i-type layer is formed.

FIG. 16 is a graph showing a change pattern of DC bias, RF power, and μW power.

FIG. 17 is a conceptual diagram showing a layer configuration of a triple solar cell.

FIG. 18 is a block diagram showing a power generation system of the present invention.

FIG. 19 is a conceptual diagram showing a photovoltaic device having a second Si layer at a p / i interface.

FIG. 20 shows B ₂ H ₆ / H ₂ and PH ₃ / H ₂ when forming an i-type layer.
4 is a graph showing a gas flow pattern and a distribution of B and P atom contents in an i-type layer in a layer thickness direction.

FIG. 21 is a diagram showing a TEM of a p-layer having a stacked structure.

[Explanation of symbols]

REFERENCE SIGNS LIST 101 back electrode 102 n-type silicon substrate 103 first p-type layer 104 n-type layer 105 Si layer 106 i-type layer 107 second p-type layer 108 transparent electrode 109 collector electrode 121 back electrode 122 p-type silicon substrate 123 first 1 n-type layer 124 p-type layer 125 i-type layer 126 Si layer 127 second n-type layer 128 transparent electrode 129 collecting electrode 211, 221 i-type layer 212, 222 Si layer 311, 321, 331, 341, 351, 351 , 361,3
71 Region where band gap changes 312, 322, 332, 333, 342, 343, 3
52,362,372,373 Band gap constant region 334,344,354,364,374 Si layer 401 Deposition chamber 402 Vacuum gauge 403 RF power supply 404 Substrate 405 Heater 407 Conductance valve 408 Auxiliary valve 409 Leak valve 410 RF electrode 411 Gas introduction tube 412 Microwave waveguide 413 Dielectric window 415 Shutter 2000 Source gas supply device 2001-2007, 2021-2027 Valve 2011-2017 Mass flow controller 2031-2037 Pressure regulator 2041-2047 Source gas cylinder.

Continuation of front page (56) References JP-A-63-22582 (JP, A) JP-A-63-224371 (JP, A) JP-A-59-971 (JP, A) JP-A-3-131072 (JP, A) JP-A-3-208376 (JP, A) JP-A-3-214676 (JP, A) JP-A-64-71181 (JP, A) JP-A-59-124772 (JP, A) (58) Field surveyed (Int.Cl. ⁶ , DB name) H01L 31/04

Claims (17)

(57) [Claims] 1. A first p-type layer made of microcrystalline silicon, polycrystalline silicon, or single-crystal silicon, or a non-single-crystal semiconductor material, on an n-type substrate made of polycrystalline silicon or single-crystal silicon. In a photovoltaic device in which an n-type layer made of a non-single-crystal semiconductor material, an i-type layer made of a non-single-crystal semiconductor material, and a second p-type layer made of a non-single-crystal semiconductor material are sequentially stacked, the i-type layer has at least silicon atoms. and containing carbon atoms, the band gap changes in the thickness direction of the i-type layer,
And a valence electron controlling agent serving as a donor and an acceptor in the i-type layer.
And the content of the valence control agent in the vicinity of the interface between the i-type layer and the p-type layer and / or the n-type layer is higher than that in the i-type layer. A photovoltaic element characterized by having a large number. 2. The method according to claim 1, wherein the i-type layer and the n-type layer made of the non-single-crystal semiconductor material and / or the i- type layer and the second p-type layer are formed.
The photovoltaic element according to claim 1, further comprising a Si layer made of a non-single-crystal material between the photovoltaic element and the mold layer. 3. The main constituent element of at least one of the second p-type layer, the n-type layer, and the first p-type layer is selected from silicon, carbon, oxygen, and nitrogen. A layer (A layer) comprising at least one element and containing a Group III element, a Group V element, or a Group VI element of the periodic table as a valence electron controlling agent; The photovoltaic device according to claim 1, wherein the photovoltaic device has a laminated structure with a layer (B layer) mainly composed of a Group IV element or a Group VI element. 4. A first n-type layer made of microcrystalline silicon, polycrystalline silicon, or single-crystal silicon, or a non-single-crystal semiconductor material, on a p-type substrate made of polycrystalline silicon or single-crystal silicon. In a photovoltaic element in which a p-type layer made of a non-single-crystal semiconductor material and a second n-type layer made of a non-single-crystal semiconductor material are sequentially stacked, the i-type layer has at least silicon atoms. And the carbon atom, the band gap changes in the thickness direction of the i-type layer,
A photovoltaic device wherein the i-type layer is doped with a valence electron controlling agent serving as a donor and a valence electron controlling agent serving as an acceptor, and the content thereof is changed in the i-type layer. 5. A semiconductor device comprising: a p-type layer made of the non-single-crystal semiconductor and the i-type layer; and / or a Si layer made of a non-single-crystal material between the i-type layer and the second n-type layer. The photovoltaic device according to claim 4, wherein: 6. The main constituent element of at least one of the second n-type layer, the p-type layer, and the first n-type layer is selected from silicon, carbon, oxygen, and nitrogen. A layer (A layer) comprising at least one element and containing a Group III element, a Group V element, or a Group VI element of the periodic table as a valence electron controlling agent; The photovoltaic device according to claim 4, wherein the photovoltaic device has a laminated structure with a layer (B layer) mainly composed of a Group IV element or a Group VI element. 7. A least one of the thickness direction of both ends of the i-type layer, there is a region having the maximum band gap of the i-type layer, the thickness of the region is 1~30nm The photovoltaic device according to claim 1 or 4, wherein 8. The valence electron controlling agent serving as the donor is a group III element of the periodic table, and the valence electron controlling agent serving as the acceptor is a group V or VI element of the periodic table. The photovoltaic device according to claim 1 or 4, wherein 9. The photovoltaic device according to claim 1, wherein the valence electron controlling agent is distributed more in places where the carbon content is large and less in places where the carbon content is small. 10. The method according to claim 1, wherein the i-type layer contains oxygen atoms and / or nitrogen atoms.
The photovoltaic device according to any one of the preceding claims. 11. The oxygen atom and / or the nitrogen atom
11. The photovoltaic device according to claim 10, wherein the content increases or decreases according to the content of carbon atoms . 12. The photovoltaic device according to claim 1, wherein the content of hydrogen atoms contained in the i-type layer changes according to the content of silicon atoms. 13. The method according to claim 1, wherein the i-type layer is formed by a microwave plasma CVD method at an internal pressure of 50 mTorr or less.
The magnitude of the applied microwave energy is lower than the microwave energy for decomposing the raw material gas by 100%, and the RF energy is applied, and the magnitude of the RF energy is higher than the microwave energy. Item 2. The photovoltaic element according to Item 1. 14. The photovoltaic device according to claim 2, wherein the Si layer contains a Group V element and / or a Group VI element of the periodic table. 15. The light according to claim 2, wherein the Si layer contains both a Group III element of the periodic table and a Group V element and / or a Group VI element of the Periodic Table. Electromotive element. 16. The photovoltaic device according to claim 2, wherein the Si layer is formed by an RF plasma CVD method, and has a deposition rate of 2 nm / sec or less and a layer thickness of 30 nm or less. 17. A photovoltaic element according to claim 1, further comprising: a storage battery for storing power supplied from the photovoltaic element and supplying power to an external load. A power generation system comprising a control system for monitoring voltage and / or current of a photovoltaic element and controlling power supplied from the photovoltaic element to the storage battery and / or the external load.