JPH0621490A - Photovoltaic element, manufacture thereof and power generator system using the same - Google Patents

Abstract

PURPOSE:To prevent recombination of photovoltaic carriers, to improve open voltage and carrier range of holes, and to improve the conversion efficiency when irradiating light is weak. CONSTITUTION:A p-type layer 105 formed of a silicon series non-single crystalline semiconductor material, a photoconductive layer (a layer formed of a plurality of i-type layers) and an n-type layer 102 are at least formed in multilayer. The photoconductive layer is formed of a multilayer structure having at least an i-type layer 104 deposited by a microwave plasma CVD method on the side of the layer 105, and an i-type layer 103 deposited by an RF plasma CVD method on the side of the layer 102. The layer 104 disposed by the microwave plasma CVD method contains at least silicon atoms and carbon atoms in such a manner that a position where the band gap is a minimum is at the i-type layer formed to be deviated toward a p-type layer from the center of the i-type layer. And, the layer 103 deposited by the RF plasma CVD method contains at least silicon atoms and has a thickness of 30nm or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pin type photovoltaic element made of a silicon-based non-single-crystal semiconductor material, a method of manufacturing the same, and a power generation system using the same. In particular, the present invention relates to a pin-type photovoltaic element in which the bandgap in the i-type layer is changed, and further relates to a deposition method of the photovoltaic element by microwave plasma CVD. In addition, it relates to a power generation system using the photovoltaic element.

[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, the i layer contains a silicon atom and a germanium atom or a carbon atom,
Various proposals have been made as described below for a photovoltaic device in which the band gap is changed in the i-type layer. For example, (1) "Optimum deposit
ion conditions for a- (Si,
Ge): Housing a triode-conf
igurated rf glow discharg
e system ”, JA Braggnolo,
P. Littlefield, A .; Mastrovit
o and G. Storeti, Conf. Rec. 1
9th IEEE Photovoltaic spe
cilists Conference-1987, p.
p. 878, (2) "Efficiency impr
operation in amorphous-SiG
e: H solar cells and it's a
application to tandem type
solar cells ”, S. Yoshida,
S. Yamanaka, M .; Konagai and
K. Takahashi, Conf. Rec. 19th
IEEE Photovoltaic Specil
ists Conference-1987, pp. 1
101, (3) "Stability and ter
restal application of a
-Si tandem type solar cell
ls ", A. Hiroe, H. Yamagashi,
H. Nishio, M .; Kondo, and Y. Ta
wada, Conf. Rec. 19th IEEEPh
autovoltaic Specialists Con
ference, 1987, pp. 1111, (4) "
Preparation of high quali
ty a-SiGe: H films and its
application to the high
efficiency triple-junctio
n amorphous solar cells, ”
K. Sato, K .; Kawabata, S .; Teraz
ono, H.M. Sasaki, M .; Deguchi, T .;
Itagaki, H .; Morikawa, M .; Aiga
and K. Fujikawa, Conf. Rec.
20th IEEE Photovoltaic Spe
cilists Conference, 1988 p.
p. 73, (5) USP 4,816, 082, (6) U
SP4,471,155, (7) USP4,782,3
76 mag has been reported.

A theoretical study on the characteristics of a photovoltaic device having a changed band gap has been made, for example, in 8) "A n.
over design for amorous
Silicon alloy solar cell
s ", S. Guha, J. Yang, A. Pawlik.
iewicz, T .; Glaftelter, R.M. Ros
s, and S.S. R. 0vshinsky, Conf.
Rec. 20th IEE PHOTOVOLTAIC
Speclists Conference-19
88 pp. 79, (7) "Numerical mo
de1ing of multijunction, a
morphous silicon based P-
IN solar cells ", AH Pawl.
ikiewicz and S.K. Guha, Conf.
Rec. 20th IEEE Photovoltai
c Speclists Conference-1
988 pp. 251, etc. have been reported.

In such a conventional photovoltaic element, p
/ I, n / i Insert a layer with a changed bandgap at the interface for the purpose of preventing recombination of photoexcited carriers near the interface, increasing the open-circuit voltage, and improving the carrier range of holes. is doing.

[0005]

A conventional photovoltaic device containing silicon atoms and carbon atoms and having a changed band gap is required to have higher performance and reliability in practical use.
Further improvement in suppression of recombination of photoexcited carriers, open-circuit voltage and carrier range of holes is desired.

Further, the conventional photovoltaic element has a problem that the conversion efficiency is lowered when the irradiation light applied to the photovoltaic element is weak.

Further, the conventional photovoltaic element has a problem that the photoelectric conversion efficiency is lowered when it is annealed in the presence of vibration in the i layer because of distortion.

An object of the present invention is to provide a photovoltaic element that solves the above-mentioned conventional problems. That is, the present invention is
It is an object of the present invention to provide a photovoltaic device in which recombination of photoexcited carriers is prevented and an open circuit voltage and a carrier range of holes are improved.

It is another object of the present invention to provide a photovoltaic device having improved conversion efficiency when the irradiation light applied to the photovoltaic device is low.

A further object of the present invention is to provide a photovoltaic device in which the photoelectric conversion efficiency is less likely to decrease when annealed under vibration for a long period of time.

Furthermore, the present invention has an object to provide a photovoltaic element in which the photoelectric conversion efficiency is less likely to change with a change in temperature.

A further object of the present invention is to provide a method of manufacturing a photovoltaic device which achieves the above object.

Still another object of the present invention is to provide a system using a photovoltaic element that achieves the above object.

[0014]

DISCLOSURE OF THE INVENTION The present invention has solved the problems of the prior art and, as a result of extensive studies to achieve the object of the present invention, the photovoltaic element of the present invention was found to be a silicon-based non-single-crystal semiconductor material. In a photovoltaic element configured by laminating at least a p-type layer, a photoconductive layer (a layer including a plurality of i-type layers) and an n-type layer, the photoconductive layer is on the p-type layer side. I deposited by microwave plasma CVD method located at
A laminated structure including at least a mold layer and an i-type layer located on the n-type layer side and deposited by an RF plasma CVD method, wherein the i-type layer deposited by the microwave plasma CVD method is at least silicon. An i-type layer containing atoms and carbon atoms, which is formed such that the position of the minimum value of the band gap is offset from the center of the i-type layer toward the p-type layer, and is deposited by the RF plasma CVD method. The mold layer is characterized by containing at least silicon atoms and having a layer thickness of 30 nm or less.

As a desirable mode of the photovoltaic element of the present invention, in the i-type layer deposited by the microwave plasma CVD method, the maximum band gap is at least in the p-type layer direction or the n-type layer direction. And a band gap maximum value region is 1 or more and 30 nm or less.

Further, the i-type layer formed by the microwave plasma CVD method and / or the i-type layer formed by the RF plasma CVD method contains oxygen atoms and / or nitrogen atoms.

Further, the hydrogen content contained in the i-type layer formed by the microwave plasma CVD method is changed corresponding to the content of silicon atoms.

Further, as a desirable mode of the photovoltaic element of the present invention, the group III element and the group V element of the periodic table are simultaneously doped into the i-type layer deposited by the RF plasma CVD method. It is characterized by being done.

In addition, in a desirable mode of the photovoltaic element of the present invention, at least one of the p-type layer and the n-type layer contains a Group III element and / or a Group V element of the periodic table as main constituent elements. And a layer containing a valence electron control agent and containing silicon atoms as a main constituent element. Here, the layer containing the Group III element and / or the Group V element of the periodic table as a main constituent element is preferably 1 nm or less.

The photovoltaic element manufacturing method of the present invention comprises stacking at least a p-type layer made of a silicon-based non-single-crystal semiconductor material, a photoconductive layer (a layer made of a plurality of i-type layers), and an n-type layer. In the method for manufacturing a photovoltaic element configured, the i-type layer on the p-type layer side of the photoconductive layer is changed to a source gas containing at least a silicon atom-containing gas and a carbon atom-containing gas,
Microwave plasma CV in which microwave energy lower than microwave energy necessary for 100% decomposition of the source gas and RF energy higher than the microwave energy are simultaneously applied at a pressure of 50 mTorr or less.
According to the D method, the minimum bandgap position is formed and deposited so as to be offset in the p-type layer direction from the central position of the i-type layer, and the i-type layer on the n-type layer side of the photoconductive layer is formed of silicon. It is characterized in that it is formed to 30 nm or less at a deposition rate of 2 nm / sec or less by an RF plasma CVD method using a source gas containing at least an atom-containing gas.

A desirable mode of the method for manufacturing a photovoltaic element according to the present invention is that the silicon atom-containing gas and the carbon-containing gas are added from the deposition chamber in the microwave plasma CVD method.
It is characterized in that they are mixed and deposited at a distance of m or less.

A power generation system utilizing the photovoltaic element of the present invention is for storing the photovoltaic element of the present invention and the electric power supplied from the photovoltaic element and / or supplying the electric power to an external load. At least a storage battery and a control system for monitoring the voltage and / or current of the photovoltaic element to control the power supplied from the photovoltaic element to the storage battery and / or the external load. Characterize.

[0023]

The operation will be described in detail below with reference to the drawings.

FIG. 1 is a schematic explanatory view showing an example of the photovoltaic element of the present invention. Referring to FIG. 1, the photovoltaic device of the present invention is a conductive substrate 10 having a light reflection layer and a light reflection increasing layer.
1, an n-type silicon-based non-single-crystal semiconductor layer 102, a substantially i-type non-crystal single-crystal layer 103 that is deposited by an RF plasma CVD method and contains at least silicon atoms (hereinafter, the i-type layer 103 is referred to as "i-type layer 103"). Si layer ”) and a photoconductive layer that is deposited by a microwave plasma method and that is composed of a substantially i-type non-single-crystal semiconductor layer 104 containing at least silicon atoms and carbon atoms. Single crystal semiconductor layer 105, transparent electrode 106, and collector electrode 107
Etc.

In the i-type layer formed by the microwave plasma CVD method, the minimum value of the band gap is offset to the p-type layer side, and the conduction band is formed on the p-type layer side of the i-type layer formed by the microwave plasma CVD method. Due to the large electric field, electrons and holes are efficiently separated, and recombination of electrons and holes near the interface between the p-type layer and the i-type layer formed by the microwave plasma CVD method can be reduced. Further, since the electric field in the valence band increases from the i-type layer formed by the microwave plasma CVD method toward the n-type layer, electrons excited by the microwave plasma CVD method near the i-type layer and the n-type layer are generated. The recombination of holes can be reduced.

In addition, an n-type layer and microwave plasma C
Between the i-type layer formed by the VD method, the i-type layer formed by the RF plasma CVD method at a deposition rate of 2 nm / sec or less (i
It is possible to further improve the photoelectric conversion efficiency of the photovoltaic element by inserting a (type Si layer) of 30 nm or less.
In particular, the photovoltaic element of the present invention is less likely to change the photoelectric conversion efficiency when used in an environment where the temperature changes greatly.

The i-type non-single-crystal semiconductor layer (i-type Si layer) deposited by the RF plasma CVD method has a deposition rate of 2 nm /
It is set to be sec or less, and the vapor phase reaction is less likely to occur, and the deposition is performed with low power. As a result, the packing density of the deposited film is high, and the i-type Si layer is covered with the microwave plasma C.
When laminated with the i-type layer deposited by the VD method, the interface state between the i-type layers is reduced.

Further, in the vicinity of the interface between the n-type layer and the i-type Si layer, by containing a larger amount of the valence electron control agent than in the inside of the i-type Si layer, the constituent elements peculiar to the vicinity of the interface are rapidly changed. It is possible to reduce internal stress such as strain due to, and as a result, it is possible to reduce the defect level near the interface.
As a result, the open circuit voltage and fill factor of the photovoltaic element can be improved.

In addition, by simultaneously containing a valence electron control agent that serves as a donor and a valence electron control agent that serves as an acceptor inside the i-type Si layer, the durability against photodegradation increases.
Although the details of the mechanism are unknown, it is generally believed that the dangling bonds generated by light irradiation become the recombination centers of carriers and deteriorate the characteristics of the photovoltaic device. Further, in the case of the present invention, both the valence electron control agent that serves as a donor and the valence electron control agent that serves as an acceptor are contained in the i-type layer formed by the microwave plasma CVD method.
Not activated by 00%. As a result, even if dangling bonds are generated by light irradiation, it is considered that they react with the unactivated valence electron control agent to compensate dangling bonds.

Further, even when the light intensity applied to the photovoltaic element is weak, the probability of trapping photoexcited electrons and holes is reduced because the defect level is compensated by the valence electron control agent. Further, as described above, since the dark current during reverse bias is small, sufficient electromotive force can be generated. As a result, excellent photoelectric conversion efficiency is exhibited even when the intensity of light applied to the photovoltaic element is weak.

In addition, the photoelectric conversion efficiency is less likely to decrease even when annealing is performed for a long time under vibration. Although the detailed mechanism is unknown, in the vicinity of the interface between the n-type layer and the i-type Si layer having very different constituent element ratios, a valence electron control agent serving as a donor and a valence electron control agent serving as an acceptor are simultaneously added. It is considered that the local flexibility is thereby increased, and a decrease in photoelectric conversion efficiency of the photovoltaic element can be suppressed even during annealing due to long-term vibration.

Further, a p-type layer and microwave plasma CVD
By forming an i-type layer of 30 nm or less at a deposition rate of 2 nm / sec or less between the i-type layers by the RF plasma CVD method, it is possible to further improve the photoelectric conversion efficiency of the photovoltaic element and to change the temperature. Even when used in a large environment, the photoelectric conversion efficiency is less likely to change.

In the present invention, for example, a p-type layer is used as a periodic table element.
Layers containing Group III elements as main constituent elements (hereinafter referred to as Periodic Table III
A layer containing a group element or a group V element as a main constituent element is referred to as a doping layer A) and a layer containing a valence electron control agent and containing silicon atoms as a main constituent element (hereinafter referred to as a doping layer B). With the laminated structure, the light transmittance of the p-type layer can be increased and the specific resistance of the p-type layer can be reduced. In particular, it is preferable that the side of the p-type layer in contact with the photoconductive layer is a layer containing a valence electron control agent and having silicon as a main constituent element (doping layer B).
By connecting the photoconductive layer and the p-type layer in this manner, it becomes possible to reduce defects between the photoconductive layer and the p-type layer.

The layer thickness of 0.01 to 1 nm is the optimum range for the layer thickness (doping layer A) of which group III atom is the main constituent element of the periodic table constituting the p-type layer. The content of hydrogen contained in the layer containing a Group III element of the periodic table as a main constituent element is preferably 5% or less.
The content of the valence electron control agent contained in the layer (doping layer B) containing the valence electron control agent constituting the p-type layer and having silicon atoms as the main constituent element is 1500 ppm to 10,000 p
pm is mentioned as a preferable range.

The p-type layer has been described above, but the same effects as above can be obtained by using the same laminated structure for the n-type layer.

Next, the present invention will be described with reference to band diagrams.

FIG. 2-1 is a schematic explanatory view of an example in which the band gap of the photovoltaic element of the present invention changes. This figure shows the change in the bandgap in the i-type layer based on 1/2 (Eg / 2) of the bandgap. In the figure, the left side is the n-type layer (not shown) side, and the right side is the p-type layer (not shown) side. In the example of FIG. 2A, the i-type layer (i-type Si layer) 212 by the RF plasma CVD method is provided on the n-type layer side, and the minimum value of the band gap is inside the i-type layer 211 by the microwave plasma CVD method. In the p-type layer direction, the maximum value of the band gap is in the p-type layer direction and the n-type layer direction. Similarly to FIG. 2A, FIG. 2B has an i-type Si layer 222 on the n-type layer side, and the minimum value of the band gap is p inside the i-type layer 221 formed by the microwave plasma CVD method. It is near the mold layer (not shown),
The maximum value of the band gap is configured to be in the p-type layer direction.

FIGS. 3-1 to 3-3 show an i-type layer (i-type Si layer) formed by RF plasma CVD on the n-type layer side.
The p-type layer has an i-type layer with a constant bandgap formed by the microwave plasma CVD method.
This is an example of a photovoltaic element in which the bandgap is reduced until the i-type layer by the method contacts the i-type layer having a constant bandgap. In each figure, the change in band gap is drawn based on Eg / 2, and the n-type layer (not shown) on the left side and the p-type layer (not shown) on the right side of the band diagram.

FIG. 3A shows an i-type layer 312 having a constant band gap formed by microwave plasma CVD on the p-type layer side.
And an i-type Si layer 313 having a constant band gap on the n-type layer side
Is an example of the i-type layer 311 formed by the microwave plasma CVD method in which the band gap decreases from the n-type layer side toward the i-type layer 312. The minimum value of the band gap is at the interface between the i-type layer 312 and the i-type layer 311. Further, the bonding of the band between the i-type layer 311 and the i-type layer 312 is such that the bands are discontinuously connected. By providing a region with a constant band gap in this way, it is possible to suppress dark current due to hopping conduction via the defect level in the reverse bias of the photovoltaic element as much as possible.
As a result, the open circuit voltage of the photovoltaic element increases.

The i-type Si layer 3 having a constant band gap
The layer thickness of 13 is a very important factor and the preferred layer thickness range is 1 to 30 nm. When the layer thickness of the i-type Si layer having a constant band gap is thinner than 1 nm, it is impossible to suppress the dark current due to hopping conduction via the defect level, and it is impossible to expect the open circuit voltage of the photovoltaic element to be improved. is there. On the other hand, when the thickness is thicker than 30 nm, photoexcited holes are likely to be accumulated in the vicinity of the interface between the i-type Si layer 313 having a constant band gap and the i-type layer 311 having a changed bandgap, and thus the photoexcited carriers are easily accumulated. Collection efficiency is reduced. That is, the short circuit photocurrent is reduced.

FIG. 3-2 shows RF plasma CV on the n-type layer side.
An i-type Si layer 323 having a constant bandgap formed by the D method is provided, and an i-type layer 322 having a constant bandgap formed by a microwave plasma CVD method having a larger layer thickness than that of FIG. 3A is provided on the p-type layer side. And microwave plasma CV
I-type layer 321 having a changed band gap by D method
Has a band gap decreasing toward the i-type layer 322.

FIG. 3-3 shows the i-type Si layer 334 having a constant band gap on the n-type layer side, the i-type layer 333 having a constant band gap formed by the microwave plasma CVD method, and the direction from the n-type layer direction to the p-type layer direction. I-type layer 3 by microwave plasma CVD method in which the band gap is unilaterally reduced
31 and an i-type layer 332 having a constant band gap by the microwave plasma CVD method on the p-type layer side. Between p-type layer and i-type layer 331 and between n-type layer and i-type layer 33
By providing a region having a constant band gap between 1 and 1, when a reverse bias is applied to the photovoltaic element, the dark current is further reduced and the open circuit voltage of the photovoltaic element can be increased.

FIGS. 3-4 to 3-7 show examples in which the i-type layer formed by the microwave plasma CVD method has a minimum band gap value.

The photoconductive layer of the photovoltaic element shown in FIG. 3-4 is an i-type Si layer 344 having a uniform bandgap on the n-type layer side.
And an i-type layer 343 having a uniform band gap formed by the microwave plasma CVD method, an i-type layer 341 formed by the microwave plasma CVD method having a minimum bandgap inside, which is continuously connected to the i-type layer 343, and i Mold layer 34
1 and an i-type layer 342 formed by a microwave plasma CVD method with a uniform band gap, which are continuously connected. By making the bandgap continuous, electrons and holes photoexcited in the region where the bandgap of the i-type layer changes can be efficiently collected in the n-type layer and the p-type layer, respectively. Further, in particular, the i-type layer 34 having a constant band gap
I-type layer 3 when 2, 343, 344 is as thin as 5 nm or less
The region where the bandgap of 41 sharply changes can reduce the dark current when a reverse bias is applied to the photovoltaic element, and thus the open circuit voltage of the photovoltaic element can be increased.

In the photoconductive layer of FIG. 3-5, the i-type layer 351 having a changed bandgap formed by the microwave plasma CVD method is different from the i-type layers 353 and 352 having a constant bandgap formed by the microwave plasma CVD method. It is connected continuously and relatively slowly, and it is in contact with the n-type layer and has a constant band gap i.
This is an example in which the type Si layer 354 is provided. Since the region where the band gap is constant and the region where the band gap is changing are connected gently in the direction in which the band gap widens,
The carriers photo-excited in the region where the band gap is changed are efficiently injected into the region where the band gap is constant. As a result, the collection efficiency of photoexcited carriers is increased.

Whether the region where the bandgap is constant and the region where the bandgap changes are connected continuously or discontinuously depends on whether the region where the bandgap is constant or the region where the bandgap changes abruptly. It depends on the layer thickness. When the layer thickness of the region where the band gap is constant is as thin as 5 nm or less and the band gap is changing rapidly is 10 nm or less, the region where the band gap is constant and the region where the band gap is changing are continuous. The photoelectric conversion efficiency of the photovoltaic element is higher when connected. On the other hand, when 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 to 30 nm, the band gap changes to the region where the band gap is constant. The conversion efficiency of the photovoltaic element is improved when the region in which it is connected is connected discontinuously.

In FIG. 3-6, the photoconductive layer is the i-type layer 362 by the microwave plasma CVD method on the p-type layer side, and the microwave plasma CVD having the minimum value of the band gap.
The i-type Si layer 3 in contact with the i-type layer 361 and the n-type layer
It consists of 64. FIG. 3-6 is 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. Further, it is an example in which the position where the band gap is extremely small is near the p-type layer. By connecting to a certain region with a wide band gap through the steps of gradually and rapidly expanding the band gap from the position where the band gap is extremely small, the photo-excited carriers can be efficiently used in the region where the band gap is changing. It can be collected well. Also, in FIG. 3-6, i near the n-type layer
The mold layer has a region in which the band gap changes rapidly toward the n-type layer.

In the photoconductive layer shown in FIG. 3-7, the i-type Si layer 374 in contact with the n-type layer, the i-type layer 373 having a constant band gap by the microwave plasma CVD method, and the region where the band gap has the minimum value are formed inside. The i-type layer 371 formed by the microwave plasma CVD method and the i-type layer 372 formed by the microwave plasma CVD method. Figure 3
-7 has a region with a constant bandgap in both the i-type layers on the p-type layer and n-type layer sides, and a band with two stages from the bandgap changing region in the region with a constant bandgap on the p-type layer side. In this example, the connection is made after the gap is changed, and the region where the band gap is constant on the n-type layer side is connected by the abrupt change of the band gap.

As described above, the region where the band gap is constant and the region where the band gap changes are connected in the state where the constituent elements are similar to each other, the internal strain can be reduced. As a result, even if it is annealed under vibration for a long time, i
The phenomenon that the weak bond in the layer is broken and the defect level is increased to lower the photoelectric conversion efficiency is less likely to occur, and high photoelectric conversion efficiency can be maintained.

In the present invention, the preferable range of the band gap at the band gap minimum of the i-type layer containing silicon atoms and carbon atoms is variously selected according to the spectrum of irradiation light, but is 1.6. ~ 1.8 eV is desirable.

Further, in the photovoltaic element of the present invention in which the band gap is continuously changed, the slope of the tail state of the valence band is an important factor that influences the characteristics of the photovoltaic element. It is preferable that the slope of the tail state at the minimum value of the band gap to the slope of the tail state at the maximum band gap is smoothly continuous.

Although the photovoltaic element having the pin structure has been described above, it goes without saying that the present invention can be applied to a photovoltaic element in which a pin structure such as a pinpin structure (double structure) or a pinpinpin structure (triple structure) is laminated. .

The photovoltaic element of the present invention is suitable as a top pin photovoltaic element on the light incident side of a photovoltaic element having a laminated pin structure. In the case of the double structure, the bottom photovoltaic element is a pin structure photovoltaic element whose main constituent element is silicon as the i-type layer, or i
A pin structure photovoltaic device having silicon and germanium as main constituent elements is suitable for the mold layer. Furthermore, in the case of the triple structure, the middle photovoltaic element is a pin structure photovoltaic element having silicon as a main constituent element as an i-type layer, or a pin having silicon and germanium as main constituent elements as an i-type layer. A photovoltaic device with a structure is suitable. As the bottom photovoltaic element of triple structure,
A photovoltaic element having silicon and germanium as main constituent elements is suitable for the i-type layer.

FIG. 4 is a schematic explanatory view showing an example of a manufacturing apparatus suitable for forming a deposited film of the photovoltaic element of the present invention. The manufacturing apparatus includes a deposition chamber 401 and a gas introduction pipe 41.
1, substrate 404, heater 405, vacuum gauge 402,
Conductance valve 407, auxiliary valve 408, leak valve 409, RF power source 403, RF electrode 410, source gas supply device 2000, mass flow controller 2
011 to 2017, valves 2001 to 2007, 202
1 to 2027, pressure regulators 2031 to 2037, raw material gas cylinders 2041 to 2048, and the like.

Although the details of the deposition mechanism in the deposition method of the present invention are unknown, it can be considered as follows.

A microwave energy lower than that required for 100% decomposition of the source gas is applied to the source gas, and a high RF energy is applied to the source gas at the same time as the microwave energy to form a deposited film. It is believed that the active species suitable for forming can be selected. Further, if the internal pressure in the deposition chamber when decomposing the source gas is set to 50 mTorr or less, the mean free path of the active species suitable for forming a high-quality deposited film becomes sufficiently long, so that the gas phase reaction is suppressed as much as possible. Conceivable.

And again, the internal pressure in the deposition chamber is 50 mTorr
It is considered that in the state of r or less, the RF energy has almost no effect on the decomposition of the source gas 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 at the same time as the microwave energy, the potential difference between the plasma and the substrate (+ on the plasma side and − on the substrate side). Can be large. By thus increasing the plasma potential positively with respect to the substrate, active species decomposed by microwave energy are deposited on the substrate, and at the same time, + ions accelerated by the plasma potential collide on the substrate and collide with the substrate surface. It is considered that the relaxation reaction of is promoted to obtain a good quality deposited film. This effect is particularly remarkable when the deposition rate is several nm / sec or more.

Furthermore, 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 plasma is determined by the synergy of ions and electrons. Therefore, there is an effect that spark is unlikely to occur in the deposition chamber. As a result, 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, since the flow rate and flow rate of the source gas change temporally or spatially, in the case of DC, the DC voltage is changed with time or spatially. Need to be changed appropriately.
However, in the deposited film forming method of the present invention, the ion ratio changes due to the temporal or spatial changes in the flow rate and flow rate of the source gas, and the RF self-bias automatically changes accordingly. Change. As a result, when RF is applied to the bias rod to change the raw material gas flow rate and the raw material gas flow rate ratio, the discharge is much more stable than in the case of DC bias.

In addition, in the deposited film forming method of the present invention, in order to obtain a desired change in bandgap, a silicon atom-containing gas and a carbon atom-containing gas are supplied from the deposition chamber 5 times.
It is preferable to mix at a distance of m or less. 5m
If the raw material gases are mixed further apart, the raw material gas mixing positions are far apart even if the mass flow controller is controlled in response to the desired band gap change, and therefore the raw material gas delays and the mutual diffusion of the raw material gases is delayed. Occurs, and a shift occurs with respect to a desired band gap. That is, if the mixing position of the raw material gas is too far away, the controllability of the band gap is deteriorated.

In addition to this, in order to change the hydrogen content contained in the i-type layer in the layer thickness direction, in the deposited film forming method of the present invention, RF is applied to the bias rod where the hydrogen content is desired to be increased. The RF energy applied to the bias rod may be reduced at the point where it is desired to increase the energy and reduce the hydrogen content. On the other hand, in the case of applying DC energy at the same time as RF energy, a DC voltage applied to the bias rod with a large positive polarity may be applied where the hydrogen atom content is desired to be increased, and when the hydrogen content is desired to be decreased. As for the DC voltage applied to the bias rod, a small voltage with positive polarity may be applied.

Next, the deposited film forming method of the present invention will be described in detail below.

First, a substrate 404 for forming a deposited film is attached in the deposition chamber 401 shown in FIG. 4, and the deposition chamber is evacuated to a level of 10.sup.- ⁵ torr or less. A turbo molecular pump is suitable for this exhaust, but an oil diffusion pump may be used. In the case of an oil diffusion pump, H ₂ when the internal pressure of the deposition chamber 401 becomes 10 ⁻⁴ or less so that oil does not diffuse back into the deposition chamber,
It is preferable to introduce gases such as He, Ar, Ne, Kr and Xe into the deposition chamber. After exhausting the inside of the deposition chamber sufficiently,
Gases such as ₂ , He, Ar, Ne, Kr, and Xe are introduced into the deposition chamber so that the pressure in the deposition chamber is almost the same as when the source gas for forming the deposited film is passed. The optimum pressure in the deposition chamber is 0.5 to 50 mTorr.

When the pressure in the deposition chamber becomes stable, the substrate heating heater 405 is turned on and the substrate is heated to 100 to 500 ° C.
Heat to. When the temperature of the substrate stabilizes at a predetermined temperature, stop gasses such as H ₂ , He, Ar, Ne, Kr, and Xe,
A predetermined amount of a raw material gas for forming a deposited film is introduced into a deposition chamber from a gas cylinder via a mass flow contour roller.
The supply amount of the raw material gas for forming the deposited film introduced into the deposition chamber is appropriately determined depending on the volume of the deposition chamber.
On the other hand, the internal pressure in the deposition chamber when the source gas for forming the deposited film is introduced into the deposition chamber is a very important factor in the deposited film forming method of the present invention, and the optimum internal pressure in the deposition chamber is 0.
It is 5 to 50 mTorr.

In the deposited film forming method of the present invention, the microwave energy input into the deposition chamber for forming the deposited film is an important factor. The microwave energy is appropriately determined depending on the flow rate of the raw material gas introduced into the deposition chamber, but is smaller than the microwave energy required for 100% decomposition of the raw material gas, and a preferable range is as follows. , 0.005-1 W / cm
^{Is 3} . A preferable frequency range of microwave energy is 0.5 to 10 GHz. Especially 2.
A frequency around 45 GHz is suitable. Further, in order to form a deposited film with reproducibility by the deposited film forming method of the present invention and to form a deposited film over several hours to several tens of hours, frequency stability of microwave energy is very important. . The fluctuation of the frequency is preferably within ± 2%. Further, the ripple of the microwave is preferably within ± 2%.

Further, in the method of forming a deposited film of the present invention, the RF energy which is introduced into the deposition chamber at the same time as the microwave energy is a very important factor in combination with the microwave energy, and the RF energy is preferable. The range is 0.01 to 2 W / cm ³ . RF
1 to 100 MHz can be mentioned as a preferable frequency range. Particularly, 13.56 MHz is optimum. Also R
The fluctuation of the frequency of F is within ± 2%, and a smooth waveform is preferable.

The supply of RF energy is appropriately selected according to the area ratio of the area of the bias rod for supplying RF energy and the area of ground, and the area of the bias rod for supplying RF energy is the area of ground. If it is narrower than this, it is preferable to ground the self-bias (DC component) on the power supply side for RF energy supply. Also, RF
When the self-bias (DC component) on the power supply side for energy supply is not grounded, it is preferable to make the area of the bias rod for RF energy supply larger than the area of the ground in contact with the plasma.

Such microwave energy is introduced into the deposition chamber from the waveguide section 412 through the dielectric window 413, and at the same time, RF energy is introduced into the deposition chamber from the bias power source 403 through the bias rod (RF electrode) 410. To do. In this state, the raw material gas is decomposed for a desired time to form a deposited film having a desired layer thickness on the substrate. After that, the input of microwave energy and RF energy is stopped, the deposition chamber is evacuated, and purged sufficiently with a gas such as H ₂ , He, Ar, Ne, Kr, and Xe, and then the deposited non-single-crystal semiconductor film is removed from the deposition chamber. Take it out.

In addition to the RF energy, a DC voltage may be applied to the bias rod (RF electrode) 410. Regarding the polarity of the DC voltage, it is preferable to apply the voltage so that the bias rod becomes positive. And the preferable range of the DC voltage is 10 to 300
V.

The following compounds are suitable as the compound containing a silicon atom or a carbon atom and capable of being gasified, which is used for forming the deposited film of the i-type layer of the present invention as described above.

For example, as a gasifiable compound containing silicon atoms, SiH ₄ , Si ₂ H ₆ , SiF ₄ , S
iFH ₃ , SiF ₂ H ₂ , SiF ₃ H, Si ₃ H ₈ , Si
D ₄ , SiHD ₃ , SiH ₂ D ₂ , SiH ₃ D, SiFD ₃ ,
_{SiF 2 D 2, SiD 3 H} , etc. Si ₂ D ₃ H _3, and the like.

Specific examples of the compound containing a carbon atom and capable of being gasified include CH ₄ , CD ₄ , C _n H _{2n + 2} (n is an integer), C _n H _2n (n is an integer), C ₂ H ₂ , C ₆ H ₆ , CO ₂ ,
CO etc. are mentioned.

Further, the above compounds were used as H ₂ , He, Ne and A.
It may be appropriately diluted with a gas such as r, Xe or Kr and introduced into the deposition chamber.

RF Plasma CV of Photovoltaic Device of the Present Invention
For depositing the i-type layer (i-type Si layer) by the D method, the deposition film forming apparatus by the microwave plasma CVD method shown in FIG. 4 can be used. Using the deposition film forming apparatus by the microwave plasma CVD method shown in FIG.
When forming a deposited film by the F plasma CVD method,
Instead of supplying microwave energy, the raw material gas for forming the deposited film may be decomposed only by the RF energy to form the deposited film.

The i-type layer (i-type Si) which is inserted into the n / i interface of the photovoltaic element of the present invention by the RF plasma CVD method.
Layers) are deposited as follows. First, the substrate on which the n-type layer is deposited is attached as the substrate 404 on the heater 405 in the deposition chamber 401. The door of the deposition chamber 401 is closed, and the deposition chamber is pulled up to the level of 10 ⁻³ Torr. H ₂ ,
Substrate heating gas such as He, Ne, Ar, Xe, Kr is R
Flow at the same flow rate and pressure as when performing F plasma CVD. At the same time, the substrate heating heater 405 is turned on, and the temperature of the heating heater 405 is set so that the desired substrate temperature is reached. When the substrate temperature reaches the desired temperature, the substrate heating gas is stopped and the desired source gas for forming the deposited film is supplied from the source gas supply device 2000 into the deposition chamber 401 via the auxiliary valve 408 and the gas introduction pipe 411. Introduce.

After the internal pressure of the deposition chamber has been stabilized to a desired internal pressure by the source gas, the desired RF energy from the RF power source is passed through the matching box (not shown) to the RF electrode 4.
Introduce to 10. Then, plasma is generated to continue the deposition for a desired deposition time. After deposition for the desired deposition time, stop supplying RF energy, turn off the heater for heating the substrate,
The raw material gas for forming the deposited film is stopped and the deposition chamber is sufficiently purged. After the substrate temperature has dropped to about room temperature, the substrate is taken out of the deposition chamber and the process proceeds to the next microwave plasma CVD method step.

When the i-type Si layer is deposited by the RF plasma CVD method, the substrate temperature in the deposition chamber is 100 to 350.
℃, internal pressure 0.1 to 10 Torr, RF power,
0.01-5.0 W / cm ² , the deposition rate is 0.01-
The optimum condition is 2 nm / sec.

The RF frequency is 1 MHz to 100 M
HZ is a suitable range, and particularly a frequency near 13.56 MHz is optimum. Further, in the RF method, the stability of the RF frequency is also a very important factor, and preferably ±
Within 2%. The RF power ripple is preferably 5% or less.

In the present invention, in order to control valence electrons, i
As the valence electron control agent introduced into the Si type Si layer,
Group III atoms and Group V atoms are included. As a material effectively used as a starting material for introducing a Group III atom, specifically, for introducing a boron atom, B ₂ H ₆ , B ₄ H ₁₀ ,
_{B 5 H 9, B 5 H} 11, B 6 H 10, B 6 H 12, B 6 H 14 , etc. borohydride, BF _3, BCl _3, and halogenated boron such as equal. In addition to this, AlCl ₃ , GaC
l ₃ , InCl ₃ , TlCl _{3 and the} like can also be mentioned.

Further, what is effectively used as a starting material for introducing a Group V atom is, specifically, for introducing a phosphorus atom, phosphorus hydride such as PH ₃ , P ₂ H ₄ or the like, PH ₄ I, PF ₃ , P
Phosphorus halides such as F ₅ , PCl ₃ , PCl ₅ , PBr ₃ , PBr ₅ and PI ₃ can be mentioned. In addition, AsH ₃ , As
_{F 3, AsCl 3, ASBr 3} , ASF 5, SbH 3, Sb
F ₃ , SbF ₅ , SbCl ₃ , SbCl ₅ , BiH ₃ , Bi
Other examples include Cl ₃ and BiBr ₃ .

Further, the above compounds were used as H ₂ , He, Ne and A.
It may be appropriately diluted with a gas such as r, Xe or Kr and introduced into the deposition chamber.

A preferable range of the introduction amount of the group III atom and the group V atom of the periodic table introduced into the i-type Si layer for achieving the object of the present invention is 1000 ppm or less. In order to achieve the object of the present invention, the periodic table II
It is preferable to add so that the group I atom and the group V atom are simultaneously compensated.

As a gas effectively used as a starting material for introducing nitrogen atoms or oxygen atoms into the i-type layer formed by the microwave plasma CVD method and the i-type Si layer formed by the RF plasma method, for example, as a nitrogen atom introduction gas. Is N
₂ , NH ₃ , ND ₃ , NO, NO ₂ , N ₂ O and the like can be mentioned. Further, as the oxygen atom introduction gas, O ₂ , CO, C
O ₂ , NO, NO ₂ , N ₂ O, CH ₃ CH ₂ OH, CH ₃ OH
Etc.

In the present invention, more preferable deposition apparatus is a microwave plasma CVD apparatus and an RF plasma CV.
A device in which the D device is continuously connected is preferable. The deposition chamber by the microwave plasma CVD method and the deposition chamber by the RF plasma CVD method are preferably separated by a gate. As the gate, a mechanical gate valve, a gas gate or the like is suitable.

When the p-type layer or the n-type layer has a laminated structure, the periodic table introduced in order to control the conductivity type of the non-single-crystal semiconductor layer to be the p-type or the n-type, Group III element and / or V-group. The introduction amount of the group element is preferably 500 ppm to 10%.

In the present invention, when the p-type layer or the n-type layer has a laminated structure, that is, the layer containing the group III element or / and the group V element of the periodic table as a main constituent element (doping layer A) And a p-type layer or an n-type layer having a laminated structure of a layer containing a valence electron control agent and containing silicon atoms as a main constituent element (doving layer B) is the microwave plasma CVD.
The apparatus or the RF plasma CVD apparatus can be used.

The doving layer A is formed of the above-mentioned periodic table II.
It is preferable that a gas containing a group I element and / or a group V element is used as a source gas and deposited by the microwave plasma CVD method or the RF plasma CVD method. In particular, in order to reduce the hydrogen content of the doping layer A, it is preferable to decompose and deposit the source gas with as high a power as possible.

Also in the doping layer B, the microwave plasma CV is prepared by mixing a group III element and / or a group V element of the periodic table as a valence electron control agent with a silicon atom-containing gas.
It is preferable to deposit by the D method or the RF plasma CVD method.

On the other hand, when the doping layer B containing the crystal phase is deposited by the microwave plasma CVD method, it is preferable that the RF energy is smaller than the microwave energy and the microwave energy is relatively large. The preferred microwave energy is 0.1 to 1.5 W / cm ³ . Further, in order to increase the crystal grain size, it is preferable to dilute with hydrogen, and the dilution ratio of the source gas with hydrogen gas is preferably in the range of 0.01 to 10%.

Further, the dobbing layer B containing the crystal phase is formed by RF.
When depositing by the plasma CVD method, it is preferable that the silicon atom-containing gas is diluted to 0.01 to 10% with hydrogen gas (H ₂ , D ₂ ) and the RF power is set to 1 to 10 W / cm ^2. It is a condition.

When the p-type layer and / or the n-type layer of the photovoltaic element of the present invention is formed by stacking the doping layer A and the doping layer B, it is preferable to start from the doping layer B and end with the doping layer B. It is a thing. BA for example
B, BABAB, BABABAB, BABABABAB
The configuration such as is preferable.

Particularly when the transparent electrode and the p-type layer and / or the n-type layer having a laminated structure are in contact with each other, the period of indium oxide or tin oxide forming the transparent electrode is better when the doping layer B and the transparent electrode are in contact with each other. It is possible to prevent the diffusion of the group III element and / or the group V element of the index table and reduce the decrease over time in the photoelectric conversion efficiency of the photovoltaic element.

Next, the structure of the photovoltaic element of the present invention will be described in more detail.

(Conductive Substrate) The conductive substrate may be a conductive material, or a support formed of an insulating material or a conductive material and subjected to a conductive treatment thereon. . Examples of the conductive support include NiCr, stainless steel, Al, Cr, Mo, Au, Nb, Ta, V and T.
Examples include metals such as i, Pt, Pb, and Sn, or alloys thereof.

As the electrically insulating support, a film or sheet of synthetic resin such as polyester, polyethylene, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene and polyamide, or glass, ceramics, paper, etc. Is mentioned. These electrically insulating supports preferably have at least one surface thereof subjected to a conductive treatment,
It is desirable to provide a photovoltaic layer on the surface side that has been subjected to the conductive treatment.

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 + SnO
₂ ) Conductivity is provided by providing a thin film made of, for example, NiCr, Al, Ag, Pb, Zn, Ni, if it is a synthetic resin film such as polyester film.
Au, Cr, Mo, Ir, Nb, Ta, V, Tl, Pt
A metal thin film such as is provided on the surface by vacuum vapor deposition, electron beam vapor deposition, 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 appropriately determined so that a desired photovoltaic element can be formed, but when flexibility as a photovoltaic element is required, a range in which the function as a support is sufficiently exerted Can be made as thin as possible. However, it is usually 10 μm or more in terms of production, handling and mechanical strength of the support.

(Light Reflecting Layer) As the light reflecting layer, Ag, A
A metal having a high reflectance from visible light to near infrared is suitable such as l, Cu, AlSi. These metals are suitably formed by a resistance heating vacuum evaporation method, an electron beam vacuum evaporation method, a co-evaporation method, a sputtering method, or the like. As a layer thickness of these metals as a light reflecting layer, a suitable layer thickness is 10 nm to 5000 nm. In order to texture these metals, the substrate temperature at the time of depositing these metals should be 200 ° C. or higher.

(Reflection increasing layer) Zn was used as the reflection increasing layer.
O, SnO ₂ , In ₂ O ₃ , ITO, TiO ₂ , CdO, C
The optimum ones are d ₂ SnO ₄ , Bi ₂ O ₃ , MoO ₃ , Na _x WO ₃ .

Suitable methods for depositing the reflection-increasing layer include vacuum evaporation method, sputtering method, CVD method, spray method, spin-on method, dip method and the like.

As for the layer thickness of the reflection increasing layer, the optimum layer thickness varies depending on the refractive index of the material of the reflection increasing layer.
The preferable layer thickness range is 50 nm to 10 μm. To further texture the reflection enhancing layer, the substrate temperature when depositing the reflection enhancing layer is 300 ° C.
It is preferable to increase the above.

(P-type layer or n-type layer: second and first conductivity type layers) The p-type layer or the n-type layer is an important layer that influences the characteristics of the photovoltaic element.

Examples of the amorphous material (denoted as a-) of the p-type layer or the n-type layer (a microcrystalline material (denoted as μc-) is also included in the category of amorphous materials) are, for example, a- Si:
H, a-Si: HX, a-SiC: H, a-SiC: H
X, a-SiGe: H, a-SiGeC: H, a-Si
O: H, a-SiN: H, a-SiON: HX, a-S
iOCN: HX, μc-Si: H, μc-SiC: H,
μc-Si: HX, μc-SiC: HX, μc-SiG
e: H, μc-SiO: H, μc-SiGeC: H, μ
c-SiN: H, μc-SiON: HX, μc-SiO
CN: HX, etc. p-type valence electron control agent (Periodic Table III
Examples include a material in which a group atom B, Al, Ga, In, Tl) or an n-type valence electron control agent (group V atom P, As, Sb, Bi in the periodic table) is added at a high concentration. (Poly
Is displayed), for example, poly-Si: H,
poly-Si: HX, poly-SiC: H, pol
y-SiC: HX, poly-SiGe: H, poly
-Si, poly-SiC, poly-SiGe, etc., a p-type valence electron control agent (group III atom B, Al,
Ga, In, Tl) and n-type valence electron control agents (group V atoms P, As, Sb, Bi of the periodic table) are added at high concentrations.

Particularly in the p-type layer or the n-type layer on the light incident side,
A crystalline semiconductor layer with little light absorption or an amorphous semiconductor layer with a wide band gap is suitable.

The amount of Group III atoms added to the p-type layer and the amount of Group V atoms added to the n-type layer are 0.1 to 0.1%.
The optimum amount is 50 at%.

Hydrogen atoms (H, D) or halogen atoms contained in the p-type layer or the n-type layer serve to compensate dangling bonds in the p-type layer or the n-type layer, It improves the doping efficiency of the layer. The optimum amount of hydrogen atoms or halogen atoms added to the p-type layer or the n-type layer is 0.1 to 40 at%. Especially p
When the type layer or the n-type layer is crystalline, the optimum amount of hydrogen atoms or halogen atoms is 0.1 to 8 at%. Further, a preferable distribution form is one in which the content of hydrogen atoms and / or halogen atoms is largely distributed on the interface side of each of the p-type layer / i-type layer and the n-type layer / i-type layer. The content of hydrogen atoms and / or halogen atoms is preferably in the range of 1.1 to 2 times the content in the bulk. Thus, by increasing the content of hydrogen atoms or halogen atoms in the vicinity of each interface of the p-type layer / i-type layer and the n-type layer / i-type layer, the defect level and mechanical strain near the interface are reduced. It is possible to increase the photovoltaic power and the photocurrent of the photovoltaic device of the present invention.

Regarding the electrical characteristics of the p-type layer and the n-type layer of the photovoltaic element, the activation energy is preferably 0.2 eV or less, and most preferably 0.1 eV or less. The specific resistance is preferably 100 Ωcm or less, and most preferably 1 Ωcm or less. Furthermore, the layer thickness of the p-type layer and the n-type layer is 1 to
50 nm is preferable and 3 to 10 nm is optimum.

As a source gas suitable for depositing the p-type layer or the n-type layer of the photovoltaic element, a gasifiable compound containing a silicon atom, a gasifiable compound containing a germanium atom, or a carbon atom was contained. Examples thereof include compounds that can be gasified, and mixed gases of the compounds.

Specific examples of the gasifiable compound containing a silicon atom include SiH ₄ , Si ₂ H ₆ and Si.
F ₄ , SiFH ₃ , SiF ₂ H ₂ , SiF ₃ H, Si ₃ H ₈ ,
SiD ₄ , SiHD ₃ , SiH ₂ D ₂ , SiH ₃ D, SiF
_{D 3, SiF 2 D 2,} SiD 3 H, etc. Si ₂ D ₃ H _3, and the like.

Specific examples of the gasifiable compound containing a germanium atom include GeH ₄ , GeD ₄ , and Ge.
F ₄ , GeFH ₃ , GeF ₂ H ₂ , GeF ₃ H, GeHD ₃ ,
_{GeH 2 D 2, GeH 3 D} , GeH 6, GeD 6 , and the like.

Specific examples of the gasifiable compound containing a carbon atom include CH ₄ , CD ₄ , C _n H _{2n + 2} (n is an integer), C _n H _2n (n is an integer), C ₂ H ₂ , C ₆ H ₆ , CO ₂ ,
CO etc. are mentioned.

The substances introduced into the p-type layer or the n-type layer for controlling the valence electrons are the periodic table group III source and group V source.
Group atoms can be mentioned.

As a starting material effectively used for introducing a group III atom, specifically, for introducing a boron atom, B ₂ H ₆ , B ₄ H ₁₀ , B ₅ H ₉ , B ₅ H ₁₁ , B ₆ H
₁₀ , B ₆ H ₁₂ , B ₆ H _14, etc. borohydrides, BF ₃ , BC
Examples thereof include boron halides such as l ₃ and the like.
In addition, AlCl ₃ , GaCl ₃ , InCl ₃ , TlC
Examples include l _{3 and the} like. B ₂ H ₆ and BF ₃ are particularly suitable.

What is effectively used as a starting material for introducing a group V atom is specifically PH for introducing a phosphorus atom.
₃ , Phosphorus hydride such as P ₂ H ₄ , PH ₄ I, PF ₃ , PF ₅ , PC
Examples thereof include phosphorus halides such as l ₃ , PCl ₅ , PBr ₃ , PBr ₅ , and PI ₃ . In addition, AsH ₃ , AsF ₃ , AsC
l ₃ , ASBr ₃ , ASF ₅ , SbH ₃ , SbF ₃ , Sb
F ₅ , SbCl ₃ , SbCl ₅ , BiH ₃ , BiCl ₃ , B
iBr ₃ etc. can also be mentioned. Particularly, PH ₃ and PF ₃ are suitable.

In addition, the gasifiable compound is replaced by 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.

The p-type layer or the n-type layer deposition method suitable for the photovoltaic device is the RF plasma CVD method and the microwave plasma CVD method.

Particularly when the deposition is performed by the RF plasma CVD method, the capacitive coupling type RF plasma CVD method is suitable.
When the p-type layer or the n-type layer is deposited by the RF plasma CVD method, the substrate temperature in the deposition chamber is 100 to 350 ° C., the internal pressure is 0.1 to 10 torr, and the RF power is 0.01 to.
5.0 W / cm ² , deposition rate is 0.1-30 A / se
c is mentioned as an optimal condition.

In particular, when depositing a layer having a small band of light absorption or a wide band gap, such as a microcrystalline semiconductor or a-SiC: H, the source gas is diluted with hydrogen gas 2 to 100 times, and the RF power is relatively high. Is preferably introduced. The suitable range of the RF frequency is 1 MHz to 100 MHz, and a frequency near 13.56 MHz is particularly suitable.

When the p-type layer or the n-type layer is deposited by the microwave plasma CVD method, the microwave plasma CVD apparatus introduces microwaves into the deposition chamber through a dielectric window (alumina ceramics or the like) by a waveguide. The method of doing is suitable.

The deposition film forming method of the present invention is also a suitable deposition method for depositing a p-type layer or an n-type layer by the microwave plasma CVD method, but it can be applied to a photovoltaic element under wider deposition conditions. It is possible to form various deposited films.

When a p-type layer or an n-type layer is deposited by a microwave plasma CVD method other than the method of the present invention, the substrate temperature in the deposition chamber is 100 to 400 ° C., and the internal pressure is 0.5 to 30.
mTorr, microwave power 0.01 to 1 W / cm
The frequency of ³ microwaves is preferably 0.5 to 10 GHz.

In particular, when depositing a layer having a small band of light absorption or a wide bandgap such as a microcrystalline semiconductor or a-SiC: H, the source gas is diluted 2 to 100 times with hydrogen gas, and the microwave power is relatively high. It is preferable to introduce high power.

(I-Type Layer by Microwave Plasma CVD Method) In the photovoltaic device, the i-type layer is an important layer for generating and transporting carriers with respect to irradiation light.

As the i-type layer, it is possible to use only p-type and slightly n-type layers. The i-type layer of the photovoltaic device of the present invention contains i-type silicon atoms and carbon atoms. The bandgap changes smoothly in the layer thickness direction, and the minimum value of the bandgap deviates from the central position of the i-type layer toward the interface between the p-type layer and the i-type layer. In the i-type layer, a material in which a valence electron control agent that serves as a donor and a valence electron control agent that serves as an acceptor are simultaneously doped is more suitable.

The hydrogen atom (H, D) or the halogen atom (X) contained in the i-type layer serves to compensate dangling bonds in the i-type layer, and the mobility and life of the carrier in the i-type layer. To improve the product of P-type layer / i-type layer, n-type layer /
It has a function of compensating for the interface state of each interface of the i-type layer, and has an effect of improving the photovoltaic power, the photocurrent and the photoresponsiveness of the photovoltaic device. The optimum content of hydrogen atoms and / or halogen atoms contained in the i-type layer is 1 to 40 at%.

Particularly, p-type layer / i-type layer, i-type layer / i-type Si
A preferred distribution form is one in which the content of hydrogen atoms and / or halogen atoms is largely distributed on each interface side of the layer, and the content of hydrogen atoms and / or halogen atoms near the interface is A preferable range is 1.1 to 2 times the content. Further, it is preferable that the hydrogen atom content and / or the halogen atom content is changed in the opposite direction to the increase / decrease direction of the silicon atom content. The content of hydrogen atoms and / or halogen atoms at the maximum content of silicon atoms is 1 to 10 at
% Is a preferable range and 0.3 to 0.8 times the maximum region of the content of hydrogen atoms and / or halogen atoms is a preferable range.

The content of hydrogen atoms and / or halogen atoms is changed in the direction opposite to the direction of the change of the content of silicon atoms, that is, in accordance with the band gap, hydrogen atoms and / or halogens are provided in a narrow band gap. The atomic content is low. Although the details of the mechanism are unknown, according to the deposited film forming method of the present invention, in the deposition of the alloy-based semiconductor containing silicon atoms and carbon atoms, there are differences in the ionization rates of silicon atoms and carbon atoms. It is considered that there is a difference in energy acquired by the atoms, and as a result, even if the hydrogen-containing content and / or the halogen-containing 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 trace amount of oxygen and / or nitrogen of 100 ppm or less 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 will be. The reason for this is unknown in detail, but since the composition ratio of silicon atoms and carbon atoms changes continuously in the layer thickness direction, it is better than when silicon atoms and carbon atoms are mixed at a constant ratio. It is considered that the residual strain tends to increase. By adding oxygen atoms and / or nitrogen atoms to such a system, structural strain can be reduced, and as a result, 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 or decreases according to the content of carbon atoms is preferable. This distribution is a distribution corresponding to the distribution of hydrogen atoms and / or halogen atoms, but it is considered that such distribution is preferable because of the effect of removing structural strain and the effect of reducing dangling bonds. .

Further, by distributing such hydrogen atoms (or / and halogen atoms) and oxygen atoms (or / and nitrogen atoms), the tail states of the valence band and the conduction band are smoothly and continuously connected. Is.

The layer thickness of the i-type layer largely depends on the structure of the photovoltaic element (for example, single cell, tandem cell, triple cell) and the bandgap of the i-type layer, but is 0.05-.
The optimum layer thickness is 1.0 μm.

The i-type layer containing silicon atoms and carbon atoms according to the deposited film forming method of the present invention has a deposition rate of 2.5 n.
Even if it is increased to m / sec or more, the tail state on the side of the valence band is small, and the tilt of the tail state is 60 m.
It is eV or less, and the density of dangling bonds by electron spin resonance (esr) is 10 ¹⁷ / cm ³ or less.

The band gap of the i-type layer is p-type layer / i
It is preferable to design so as to be wide on each interface side of the mold layer and the n-type layer / i-type layer. By designing in this way, the photovoltaic power and photocurrent of the photovoltaic element can be increased, and photodegradation and the like when used for a long time can be prevented.

(I-type layer formed by RF plasma CVD method: i
Type Si layer) i-type layer formed by RF plasma CVD is 2n
It is deposited at a deposition rate of m / sec or less, and the content of hydrogen atoms and / or halogen atoms contained in the deposited film is preferably in the range of 1 to 40 at%. The bonding state of hydrogen atoms and / or halogen atoms is preferably a state in which one hydrogen atom is bonded to a silicon atom or a state in which one halogen atom is bonded. The value obtained by dividing the full width at half maximum of the 2000 cm ^-1 peak in the infrared absorption spectrum showing the state where one hydrogen atom is bonded to the silicon atom by the peak height is the peak at 2000 cm ^-1 of the i-type layer by the microwave plasma CVD method It is preferable that the width is larger than the value obtained by dividing the half-value width of 1 by the peak height.

(Transparent Electrode) As the transparent electrode, indium oxide and indium-tin oxide transparent electrodes are suitable.

The transparent electrode is deposited as follows.
The sputtering method and the vacuum evaporation method are the most suitable deposition methods for depositing the transparent electrode.

In a magnetron sputtering apparatus, when a transparent electrode made of indium oxide is deposited on a substrate, a target made of metal indium (In) or indium oxide (In ₂ O ₃ ) is used. When a transparent electrode made of indium tin oxide is deposited on the substrate, the target is metallic tin (S
n), metallic indium or an alloy of metallic tin and metallic indium, tin oxide, indium oxide, indium-tin oxide, etc. are appropriately combined and used.

When depositing by the sputtering method, the substrate temperature is an important factor, and 25 ° C. to 600 ° C. is mentioned as a preferable range. Examples of the gas for sputtering include inert gases such as argon gas (Ar), neon gas (Ne), xenon gas (Xe), and helium gas (He), and Ar gas is most suitable. Further, it is preferable to add oxygen gas (O ₂ ) to the inert gas as needed. Especially when a metal is used as a target, oxygen gas (O ₂ ) is essential.

Further, when the target is sputtered with the above-mentioned inert gas or the like, the pressure of the discharge space is 0.1 to 50 mTorr in order to perform the sputtering effectively.
r is mentioned as a preferable range.

As the power source, a DC power source and an RF power source are suitable. A suitable power range for the 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, and the optimum deposition rate is 0.0
It is in the range of 1 to 10 nm / sec. The layer thickness of the transparent electrode is preferably deposited under conditions that satisfy the conditions of the antireflection film. As a specific layer thickness of the transparent electrode, 50 to 300 nm is mentioned as a preferable range.

Suitable vapor deposition sources for depositing transparent electrodes in the vacuum vapor deposition method include metal tin, metal indium, and
An indium-tin alloy is mentioned. Moreover, the range of 25 ° C. to 600 ° C. is a suitable range for the substrate temperature when depositing the transparent electrode.

Further, when the transparent electrode is deposited, the deposition chamber is depressurized to the level of 10 ⁻⁶ torr or less and then oxygen gas (O ₂ ) is added.
Is required 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 vapor deposition source reacts with oxygen in the vapor phase to deposit a good transparent electrode.

Further, RF power may be introduced at the above vacuum level to generate plasma, and vapor deposition may be performed through the plasma. The preferable range of the deposition rate of the transparent electrode under the above conditions is 0.01 to 10 nm / sec. If the deposition rate is less than 0.01 nm / sec, the productivity will be reduced, and if it is more than 10 nm / sec, a rough film will be formed and the transmittance, the conductivity and the adhesion will be reduced.

Next, the power generation system of the present invention will be described.
The power generation system of the present invention includes the above-described photovoltaic element of the present invention and the power supplied from the photovoltaic element to a storage battery and / or an external load while monitoring the voltage and / or current of the photovoltaic element. It is characterized by comprising a control system for controlling, and a storage battery for storing and / or supplying the power supplied from the photovoltaic element to an external load.

FIG. 18 shows an example of the power supply system of the present invention, which is a basic circuit for charging and power supply 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) that monitors the voltage and controls the voltage, a storage battery, a load, and the like.
A silicon diode, a Schottky diode, or the like is suitable as the backflow prevention diode. As a storage battery,
Examples include nickel-cadmium batteries, rechargeable silver oxide batteries, lead-acid batteries, flywheel energy storage units.

The voltage control circuit is almost equal to the output of the solar cell until the battery is fully charged, but when the battery is fully charged, the charging current is stopped by the charging control IC.

The solar cell system utilizing such 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 device 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 sufficiently functions as an electromotive force element, it exhibits excellent stability.

[0148]

EXAMPLES The effects of the present invention will be described in detail below by the production of the non-single-crystal silicon carbide solar cell of the present invention, but the present invention is not limited thereto.

Example 1 First, a substrate was manufactured.
A 50 × 50 mm ² stainless steel substrate was ultrasonically cleaned with acetone and isopropanol and dried. Layer thickness 0.3 on the surface of stainless steel substrate at room temperature using the sputtering method.
A reflection layer of Ag (silver) having a thickness of 1.0 μm and a reflection enhancement layer of ZnO (zinc oxide) having a layer thickness of 1.0 μm at 350 ° C. were formed on the reflection layer.

Next, the source gas supply device 200 shown in FIG.
0 and a deposition apparatus 400 using a glow discharge decomposition method to manufacture a semiconductor layer on the reflection increasing layer.
In the gas cylinders 2041 to 2047 in the figure, raw material gases for producing the photovoltaic element of the present invention are sealed, 2041 is a SiH ₄ gas (purity 99.999%) cylinder, and 2042 is a CH ₄ gas. (Purity 99.9999%)
Cylinder 2043 is H ₂ gas (purity 99.9999%)
Cylinder, 2044 is PH ₃ gas diluted to 100 ppm with H ₂ gas (purity 99.99%, hereinafter referred to as “PH ₃ / H ₂ ”) cylinder, 2045 is B ₂ H diluted to 100 ppm with H ₂ gas. ₆ gases (purity 99.99%, hereinafter "B ₂
H ₆ / H ₂ "and abbreviated) bomb, 2046 NH ₃ gas (99.9999% purity diluted to 1% with H ₂ gas,
Hereinafter, abbreviated as "NH ₃ / H ₂ ") cylinder, 2047 is H
O ₂ gas diluted to 1% with e gas (purity 99.999
9%, hereinafter abbreviated as "O ₂ / He") cylinder.
When attaching the gas cylinders 2041 to 2047 in advance, the respective gases were introduced into the gas pipes up to the valves 2021 to 2027, and the pressure of each gas was adjusted to ² kg / cm ² by the pressure adjusters 2031 to 2037. SiH ₄
The gas and CH ₄ gas were mixed 0.5 m from the deposition chamber.

Next, the back surface of the substrate 404 on which the reflection layer and the reflection increasing layer are formed is brought into close contact with the heater 405,
When the leak valve 409 of the deposition chamber 401 is closed, the conductance valve 407 is fully opened, the inside of the deposition chamber 401 is evacuated by a vacuum pump (not shown), and when the reading of the vacuum gauge 402 becomes about 1 × 10 ⁻⁴ Torr. With valve 2001
~ 2007, the auxiliary valve 408 is opened, the inside of the gas pipe is evacuated, and the reading of the vacuum gauge 402 is again about 1 × 10 ^-4.
At Torr, the valves 2001 to 2007 were closed, 2031 to 2037 were gradually opened, and each gas was introduced into the mass flow controllers 2011 to 2017.

After the preparation for film formation is completed as described above, an n-type layer, an i-type Si layer, an i-type layer and a p-type layer are formed on the substrate 404.
The semiconductor layer of the mold layer was manufactured.

To form the n-type layer, the auxiliary valve 40
8. The valve 2003 is gradually opened, H ₂ gas is introduced into the deposition chamber 401 through the gas introduction pipe 411, the mass flow controller 2013 is set so that the H ₂ gas flow rate is 50 sccm, and the pressure in the deposition chamber is set to 1 .0 Tor
The conductance valve was adjusted while observing the vacuum gauge 402 so as to be r, and the heater 405 was set so that the temperature of the substrate 404 became 350 ° C. When the substrate is sufficiently heated, the valves 2001 and 2004 are gradually opened to add SiH ₄ gas and PH ₃ / H ₂ gas to the deposition chamber 40.
It was made to flow into 1. At this time, the SiH ₄ gas flow rate is 2 sc
cm, H ₂ gas flow rate was 100 sccm, and PH ₃ / H ₂ gas flow rate was adjusted to 20 sccm by mass flow controllers 2011, 2013, and 2014, respectively.
The opening of the conductance valve 407 was adjusted while observing the vacuum gauge 402 so that the pressure in the deposition chamber 401 was 1.0 Torr. After confirming that the shutter 415 is closed, the power of the RF power source is set to 0.007 W / cm ³ , RF power is introduced to the RF electrode 410 to cause glow discharge, the shutter is opened, and the substrate 404 is placed. Then, the production of the n-type layer was started, and when the n-type layer having a layer thickness of 20 nm was produced, the shutter was closed, the RF power was turned off, the glow discharge was stopped, and the formation of the n-type layer was completed. Valves 2001, 2
004 is closed, and SiH ₄ gas into the deposition chamber 401, P
Stopping the flow of H ₃ / H ₂ gas for 5 minutes, after which continued to flow H ₂ gas into the deposition chamber 401, closing the outflow valves 2003, it was evacuated deposition chamber 401 and the gas pipes.

Next, in order to form the i-type Si layer, the valve 2003 is gradually closed, H ₂ gas is introduced into the deposition chamber 401, and the mass flow controller 2013 is operated so that the H ₂ gas flow rate becomes 50 sccm. Adjusted with. Adjust the conductance valve while watching the vacuum gauge 402 so that the pressure in the deposition chamber becomes 1.5 Torr, and set the heater 405 so that the temperature of the substrate 404 becomes 250 ° C.
When the substrate was sufficiently heated, the valve 2001 was gradually opened to allow SiH ₄ gas to flow into the deposition chamber 401. At this time, the SiH ₄ gas flow rate was adjusted to ₂ sccm and the H ₂ gas flow rate was adjusted to 100 sccm by each mass flow controller. The pressure in the deposition chamber 401 is
The opening of the conductance valve 407 was adjusted while observing the vacuum gauge 402 so as to be 1.5 Torr. RF power is set to 0.007 W / cm ³ and RF power is introduced,
Glow discharge was generated in the discharge space 406. The shutter 415 was opened, and the formation of the i-type Si layer on the n-type layer was started at a deposition rate of 0.1 nm / sec.

When the i-type Si layer having a layer thickness of 20 nm was produced, the shutter was closed, the RF power source was turned off, the glow discharge was stopped, and the formation of the i-type Si layer was completed. The valve 2001 is closed to stop the inflow of SiH ₄ gas into the deposition chamber 401,
After continuously flowing H ₂ gas into the deposition chamber 401 for 5 minutes,
The valve 2003 was closed, and the inside of the deposition chamber 401 and the gas pipe were evacuated.

Next, to prepare the 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. Adjusting the conductance valve while watching the vacuum gauge 402 so that the pressure in the deposition chamber is 0.01 Torr, and setting the heater 405 so that the temperature of the substrate 404 becomes 350 ° C.
When the substrate is sufficiently heated, the valve 2001,
2002 was gradually opened, and SiH ₄ gas and CH ₄ gas were caused to flow into the deposition chamber 401. At this time, the mass flow controllers were adjusted so that the SiH ₄ gas flow rate was 100 sccm, the CH ₄ gas flow rate was 30 sccm, and the H ₂ gas flow rate was 300 sccm. The pressure in the deposition chamber 401 is
The opening of the conductance valve 407 was adjusted while observing the vacuum gauge 402 so as to be 0.01 Torr. next,
Set the power of the RF power source 403 to 0.40 W / cm ³ ,
It was applied to the RF electrode 410. After that, the power of the μW power source (not shown) is set to 0.20 W / cm ³ , and the dielectric window 413 is set.
ΜW electric power was introduced into the deposition chamber 401 to generate glow discharge, the shutter was opened, and the production of the i-type layer on the i-type Si was started. Using a computer connected to the mass flow controller, change the flow rates of SiH ₄ gas and CH ₄ gas according to the flow rate change pattern shown in FIG.
When the i-type layer having a layer thickness of 300 nm was prepared, the shutter was closed, the μW power supply was turned off to stop the glow discharge, and then the RF power supply 403 was turned off to complete the production of the i-type layer. The valves 2001 and 2002 are closed to stop the inflow of SiH ₄ gas and CH ₄ gas into the deposition chamber 401, and H ₂ gas is continuously flowed into the deposition chamber 401 for 5 minutes, and then the valve 2003.
Was closed and the inside of the deposition chamber 401 and the gas pipe were evacuated.

[0157] To produce a p-type layer, the valve 2003 was gradually opened, introducing H ₂ gas into the deposition chamber 401, H ₂
The mass flow controller 2013 adjusted the gas flow rate to 50 sccm. The pressure in the deposition chamber is 2.0
While adjusting the conductance valve while watching the vacuum gauge 402 so as to be Torr, the aging heater 405 is set so that the temperature of the substrate 404 becomes 200 ° C., and when the substrate is sufficiently heated, valves 2001, 2002 and 2 are added.
Gradually open 005, SiH ₄ gas, CH ₄ gas, B ₂
H ₆ / H ₂ gas was caused to flow into the deposition chamber 401. At this time,
SiH ₄ gas flow rate is 1 sccm, CH ₄ gas flow rate is 0.5
sccm, H ₂ gas flow rate is 100 sccm, B ₂ H ₆ / H ₂
Each mass flow controller adjusted the gas flow rate to 100 sccm. The pressure inside the deposition chamber 401 was adjusted to 2.0 Torr by adjusting the opening of the conductance valve 407 while watching the vacuum gauge 402.

The RF power source was set to 0.20 W / cm ³ ,
RF power was introduced to cause glow discharge, the shutter 415 was opened, and formation of the p-type layer on the i-type layer was started. When the p-type layer having a layer thickness of 10 nm was produced, the shutter was closed, the RF power source was turned off, the glow discharge was stopped, and the formation of the p-type layer was completed. The valves 2001, 2002 and 2005 are closed, and SiH ₄ gas, CH ₄ gas, B _{2 in the} deposition chamber 401 are closed.
Stopping the flow of H ₆ / H ₂ gas for 5 minutes, after which continued to flow H ₂ gas into the deposition chamber 401, closing the valve 2003 was evacuated deposition chamber 401 and the gas pipes. The auxiliary valve 408 was closed and the leak valve 409 was opened to leak the deposition chamber 401.

Next, ITO (In ₂ O ₃ + SnO ₂ ) having a layer thickness of 80 nm was vapor-deposited as a transparent electrode on the p-type layer by a usual vacuum vapor deposition method. Next, a current collecting electrode made of chromium (Cr) and having a layer thickness of 10 μm was deposited on the transparent electrode by a usual vacuum deposition method.

Thus, the production of the non-single-crystal silicon carbide solar cell was completed. This solar cell is referred to as (SC Ex 1), and Table 1 shows conditions for forming the n-type layer, the i-type Si layer, the i-type layer, and the p-type layer.

Comparative Example 1-1 When forming the i-type layer,
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 pattern shown in FIG. 6, under the same conditions and the same procedure as in Example 1, the reflection layer, the reflection increasing layer, and the reflection layer were formed on the substrate. A solar cell was produced by forming an n-type layer, an i-type Si layer, an i-type layer, a p-type layer, a transparent electrode, and a collector electrode. This solar cell will be referred to as (SC ratio 1-1).

Comparative Example 1-2 When forming the i-type layer,
A reflective layer, a reflection-increasing layer, an n-type layer, an i-type Si layer, an i-type layer, and p were formed on a substrate under the same conditions and the same procedure as in Example 1 except that the μW power was 0.5 W / cm ^3. Mold layer, transparent electrode,
A collector electrode was formed to produce a solar cell. This solar cell will be called (SC ratio 1-2).

Comparative Example 1-3 When forming the i-type layer,
Example 1 except that the RF power was 0.15 W / cm ^3.
Under the same conditions and the same procedure as above, on the substrate, a reflection layer, a reflection increasing layer, an n-type layer, an i-type Si layer, an i-type layer, a p-type layer, a transparent electrode,
A collector electrode was formed to produce a solar cell. This solar cell will be called (SC ratio 1-3).

Comparative Example 1-4 When forming the i-type layer,
μW power 0.5 W / cm ³ , RF power 0.55 W /
The same conditions and the same procedure as in Example 1 except that the thickness was changed to cm ³ , and the reflective layer, the reflection increasing layer, the n-type layer, and the i-type Si were formed on the substrate.
A layer, an i-type layer, a p-type layer, a transparent electrode, and a collector electrode were formed to produce a solar cell. This solar cell will be referred to as (SC ratio 1-4).

<Comparative Example 1-5> When forming the i-type layer,
Except that the internal pressure is 0.08 Torr, a reflective layer, a reflective increasing layer, and
A mold layer, an i-type Si layer, an i-type layer, a p-type layer, a transparent electrode, and a collector electrode were formed to produce a solar cell. This solar cell (S
C ratio 1-5).

<Comparative Example 1-6> Example 1 was repeated except that the deposition rate was set to 3 nm / sec when the i-type Si layer was formed.
Under the same conditions and the same procedure as above, on the substrate, a reflection layer, a reflection increasing layer, an n-type layer, an i-type Si layer, an i-type layer, a p-type layer, a transparent electrode,
A collector electrode was formed to produce a solar cell. This solar cell will be referred to as (SC ratio 1-6).

<Comparative Example 1-7> When the i-type Si layer was formed, a reflective layer, a reflection increasing layer, and a reflective layer were formed on the substrate under the same conditions and the same procedure as in Example 1, except that the layer thickness was 40 nm. A solar cell was produced by forming an n-type layer, an i-type Si layer, an i-type layer, a p-type layer, a transparent electrode, and a collector electrode. This solar cell (SC
The ratio 1-7) will be called.

The manufactured solar cells (SC Ex 1) and (SC
The initial photoelectric conversion efficiency (photovoltaic power / incident optical power) and durability characteristics of the ratios 1-1) to (SC ratio 1-7) were evaluated.
As for the initial photoelectric conversion efficiency, the solar cell manufactured was AM-1.
5 (100 mW / cm ² ) under irradiation of light, VI
The characteristics were measured and determined.

As a result of the measurement, the initial photoelectric conversion efficiencies of (SC ratio 1-1) to (SC ratio 1-7) for the (SC Ex 1) solar cell 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 characteristics of the manufactured solar cell were 70% humidity,
Installed in a dark place with a temperature of 60 ° C, amplitude 1m at 3600 rpm
AM1.5 (100 m after applying vibration of m for 24 hours
It was carried out by determining the decrease in photoelectric conversion efficiency under irradiation with W / cm ² ) (photoelectric conversion efficiency after durability test / initial photoelectric conversion efficiency).

As a result of the measurement, the decrease in photoelectric conversion efficiency of (SC ratio 1-1) to (SC ratio 1-7) was as follows for the solar cell of (SC Ex 1).

(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 barium borosilicate glass (7059 manufactured by Corning Corp.) Except that the substrate was used 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 the i-type layer of Example 1, an i-type layer having a thickness of 1 μm was formed on the substrate 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 produced sample for measuring physical properties were analyzed to find the relationship between the composition ratio of Si (silicon) atoms and C (carbon) atoms and the bandgap. The results of the band gap and composition analysis are shown in Table 2 and FIG.

Here, the bandgap was measured by measuring the glass substrate on which the i-type layer was prepared with a spectrophotometer (3 manufactured by Hitachi Ltd.).
30 type), the wavelength dependence of the absorption coefficient of the i type layer was measured, and the i type was measured by the method described in p109 of "amorphous solar cell" (Kiyo Takahashi, Seikyo Konagai Co., Ltd.). The band gap of the layer was determined. For composition analysis, a stainless steel substrate having an i-type layer was placed on an Auger electron spectroscopy analyzer (JAMP-3 manufactured by JEOL Ltd.) to analyze Si atoms and C
The composition ratio of atoms was measured.

Further, using a barium borosilicate glass substrate,
Under the same manufacturing conditions as the i-type Si layer of Example 1, i
A type Si layer was formed to a thickness of 1 μm to prepare a band gap measurement sample. This sample is called (SP1-8). The band gap of the sample manufactured by the above-described measurement method was 1.75 eV.

Next, the manufactured solar cell (SC Ex 1),
The composition analysis in the layer thickness direction of Si atoms and C atoms in the i-type layer of (SC ratio 1-1) to (SC ratio 1-7) was performed by the same method as the above composition analysis.

(SP1-1) to (SP1-7), (SP
From the relationship between the composition ratio of Si atoms and C atoms and the band gap obtained in 1-8), the change in the band gap in the layer thickness direction of the i-type layer and the i-type Si layer was obtained. The result is shown in FIG. As can be seen from FIG. 8, (SC actual 1), (SC ratio 1-
In the solar cells of 2) to (SC ratio 1-7), the position of the minimum value of the band gap is offset from the central position of the i-type layer toward the p / i interface, and the solar cell of (SC ratio 1-1) In the battery, it was found that the position of the minimum value of the band gap is offset in the n / i interface direction from the position of the center of the i-type layer.

As described above, (SC Ex 1), (SC Ratio 1-1) to
The change in the band gap with respect to the layer thickness direction (SC ratio 1-7) is caused by the source gas containing Si (SiH ₄ gas in this case) and the source gas containing C (CH in this case) that are introduced into the deposition chamber. It was found that it depends on the ratio of ₄ ).

<Comparative Example 1-8> The non-single crystal carbonization was performed under the same conditions as in Example 1 except that the μW power and the RF power introduced when forming the i-type layer in Example 1 were variously changed. Several silicon solar cells were produced.

FIG. 9 is a graph showing the relationship between μW power and deposition rate. It was found that the deposition rate did not depend on the RF power, and became constant when the μW power was 0.32 W / cm ³ or more, and the SiH ₄ gas and the CH ₄ gas that were the raw material gases were 100% decomposed by this power.

In addition, AM1.5 (1
FIG. 10 shows the result of measuring the initial photoelectric conversion efficiency by irradiating with light of 00 mW / cm ² ). 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 1. As can be seen from the figure, μW power decomposes SiH ₄ gas and CH ₄ gas by 100% μW power (0.32 W / cm ³ ).
It has been found below that when the RF power is greater than the μW power, the initial photoelectric conversion efficiency is significantly improved.

<Comparative Example 1-9> When the i-type layer is formed in Example 1, the flow rate of the gas introduced into the deposition chamber 401 is set to SiH ₄
Gas was changed to 50 sccm, CH ₄ gas was changed to 10 sccm, H ₂ gas was not introduced, and μW electric power and RF electric power were variously changed to manufacture some non-single-crystal silicon carbide solar cells. The 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 as in Comparative Example 1-8 and became constant when the μW power was 0.18 W / cm ³ or more. It was found that the source gas SiH ₄ gas and CH ₄ gas were completely decomposed by this μW power. Further, when the initial photoelectric conversion efficiency of the solar cell when irradiated with AM1.5 light was measured, the result showed the same tendency as in FIG. That is, the μW power is SiH ₄
It was found that the initial photoelectric conversion efficiency is significantly improved when the power of the gas and the CH ₄ gas is decomposed by 100% or less and the RF power is higher than the μW power (0.18 W / cm ³ ).

<Comparative Example 1-10> When the i-type layer is formed in Example 1, the flow rate of the gas introduced into the deposition chamber 401 is set to SiH.
₄ gas 200sccm, CH ₄ gas 50sccm, H ₂ gas 500sccm, and substrate temperature 300 ° C.
The heating heater settings were changed so that the μW electric power and the RF electric power were changed variously, and several non-single-crystal silicon carbide solar cells were produced. The other conditions were the same as in Example 1.

When the relationship between the deposition rate and the μW power and RF power was examined, the deposition rate did not depend on the RF power as in Comparative Example 1-8, and when the μW power was 0.65 W / cm ³ or more. It was found that the SiH ₄ gas and the CH ₄ gas, which are the raw material gases, were completely decomposed by this electric power at a constant rate.
When the initial photoelectric conversion efficiency of the solar cell when irradiated with AM1.5 light was measured, the result showed the same tendency as in FIG.

That is, the power of μW is 10 times that of SiH ₄ gas.
At μW power (0.65 W / cm ³ ) or less for 0% decomposition,
It was also found that the initial photoelectric conversion efficiency was significantly improved when the RF power was higher than the μW power.

Comparative Example 1-11 When the i-type layer is formed in Example 1, the pressure inside the deposition chamber is 3 mTorr to 200 m.
Various non-single-crystal silicon carbide solar cells were manufactured under the same conditions as in Example 1 except that the conditions were changed to Torr.

When the initial photoelectric conversion efficiency of the solar cell when irradiated with AM1.5 light was measured, the results shown in FIG. 11 were obtained, and it was found that the initial photoelectric conversion efficiency was significantly reduced when the pressure was 50 mTorr or more. .

<Comparative Example 1-12> When the i-type Si layer was formed in Example 1, the deposition rate of the i-type Si layer was changed by changing the flow rate of the raw material gas SiH ₄ gas and the RF power to be introduced. Several different non-single crystal silicon carbide solar cells were prepared. The conditions other than the flow rate of SiH ₄ gas and RF power were the same as in Example 1.

When the initial photoelectric conversion efficiency of the solar cell when irradiated with light of AM1.5 was measured, the deposition rate was 2n.
It was found that the initial photoelectric conversion efficiency was significantly reduced at m / sec or more.

<Comparative Example 1-13> When forming the i-type Si layer in Example 1, several non-single-crystal silicon carbide solar cells having different i-type Si layer thicknesses were produced. The conditions other than the layer thickness of the i-type Si layer were the same as in Example 1.

When the initial photoelectric conversion efficiency of the solar cell when irradiated with AM1.5 light was measured, it was found that the initial photoelectric conversion efficiency was significantly reduced when the layer thickness of the i-type Si layer was 30 nm or more. It was

As described above, <Comparative Example 1-1> to <Comparative Example 1-1>
As is clear from 3>, the solar cell of this example (SC Ex 1) is the conventional solar cell (SC ratio 1-1) to (SC ratio 1).
It has been found that it has even better characteristics than -7),
It has been proved that at a pressure of 50 mTorr or less, excellent characteristics can be obtained without depending on manufacturing conditions such as a raw material gas flow rate and a substrate temperature.

Example 2 Similar to Example 1, the position of the minimum value of the band gap (Eg) in the layer thickness direction,
Several solar cells having different minimum values and different patterns were prepared, and their initial photoelectric conversion efficiency and durability characteristics were examined by the same method as in Example 1. At this time, SiH of the i-type layer
₄ except changing pattern of gas flow rate and CH ₄ gas flow rate was the same as in Example 1.

FIG. 12 shows a band diagram in the layer thickness direction of the solar cell when the change patterns of the SiH ₄ gas flow rate and the CH ₄ gas flow rate are changed. (SC Ex 2-1) to (SC Ex 2-
In 5), the position of the minimum value of the band gap in the layer thickness direction is changed, and from (SC Ex 2-1) to (SC Ex 2-
As it moves to 5), the position of the minimum value is moved from the p / i interface to n.
/ I interface. (SC Ex 2
-5) and (SC Ex 2-6) are obtained by changing the size of the minimum value of the band gap of (SC Ex 2-1).
(SC Ex 2-8) to (SC-Ex 2-10) are different band gap change patterns.

Table 3 shows the results obtained by examining the initial photoelectric conversion efficiency and durability characteristics of these solar cells produced. The values in the table are standardized based on (SC Ex 2-1).
As can be seen from these results, the band gap of the i-type layer changes smoothly in the layer thickness direction regardless of the magnitude of the minimum value of the band gap and the change pattern, and the position of the minimum value of the band gap is i. It was found that the solar cell of the present invention, which is offset from the central position of the mold layer in the p / i interface direction, is superior.

Example 3 A solar cell was produced in which B (boron) was contained in the i-type Si layer as a valence electron control agent serving as a donor. When forming the i-type Si layer, B ₂ H ₆ / H ₂ gas is added at 0.2 sccm in addition to SiH ₄ gas and H ₂ gas.
The solar cell of FIG. 1 was produced under the same conditions, the same method, and the same procedure as in Example 1 except that the solar cell was supplied.

The prepared solar cell (SC Ex 3) was similar to (SC Ex 1) in the conventional solar cells (SC ratio 1-1) to (SC Ex).
It was found that the initial photoelectric conversion efficiency and durability characteristics were better than those of the ratio 1-7).

Example 4 A solar cell was manufactured in which the stacking order of the n-type layer and the p-type layer was reversed. Table 4 shows the p-type layer, i-type layer,
The layer forming conditions for the i-type Si layer and the n-type layer will be described. The deposition rate of the i-type Si layer was 0.1 nm / sec. At the time of forming the i-type layer, the SiH ₄ gas flow rate and the CH ₄ gas flow rate were changed as shown in the pattern of FIG. 6 so that the minimum value of the bandgap comes from the p / i interface. The layers other than the semiconductor layer and the substrate were manufactured under the same conditions and the same method as in Example 1.

The produced solar cell (SC Ex 4) was similar to (SC Ex 1) in the conventional solar cells (SC ratio 1-1) to (SC Ex).
It was found that the initial photoelectric conversion efficiency and durability characteristics were better than those of the ratio 1-7).

Example 5 A non-single-crystal silicon carbide solar cell having a region having the maximum bandgap of the i-type layer on the p / i interface side and having a region thickness of 20 nm was produced.

FIG. 13-1 shows the flow rate change pattern of the i-type layer. Except for the i-type layer, the same conditions and methods as in Example 1 were used. 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 determined based on FIG. 7. The results shown in FIG. 13-2 were obtained. Became.

The prepared solar cell (SC Ex 5) is similar to (SC Ex 1) in the conventional solar cells (SC ratio 1-1) to (SC Ex).
It was found that the initial photoelectric conversion efficiency and durability characteristics were better than those of the ratio 1-7).

Comparative Example 5 Some non-single-crystal silicon carbide solar cells having a region having the maximum bandgap on the p / i interface side of the i-type layer and varying the thickness of the region were manufactured. did. Except for the thickness of the region, the same conditions and methods as in Example 5 were used.

When the initial photoelectric conversion efficiency and durability characteristics of the solar cell produced were measured, when the region thickness was 1 nm or more and 30 nm or less, the initial photoelectric conversion was better than that of the solar cell of Example 1 (SC Ex 1). Efficiency and durability characteristics were obtained.

Example 6 A non-single-crystal silicon carbide solar cell having a region having the maximum bandgap of the i-type layer near the n / i interface and having a thickness of 15 nm was produced. FIG. 13-13 shows the flow rate change pattern of the i-type layer. Except for the i-type layer, the same conditions and methods as in Example 1 were used. 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 of the i-type layer in the layer thickness direction was examined based on FIG. 7. The results shown in FIG. 13-4 were obtained. Became.

The prepared solar cell (SC Ex 6) is similar to (SC Ex 1) in the conventional solar cells (SC ratio 1-1) to (SC Ex).
It was found that the initial photoelectric conversion efficiency and durability characteristics were better than those of the ratio 1-7).

<Comparative Example 6> A region having a maximum bandgap value was formed in the vicinity of the n / i interface of the i-type layer, and several non-single-crystal silicon carbide solar cells having various thicknesses were prepared. did. It was manufactured using the same conditions and the same method as in Example 6 except for the thickness of the region.

When the initial photoelectric conversion, conversion efficiency, and durability characteristics of the manufactured solar cell were measured, the solar cell of Example 1 (SC Ex 1) was observed when the region thickness was 1 nm or more and 30 nm or less.
Even better initial photoelectric conversion efficiency and durability characteristics were obtained.

Example 7 Example 1 was repeated except that the μW electric power was changed as shown in FIG. 14 when forming the i-type layer.
Same conditions, same method, same procedure were used. The i-type layer of the manufactured solar cell (SC Ex 7) had a layer thickness of 340 nm, and similar to (SC Ex 1), the conventional solar cell (SC ratio 1-
It was found that the initial photoelectric conversion efficiency and durability characteristics were better than those of 1) to (SC ratio 1-7).

Example 8 A non-single crystal silicon carbide solar cell having an i-type layer containing oxygen atoms was produced. When forming the i-type layer, in addition to the gas flowing in Example 1, O ₂ / H
The same conditions, the same method, and the same procedure as in Example 1 were used except that e gas was introduced into the deposition chamber 401 at 10 sccm.
The produced solar cell (SC Ex 8) is the same as (SC Ex 1)
It was found that the solar cells had better initial photoelectric conversion efficiency and durability characteristics than the conventional solar cells (SC ratio 1-1) to (SC ratio 1-7).

Further, when the content of oxygen atoms in the i-type layer was examined by a secondary ion mass spectrometer (SIMS), it was found that they were almost uniformly contained and 2 × 10 ¹⁹ (pieces / cm ³ ). Do you get it.

Example 9 A non-single-crystal silicon carbide solar cell having a nitrogen atom in the i-type layer was produced. When forming the i-type layer, in addition to the gas flowing in Example 1, NH ₃ /
The same conditions, the same method, and the same procedure as in Example 1 were used except that H ₂ gas was introduced into the deposition chamber 401 at 5 sccm.
The produced solar cell (SC Ex 9) is the same as (SC Ex 1)
It was found that the solar cells had better initial photoelectric conversion efficiency and durability characteristics than the conventional solar cells (SC ratio 1-1) to (SC ratio 1-7).

Further, the content of nitrogen atoms in the i-type layer is adjusted to SI
When examined by MS, it was found that the content was almost uniform and 3 × 10 ¹⁷
It was found to be (pieces / cm ³ ).

Example 10 A non-single crystal silicon carbide solar cell having an i-type layer containing oxygen atoms and nitrogen atoms was produced. When the i-type layer is formed, the same conditions as in Example 1 except that O ₂ / He gas is 5 sccm, NH ₃ / H ₂ gas is 5 sccm, and is introduced into the deposition chamber 401 in addition to the gas flowing in Example 1. , Same method, same procedure.

The prepared solar cell (SC Ex 10) was
Like the actual 1), the conventional solar cells (SC ratio 1-1) to (S
It was found that the initial photoelectric conversion efficiency and durability characteristics were better than those of C ratio 1-7). Moreover, when the contents of oxygen atoms and nitrogen atoms in the i-type layer were examined by SIMS, they were found to be contained almost uniformly, and each was 1 × 10 ¹⁹ (pieces /
It was found to be 3 cm ³ ), 3 × 10 ¹⁷ (pieces / cm ³ ).

Example 11 A non-single-crystal silicon carbide solar cell in which the hydrogen content of the i-type layer was changed according to the silicon content was produced. O ₂ / He gas cylinder with SiF ₄
When replacing the gas (purity 99.999%) cylinder and forming the i-type layer, according to the flow rate pattern of FIG.
The flow rates of H ₄ gas, CH ₄ gas, and SiF ₄ gas were changed. This solar cell (SC
The change in the band gap in the layer thickness direction of Ex 11) was obtained.
It is shown in FIG. 15-2. Further, SIMS was used to analyze the content of hydrogen atoms and silicon atoms in the layer thickness direction.
As a result, as shown in FIG. 15-3, it was found that hydrogen atoms have a layer thickness direction distribution corresponding to silicon atoms.

When the initial photoelectric conversion efficiency and durability characteristics of this solar cell (SC Ex 11) were obtained, similar to the solar cell of Example 1, conventional solar cells (SC ratio 1-1) to (SC ratio 1) were obtained.
It was found that the initial photoelectric conversion efficiency and durability characteristics were better than those of -7).

Example 12 When a semiconductor layer of the non-single crystal silicon carbide solar cell of FIG. 1 is formed by the manufacturing apparatus using the microwave plasma CVD method shown in FIG. 4, a silicon atom-containing gas (SiH ₄ gas) is used. ) And a carbon atom-containing gas (CH ₄ gas) were mixed at a distance of 1 m from the deposition chamber to manufacture a non-single-crystal silicon carbide solar cell (SC Ex 12) by the same method and the same procedure as in Example 1.

The manufactured solar cell (SC Ex 12) has (SC
It was found that the initial photoelectric conversion efficiency and durability characteristics were better than those of Ex 1).

Example 13 A tandem solar cell having a non-single-crystal silicon carbide semiconductor layer shown in FIG. 16 was manufactured using the manufacturing apparatus of FIG. 4 using the microwave plasma CVD method of the present invention. . First, a substrate was manufactured.
As in Example 1, a 50 × 50 mm ² stainless steel substrate was ultrasonically cleaned with acetone and isopropanol and dried.

A 0.3 μm Ag (silver) reflective layer was formed on the surface of the stainless steel substrate by the sputtering method. At this time, the substrate temperature was set to 350 ° C., and the substrate surface was made uneven (textured). Substrate temperature 35
A ZnO (zinc oxide) reflection enhancing layer of 1.0 μm was formed at 0 ° C.

First, preparation for film formation was completed by the same method and procedure as in Example 1. The first n-type layer is formed on the substrate by the same procedure and the same method as in Example 1, and the first i-type layer, the first p-type layer, the second n-type layer, and the i-type Si are further formed. A layer, a second i-type layer, and a second p-type layer were sequentially formed. When forming the second i-type layer, S is formed according to the flow rate change pattern as shown in FIG.
The iH ₄ gas flow rate and the CH ₄ gas flow rate were changed to form the i-type Si layer at a deposition rate of 0.15 nm / sec.

Next, as in Example 1, ITO (In ₂ O ₃ +) having a layer thickness of 80 nm was formed as a transparent electrode on the second p-type layer.
SnO ₂ ), and then chromium (Cr) having a layer thickness of 10 μm was vapor-deposited by a usual vacuum vapor-deposition method as a collector electrode. Thus, the production of the tandem solar cell using the microwave plasma CVD method is completed.

This solar cell is referred to as (SC Ex 13), and the manufacturing conditions of each semiconductor layer are shown in Table 5.

<Comparative Example 13-1> When the second i-type layer of FIG. 16 is formed, Si is formed in accordance with the flow rate change pattern of FIG.
A tandem solar cell was produced by the same method and procedure as in Example 13 except that the H ₄ gas flow rate and the CH ₄ gas flow rate were changed. This solar cell will be called (SC ratio 13-1).

<Comparative Example 13-2> In forming the second i-type layer shown in FIG. 16, the tandem method and the procedure are the same as those of Example 13 except that the μW power is set to 0.5 W / cm ^3. Type solar cell was produced. This solar cell (SC ratio 13-2)
I will call it.

<Comparative Example 13-3> In forming the second i-type layer shown in FIG. 16, the tandem method and tandem were the same as those of Example 13 except that the RF power was 0.15 W / cm ^3. Type solar cell was produced. This solar cell (SC ratio 13-
3).

<Comparative Example 13-4> Example 13 was repeated except that when the second i-type layer shown in FIG. 16 was formed, the μW power was 0.5 W / cm ³ and the RF power was 0.2 W / cm ^3. A tandem solar cell was produced by the same method and the same procedure. This solar cell will be referred to as (SC ratio 13-4).

<Comparative Example 13-5> A tandem method and a procedure similar to those of Example 13 were applied except that the pressure in the deposition chamber 401 was set to 0.1 Torr when the second i-type layer shown in FIG. 16 was formed. Type solar cell was produced. This solar cell (SC ratio 1
3-5).

<Comparative Example 13-6> A tandem solar cell was produced by the same method and procedure as in Example 13 except that the deposition rate was 3 nm / sec when the i-type Si layer shown in FIG. 16 was formed. did. This solar cell will be referred to as (SC ratio 1316).

<Comparative Example 13-7> A tandem solar cell was produced by the same method and procedure as in Example 13, except that the thickness of the i-type Si layer shown in FIG. 16 was 40 nm. This solar cell is called (SC ratio 1317).

The initial photoelectric conversion efficiency and durability characteristics of these tandem solar cells produced were measured in the same manner as in Example 1. ) To (SC ratio 13-7), the initial photoelectric conversion efficiency and durability characteristics were found to be better.

Example 14 Using the manufacturing apparatus of FIG. 4 using the microwave plasma CVD method of the present invention, the triple type solar cell of FIG. 17 having a non-single crystal silicon carbide semiconductor layer was manufactured. First, a substrate was manufactured. As in Example 1, a 50 × 50 mm ² stainless steel substrate was ultrasonically cleaned with acetone and isopropanol and dried.
Using a sputtering method as in Example 13, Ag of 0.3 μm was formed on the surface of the stainless steel substrate at a substrate temperature of 350 ° C.
A (silver) reflective layer was formed to make the surface of the substrate uneven (textured). On top of that, at a substrate temperature of 350 ° C, 1.0 μm
ZnO (zinc oxide) reflection enhancing layer was formed.

First, in place of the NH ₃ / H ₂ gas cylinder, G
An eH ₄ gas (purity 99.999%) cylinder was connected, and the preparation for film formation was completed by the same method and procedure as in Example 1.
A first n-th layer is formed on the substrate by the same procedure and method as in the first embodiment.
A first i-type layer, a first p-type layer, a second n-type layer, a second i-type layer, a second p-type layer, a third n-type layer, i. A type Si layer, a third i-type layer, and a third p-type layer were sequentially formed. When forming the third i-type layer, the SiH ₄ gas flow rate and the CH ₄ gas flow rate are changed according to the flow rate change pattern as shown in FIG. 5, and the i-type Si layer has a flow rate of 0.15 nm / sec.
Formed at a deposition rate of.

Then, in the same manner as in Example 1, ITO (In _{2) having a} layer thickness of 80 nm was formed as a transparent electrode on the third p-type layer.
O ₃ + SnO ₂ ) followed by a collector electrode having a layer thickness of 10 μm
Chromium (Cr) was deposited by a normal vacuum deposition method. As described above, the production of the triple solar cell using the microwave plasma CVD method is completed.

This solar cell is referred to as (SC Ex 14), and the manufacturing conditions of each semiconductor layer are shown in Table 6.

<Comparative Example 14-1> When the third i-type layer of FIG. 17 is formed, Si is formed in accordance with the flow rate change pattern of FIG.
A triple type solar cell was produced by the same method and the same procedure as in Example 14 except that the H ₄ gas flow rate and the CH ₄ gas flow rate were changed. This solar cell will be called (SC ratio 14-1).

<Comparative Example 14-2> When the third i-type layer shown in FIG. 17 was formed, a triplet was formed in the same manner as in Example 14 except that the μW power was changed to 0.5 W / cm ^3. Type solar cell was produced. This solar cell (SC ratio 14-2)
I will call it.

<Comparative Example 14-3> When the third i-type layer shown in FIG. 17 was formed, a triplet was prepared in the same manner as in Example 14 except that the RF power was set to 0.15 W / cm ^3. Type solar cell was produced. This solar cell (SC ratio 14-
3).

[0241] <Comparative Example 14-4> forming the third 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 manufactured by the same method and the same procedure. This solar cell will be called (SC ratio 14-4).

<Comparative Example 14-5> When the third i-type layer shown in FIG. 17 is formed, the pressure in the deposition chamber 401 is set to 0.08 Torr.
A triple type solar cell was manufactured by the same method and procedure as in Example 14 except that the above was used. This solar cell is called (SC ratio 14-5).

<Comparative Example 14-6> A tandem solar cell was manufactured by the same method and procedure as in Example 14 except that the deposition rate was 3 nm / sec when the i-type Si layer shown in FIG. 17 was formed. did. This solar cell is called (SC ratio 14-6).

Comparative Example 14-7 A triple solar cell was manufactured by the same method and procedure as in Example 14, except that the i-type Si layer shown in FIG. 17 was formed with a layer thickness of 40 nm. This solar cell will be called (SC ratio 14-7>).

The initial photoelectric conversion efficiency and durability characteristics of these produced triple type solar cells were measured by the same method as in Example 1. As a result, (SC Ex. 14) was the same as the conventional triple type solar cell (SC ratio 14-1). ) To (SC ratio 14-7), the initial photoelectric conversion efficiency and durability were better.

Example 15 Using the manufacturing apparatus of FIG. 4 which uses the microwave plasma CVD method of the present invention, FIG.
We produced a triple-type solar cell of, made it into a module, and applied it to a power generation system. 65 triple-type solar cells (SC Ex 14) of 50 × 50 mm ² were prepared under the same conditions, the same method, and the same procedure as in Example 14. EVA (ethylene vinyl acetate) on a 5.0 mm thick aluminum plate
An adhesive sheet made of was placed on top of this, a nylon sheet was placed on top of it, and the solar cells prepared on top of that 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. This module (MJ real 1
5). The initial photoelectric conversion efficiency of the manufactured module was measured by the same method as in Example 1.

The manufactured module was connected to the circuit of the power generation system shown in FIG. An external light that lights at night was used as the load. The whole system was operated by the storage battery and the power of the module, and the module was installed at the angle that could collect the most sunlight. The photoelectric conversion efficiency after one year was measured, and the photodegradation rate (photoelectric conversion efficiency after one year / initial photoelectric conversion efficiency) was obtained.

Comparative Example 15-1 Sixty-five conventional triple solar cells (SC ratio 14-X) (X: 1 to 7) were prepared and modularized in the same manner as in Example 15. This module is called (MJ ratio 15-X). The initial photoelectric conversion efficiency and the photoelectric conversion efficiency after one year passed were measured under the same conditions, the same method, and the same procedure as in Example 15, and the photodegradation rate was obtained. The optical deterioration rate of (MJ ratio 15-X) is (MJ actual 1
The results are as follows for 5).

[0250] From the above results, it was found that the solar cell module of this example has a better light deterioration resistance property than the conventional solar cell module.

Example 16 When a solar cell was manufactured in the same manner as in Example 14, the triple plasma shown in FIG. 19 having a second i-type Si layer was formed at the p / i interface by using the RF plasma CVD method. Type solar cell was produced. A first n-type layer was formed on the substrate by the same method as in Example 14, and further a first i-type layer, a first p-type layer, a second n-type layer, a second i-type layer, Second
P-type layer, third n-type layer, first i-type Si layer, third i-type layer
The mold layer, the second i-type Si layer, and the third p-type layer were sequentially formed. When forming the third i-type layer, the SiH ₄ gas flow rate and the CH ₄ gas flow rate were changed according to the flow rate change pattern as shown in FIG. 13-1. When forming the first i-type Si layer and the second i-type Si layer, the deposition rate is 0.15 nm / sec.
So that

Then, similarly to Example 1, ITO (In ₂ O ₃ +) having a layer thickness of 80 nm was formed as a transparent electrode on the third p-type layer.
SnO ₂ ) and chromium (Cr) having a layer thickness of 10 μm as a collector electrode were deposited by a normal vacuum deposition method. As described above, the production of the triple solar cell using the microwave plasma CVD method is completed. This solar cell is called (SC Ex 16), and the manufacturing conditions of each semiconductor layer are shown in Table 7.

When the initial photoelectric conversion efficiency and durability characteristics of the produced triple solar cell of FIG. 19 were measured by the same method as in Example 1, (SC Ex 16) showed that the conventional triple solar cell (SC ratio 14- It was found that the initial photoelectric conversion efficiency and durability characteristics were better than those of 1) to (SC ratio 14-7).

Example 17 When the solar cell of FIG. 19 is manufactured in the same manner as in Example 16, the i-type Si layer (first i-type Si layer) formed at the n / i interface is not used. , P / i
The triple type solar cell of FIG. 19 in which the i-type Si layer (second i-type Si layer) formed at the interface has a larger layer thickness was produced.

A first n-type layer was formed on the substrate by the same method, procedure and conditions as in Example 16 except that the thickness of the second i-type Si layer was 20 nm, and the first i-type layer was formed. Layer, first p
Type layer, second n-type layer, second i-type layer, second p-type layer, third n-type layer, first i-type Si layer, third i-type layer, second i-type layer A type Si layer and a third p-type layer were sequentially formed.

Then, as in Example 1, ITO (In ₂ O ₃ +) having a layer thickness of 80 nm was formed as a transparent electrode on the third p-type layer.
SnO ₂ ) and chromium (Cr) having a layer thickness of 10 μm as a collector electrode were deposited by a normal vacuum deposition method. As described above, the production of the triple solar cell using the microwave plasma CVD method is completed. This solar cell will be called (SC Ex 17).

The initial photoelectric conversion efficiency and durability characteristics of the produced triple-type solar cell of FIG. 19 were measured by the same method as in Example 16. As a result, (SC Ex. 17) was obtained from the triple solar cell of (SC Ex. 16). It has been found that also has a better initial photoelectric conversion efficiency and durability characteristics.

Example 18 In this example, the solar cell of FIG. 1 having a laminated structure of p-type layers was produced.

First, a substrate was manufactured. 50 × 50m
The m ² stainless steel substrate was ultrasonically cleaned with acetone and isopropanol and dried. Ag with a layer thickness of 0.3 μm on a stainless steel substrate surface at room temperature using a sputtering method.
A reflection layer of (silver) and a reflection-increasing layer of ZnO (zinc oxide) having a layer thickness of 1.0 μm at 350 ° C. were formed on the reflection layer.

Next, the source gas supply device 200 shown in FIG.
0 and a deposition apparatus 400 using a glow discharge decomposition method to manufacture a semiconductor layer on the reflection increasing layer.

After preparation for film formation was completed in the same manner as in Example 1, an n-type layer, an i-type Si layer, an i-type layer, and
A p-type semiconductor layer was manufactured. The SiH ₄ gas and the CH ₄ gas were mixed at a position m from the deposition chamber.

To prepare the n-type layer, the auxiliary valve 40
8. The valve 2003 is gradually opened, H ₂ gas is introduced into the deposition chamber 401 through the gas introduction pipe 411, the mass flow controller 2013 is set so that the H ₂ gas flow rate is 50 sccm, and the pressure in the deposition chamber is set to 1 .0 Tor
The conductance valve was adjusted while observing the vacuum gauge 402 so as to be r, and the heater 405 was set so that the temperature of the substrate 404 became 350 ° C. When the substrate is sufficiently heated, the valves 2001 and 2004 are gradually opened to add SiH ₄ gas and PH ₃ / H ₂ gas to the deposition chamber 40.
It was made to flow into 1. At this time, the SiH ₄ gas flow rate is 2 sc
cm, H ₂ gas flow rate was 100 sccm, and PH ₃ / H ₂ gas flow rate was adjusted to 20 sccm by mass flow controllers 2011, 2013, and 2014, respectively.
The opening of the conductance valve 407 was adjusted while observing the vacuum gauge 402 so that the pressure in the deposition chamber 401 was 1.0 Torr. After confirming that the shutter 415 was closed, the power of the RF power source was set to 0.007 W / cm ³ , and the RF power was introduced to the RF electrode 410 to cause glow discharge. Open the shutter and press n on the substrate 404.
The formation of the mold layer was started, and when the n-type layer having a layer thickness of 20 nm was prepared, the shutter was closed, the RF power was turned off, the glow discharge was stopped, and the formation of the n-type layer was completed. Valve 2001,
2004 is closed and SiH ₄ gas in the deposition chamber 401 is
Stopping the flow of PH ₃ / H ₂ gas for 5 minutes, after which continued to flow H ₂ gas into the deposition chamber 401, closing the outflow valves 2003, it was evacuated deposition chamber 401 and the gas pipes.

Next, to form an i-type Si layer, the valve 2003 is gradually opened, H ₂ gas is introduced into the deposition chamber 401, and the mass flow controller 2013 is used so that the H ₂ gas flow rate becomes 50 sccm. I adjusted. The conductance valve was adjusted while observing the vacuum gauge 402 so that the pressure in the deposition chamber was 1.5 Torr. The heater 405 is set so that the temperature of the substrate 404 becomes 250 ° C., and when the substrate is sufficiently heated, the valve 200 is further added.
1 was gradually opened, and SiH ₄ gas was caused to flow into the deposition chamber 401. At this time, the SiH ₄ gas flow rate is ₂ sccm, H ₂
Each mass flow controller adjusted the gas flow rate to 100 sccm.

The pressure in the deposition chamber 401 is 1.5 Torr.
The opening of the conductance valve 407 was adjusted while observing the vacuum gauge 402 so that RF power supply 0.007W
/ Cm ³ , set RF power, introduce glow discharge, open shutter 415, 0.1 nm / sec
The formation of the i-type Si layer on the n-type layer was started at the deposition rate of. When the i-type Si layer having a layer thickness of 20 nm was prepared, the shutter was closed, the RF power was turned off, the glow discharge was stopped, and the i
The formation of the mold Si layer was completed. The valve 2001 is closed to stop the flow of SiH ₄ gas into the deposition chamber 401 for 5 minutes.
After continuously flowing H ₂ gas into the deposition chamber 401, the valve 2
003 was closed, and the inside of the deposition chamber 401 and the inside of the gas pipe were evacuated.

Next, to prepare the 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. Adjusting the conductance valve while watching the vacuum gauge 402 so that the pressure in the deposition chamber is 0.01 Torr, and setting the heater 405 so that the temperature of the substrate 404 becomes 350 ° C.
When the substrate is sufficiently heated, the valve 2001,
2002 was gradually opened, and SiH ₄ gas and CH ₄ gas were caused to flow into the deposition chamber 401. At this time, the mass flow controllers were adjusted so that the SiH ₄ gas flow rate was 100 sccm, the CH ₄ gas flow rate was 30 sccm, and the H ₂ gas flow rate was 300 sccm. The pressure in the deposition chamber 401 is
The opening of the conductance valve 407 was adjusted while observing the vacuum gauge 402 so as to be 0.01 Torr. next,
Set the power of the RF power source 403 to 0.40 W / cm ³ ,
It was applied to the RF electrode 410. After that, the power of the μW power source (not shown) is set to 0.20 W / cm ³ , and the dielectric window 413 is set.
ΜW electric power was introduced into the deposition chamber 401 to generate glow discharge, the shutter was closed, and the production of the i-type layer on the i-type Si layer was started. Using the computer connected to the mass flow controller, the flow rate of SiH ₄ gas and CH ₄ gas was changed according to the flow rate change pattern shown in FIG. 5, and when the i-type layer with a layer thickness of 300 nm was produced, the shutter was closed and the μW power supply To turn off the glow discharge,
The F power supply 403 was turned off, and the production of the i-type layer was completed. Valve 2
001 and 2002 are closed, and SiH enters the deposition chamber 401.
Stop the inflow of ₄ gas and CH ₄ gas for 5 minutes, deposition chamber 401
After continuing to flow H ₂ gas into the inside, close the valve 2003,
The deposition chamber 401 and the gas pipe were evacuated.

[0266] To produce a p-type layer, the valve 2003 was gradually opened, introducing H ₂ gas into the deposition chamber 401, H ₂
The mass flow controller 2013 adjusted the gas flow rate to 300 sccm. The pressure in the deposition chamber is 0.
It was adjusted with a conductance valve while watching the vacuum gauge 402 so as to be 01 Torr. The temperature of the substrate 404 is 20
The heater 405 is set to 0 ° C., and when the substrate is sufficiently heated, the valves 2001 and 200 are further added.
2, 2005 was gradually opened, and SiH ₄ gas, CH ₄ gas, H ₂ gas, and B ₂ H ₆ / H ₂ gas were caused to flow into the deposition chamber 401. At this time, SiH ₄ gas flow rate is 10 sccm, C
H ₄ gas flow rate is 5 sccm, H ₂ gas flow rate is 300 sccc
m and B ₂ H ₆ / H ₂ gas flow rate was adjusted to 10 sccm by each mass flow controller. Deposition chamber 4
The pressure inside 01 was adjusted to 0.02 Torr by adjusting the opening of the conductance valve 407 while watching the vacuum gauge 402. The power of the μW power source was set to 0.30 W / cm ³ , and μW power was introduced into the deposition chamber 401 through the dielectric window 413 to cause glow discharge, the shutter 415 was opened, and the light-doped layer was formed on the i-type layer. The formation of this layer (referred to as layer B) was started. When the B layer having a layer thickness of about 3 nm was prepared, the shutter was closed and the μW power was turned off.
The glow discharge was stopped. Valves 2001, 2002, 20
05 is closed, and SiH ₄ gas and CH ₄ are introduced into the deposition chamber 401.
The flow of the gas, B ₂ H ₆ / H ₂ gas was stopped, and the H ₂ gas was continuously flowed into the deposition chamber 401 for 5 minutes, and then the valve 2003
Was closed, and the inside of the deposition chamber 401 and the inside of the gas pipe were evacuated.

Next, the valve 2005 is gradually opened to allow the B ₂ H ₆ / H ₂ gas to flow into the deposition chamber 401 at a flow rate of 10
It was adjusted with the Maslow controller so that it would be 00 sccm. Adjusting the conductance valve while watching the vacuum gauge 402 so that the pressure in the deposition chamber is 0.02 Torr, the power of the μW power source is set to 0.20 W / cm ³ , and the μW power is fed into the deposition chamber 401 through the dielectric window 413. Introduce electric power, cause glow discharge, open the shutter 415,
The formation of a layer of boron (B) (which layer will be referred to as A layer) was started on the B layer. After 6 seconds, the shutter was closed, the μW power supply was turned off, and the glow discharge was stopped.
The valve 2005 is closed and B ₂ H ₆ /
Stopping the flow of H ₂ gas for 5 minutes, after which continued to flow H ₂ gas into the deposition chamber 401, closing the valve 2003, the deposition chamber 4
The inside of 01 and the inside of the gas pipe were evacuated.

Then, the same method, the same procedure as the above-mentioned method,
Under the same conditions, a B layer, an A layer, and a B layer were sequentially formed on the A layer, and the formation of a p-type layer having a layer thickness of about 10 nm was completed.

The auxiliary valve 408 is closed and the leak valve 4
09 was opened, and the deposition chamber 401 was leaked.

Next, on the p-type layer, a layer thickness of 8 was formed as a transparent electrode.
0 nm ITO (In₂O₃+ Sn0 ₂) And a collector electrode
Then, chromium (Cr) with a layer thickness of 10 μm is formed by a normal vacuum deposition method.
It was deposited at.

Thus, the production of the non-single crystal silicon carbide solar cell was completed. This solar cell is referred to as (SC Ex 18), and Table 8 shows the conditions for forming the n-type layer, the i-type Si layer, the i-type layer, and the p-type layer.

Comparative Example 18-1 Example 18 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 pattern shown in FIG. 6 when forming the i-type layer. Under the same conditions and the same procedure as above, a reflection layer, a reflection enhancement layer, an n-type layer, and an i-type Si were formed on the substrate
A layer, an i-type layer, a p-type layer, a transparent electrode, and a collector electrode were formed to produce a solar cell. This solar cell (SC ratio 18-1)
I will call it.

<Comparative Example 18-2> When a i-type layer was formed, the reflective layer was formed on the substrate under the same conditions and the same procedure as in Example 18, except that the μW power was 0.5 W / cm ^3. A reflection increasing layer, an n-type layer, an i-type Si layer, an i-type layer, a p-type layer, a transparent electrode, and a collector electrode were formed to fabricate a solar cell. This solar cell will be referred to as (SC ratio 18-2).

<Comparative Example 18-3> A reflective layer was formed on a substrate under the same conditions and the same procedure as in Example 18, except that the RF power was 0.15 W / cm ³ when forming the i-type layer. A reflection increasing layer, an n-type layer, an i-type Si layer, an i-type layer, a p-type layer, a transparent electrode, and a collector electrode were formed to fabricate a solar cell. This solar cell will be called (SC ratio 18-3).

Comparative Example 18-4 When forming the i-type layer, μW power was 0.5 W / cm ³ , and RF power was 0.55.
A reflective layer, a reflection-increasing layer, an n-type layer, an i-type Si layer, an i-type layer, a p-type layer, and a transparent electrode were formed on the substrate under the same conditions and the same procedure as in Example 18 except that W / cm ³ was used. Then, a collector electrode was formed to produce a solar cell. This solar cell (SC ratio 18-
4).

Comparative Example 18-5 Example 18 was repeated except that the internal pressure was set to 0.08 Torr when forming the i-type layer.
Under the same conditions and the same procedure as above, on the substrate, a reflection layer, a reflection increasing layer, an n-type layer, an i-type Si layer, an i-type layer, a p-type layer, a transparent electrode,
A collector electrode was formed to produce a solar cell. This solar cell will be called (SC ratio 18-5).

<Comparative Example 18-6> Example 1 was repeated except that the deposition rate was set to 3 nm / sec when the i-type Si layer was formed.
A solar cell is formed by forming a reflective layer, a reflection increasing layer, an n-type layer, an i-type Si layer, an i-type layer, a p-type layer, a transparent electrode, and a current collecting electrode on a substrate under the same conditions and the same procedure as in 8. It was made. This solar cell will be called (SC ratio 18-6).

<Comparative Example 18-7> When the i-type Si layer was formed, a reflective layer, a reflection increasing layer, and a reflective layer were formed on the substrate under the same conditions and the same procedure as in Example 18, except that the layer thickness was 40 nm. A solar cell was produced by forming an n-type layer, an i-type Si layer, an i-type layer, a p-type layer, a transparent electrode, and a collector electrode. This solar cell (SC
Ratio 18-7).

The manufactured solar cells (SC Ex 18) and (S
The initial photoelectric conversion efficiency (photovoltaic power / incident light power) and durability characteristics of C ratio 18-1) to (SC ratio 18-7) were measured. The initial photoelectric conversion efficiency is
Installed under -1.5 (100 mW / cm ² ) light irradiation,
The VI characteristic was measured and determined.

As a result of the measurement, it was found that the solar cell of this example (SC Ex 18) had an initial photoelectric conversion efficiency improved by 1.011 times as compared with the solar cell of Example 1 (SC Ex 1).

For the solar cell of (SC Ex 18), the photoelectric conversion efficiencies of (SC ratio 18-1) to (SC ratio 18-7) were as follows.

(SC ratio 18-1) 0.78 times (SC ratio 18-2) 0.63 times (SC ratio 18-3) 0.80 times (SC ratio 18-4) 0.65 times (SC ratio 18-5) 0.77 times (SC ratio 18-6) 0.82 times (SC ratio 18-7) 0.86 times The durability characteristics were measured by measuring the prepared solar cell at a humidity of 70%,
Installed in a dark place with a temperature of 60 ° C, amplitude 1m at 3600 rpm
AM1.5 (100 m after applying vibration of m for 24 hours
W / cm ² ) The decrease in photoelectric conversion efficiency under irradiation (photoelectric conversion efficiency after durability test / initial photoelectric conversion efficiency) was performed.

As a result of the measurement, it was found that the solar cell of this example (SC Ex. 18) was improved in durability by 1.012 times as compared with the solar cell of Example 1 (SC Ex. 1).

For the (SC Ex 18) solar cell, the decrease in photoelectric conversion efficiency for (SC ratio 18-1) to (SC ratio 18-7) was as follows.

(SC ratio 18-1) 0.79 times (SC ratio 18-2) 0.71 times (SC ratio 18-3) 0.78 times (SC ratio 18-4) 0.70 times (SC ratio 18-5) 0.72 times (SC ratio 18-6) 0.83 times (SC ratio 18-7) 0.89 times Next, a p-type layer is formed on the silicon substrate (111),
The cross-sectional TEM (transmission electron microscope) image was observed. A
A p-type layer was formed on a silicon substrate by the same method and procedure as in Example 18, except that the layer deposition time was 12 seconds. When the produced sample was cut in the cross-sectional direction and the state of lamination of the A layer and the B layer in the p-type layer was observed, the layer thickness was about 1 as shown in FIG.
It was found that the A layer having a thickness of 3 nm and the B layer having a thickness of about 3 nm were alternately laminated.

Comparative Example 18-8 A non-single crystal carbonization was carried out under the same conditions as in Example 18 except that the μW power and RF power introduced when forming the i-type layer in Example 18 were variously changed. Several silicon solar cells were produced. RF deposition rate
It was found that the μW power became constant at 0.32 W / cm ³ or more without depending on the power, and the SiH ₄ gas and the CH ₄ gas that were the raw material gases were 100% decomposed by this power.

When the initial photoelectric conversion efficiency of the solar cell when irradiated with AM1.5 (100 mW / cm ² ) light was measured, the μW power was 100% for SiH ₄ gas and CH ₄ gas.
It was found that the initial photoelectric conversion efficiency was significantly improved when the μW power (% 0.32 W / cm ³ ) for% decomposition and the RF power was higher than the μW power.

<Comparative Example 18-9> When the i-type layer is formed in Example 18, the flow rate of the gas introduced into the deposition chamber 401 is set to Si.
H ₄ gas was changed to 50 sccm and CH ₄ gas was changed to 10 sccm, H ₂ gas was not introduced, and μW electric power and RF electric power were variously changed to manufacture some non-single-crystal silicon carbide solar cells. Other conditions were the same as in Example 18. Deposition rate and μ
When the relationship between W power and RF power was examined, Comparative Example 18-
Similar to 8, the deposition rate does not depend on the RF power, and is constant when the μw power is 0.18 W / cm ³ or more, and at this μW power,
100% of SiH ₄ gas and CH ₄ gas which are raw material gases
It turned out to be disassembled.

When the initial photoelectric conversion efficiency of the solar cell when irradiated with AM1.5 light was measured, the result showed the same tendency as in FIG. That is, the μW power is SiH ₄
It was found that the initial photoelectric conversion efficiency was significantly improved when the power of the gas and the CH ₄ gas was 100% decomposed at μW power (0.18 W / cm ³ ) or less and the RF power was higher than the μW power.

<Comparative Example 18-10> When the i-type layer is formed in Example 18, the flow rate of the gas introduced into the deposition chamber 401 is S.
iH ₄ gas 200 sccm, CH ₄ gas 50 sccm, H
Change to ₂ gas 500sccm, and the substrate temperature is 30
Several non-single crystal silicon carbide solar cells were prepared by changing the setting of the heater so that the temperature was 0 ° C. and variously changing the μW power and the RF power. Other conditions were the same as in Example 18. 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 as in Comparative Example 18-8, and the μW power was constant at 0.65 W / cm ³ or more, With this electric power, SiH ₄ gas and CH ₄ which are raw material gases
It was found that the gas was 100% decomposed. AM
When the initial photoelectric conversion efficiency of the solar cell when irradiated with 1.5 light was measured, it showed the same tendency as in FIG. 10, and the μW power decomposed 100% of SiH ₄ gas.
It was found that the initial photoelectric conversion efficiency was significantly improved when the RF power was 5 W / cm ³ ) or less and the RF power was higher than the μW power.

<Comparative Example 18-11> When the i-type layer was formed in Example 18, the pressure in the deposition chamber was changed from 3 mTorr to 20.
Various changes were made up to 0 mTorr, and other conditions were in Example 18.
Several non-single crystal silicon carbide solar cells were prepared in the same manner as in.

When the initial photoelectric conversion efficiency of the solar cell when irradiated with AM1.5 light was measured, the pressure was 50 mTo
It was found that the initial photoelectric conversion efficiency was significantly reduced above rr.

<Comparative Example 18-12> In Example 18, the i-type S was used.
When forming the i layer, several non-single-crystal silicon carbide solar cells were manufactured in which the flow rate of the SiH ₄ gas as the source gas and the RF power to be introduced were variously changed to change the deposition rate of the i-type Si layer. The conditions other than the flow rate of SiH ₄ gas and RF power were the same as in Example 18.

When the initial photoelectric conversion efficiency of the solar cell when irradiated with light of AM1.5 was measured, the deposition rate was 2n.
It was found that the initial photoelectric conversion efficiency was significantly reduced at m / sec or more.

<Comparative Example 18-13> In Example 18, the i-type S was used.
When forming the i layer, some non-single-crystal silicon carbide intestine batteries having different thicknesses of the i-type Si layer were manufactured. The conditions other than the layer thickness of the i-type Si layer were the same as in Example 18. AM1.5
When the initial photoelectric conversion efficiency of the solar cell when irradiated with light was measured, it was found that the initial photoelectric conversion efficiency was significantly reduced when the layer thickness of the i-type Si layer was 30 nm or more.

As described above, <Comparative example 18-1> to <Comparative example 18>
As is clear from -13>, the solar cell of the present invention (SC Ex 18) is the same as the conventional solar cells (SC ratio 18-1) to (SC).
It has been found that the characteristics are further superior to those of the ratio 18-7), and at a pressure of 50 mTorr or less, the raw material gas flow rate,
It was demonstrated that excellent characteristics can be obtained regardless of the manufacturing conditions such as the substrate temperature.

Example 19 Several solar cells were prepared by changing the position of the minimum value of the band gap (Eg) in the layer thickness direction, the size of the minimum value, and the pattern in Example 18, and the initial photoelectric conversion thereof was performed. The efficiency and durability characteristics were measured in the same manner as in Example 18. At this time, SiH of the i-type layer
₄ except changing pattern of gas flow rate and CH ₄ gas flow rate was the same as in Example 18. The solar cell having the band diagram shown in FIG. 12 was manufactured by changing the change patterns of the SiH ₄ gas flow rate and the CH ₄ gas flow rate.

Table 9 shows the results of examining the initial photoelectric conversion efficiency and durability characteristics of these solar cells produced. In the table,
Each value is standardized based on the value of (SC Ex 19-1). As can be seen from these results, the band gap of the i-type layer changes smoothly in the layer thickness direction regardless of the size of the minimum value of the band gap and the change pattern, and the position of the minimum value of the band gap is located in the i-type layer. It was found that the solar cell of the present invention, which is deviated in the p / i interface direction from the center position, is superior.

Example 20 A solar cell in which the layer A was formed by the mercury-sensitized CVD method was produced. Φ1 in the manufacturing equipment of FIG.
A quartz glass window of 00 mm and a thickness of 10 mm and a low-pressure mercury lamp were attached, and the light of the low-pressure mercury lamp was made incident on the deposition chamber through the quartz glass window. In addition, a shutter (referred to as a window shutter) that covers the quartz glass window is installed inside the deposition chamber so that deposits do not adhere to the quartz glass window. Further, mercury (purity 99.999%) was filled in a container (2048 in FIG. 4) having a valve at the inlet and the outlet. The container is a valve 2005 and a mass flow controller 201.
5 mounted between, by bubbling with B ₂ H ₆ / H ₂ gas, and to be able to introduce the vaporized mercury with B ₂ H ₆ / H ₂ gas into the deposition chamber.

When forming the layer A, the flow rate of the B ₂ H ₆ / H ₂ gas was set to 1000 sccm, flown into the deposition chamber, the pressure was set to 1.0 Torr, the shutter 415 was opened beforehand, and the low-pressure mercury lamp was turned on. The window shutter was opened for 60 seconds to form the A layer on the B layer. Other than this, the solar cell of FIG. 1 was produced under the same conditions, the same method, and the same procedure as in Example 18.

The manufactured solar cell (SC Ex 20) is (SC
Similar to the actual 18), conventional solar cells (SC ratio 18-1) ~
It was found that the initial photoelectric conversion efficiency and durability characteristics were better than those of (SC ratio 18-7).

Example 21 A solar cell was manufactured in which the stacking order of the n-type layer and the p-type layer was reversed. Table 10 shows layer forming conditions for the p-type layer, i-type layer, i-type Si layer, and n-type layer. i type Si
The layer deposition rate was 0.1 nm / sec. When forming the i-type layer, the SiH ₄ gas flow rate and the CH ₄ gas flow rate are changed as shown in the pattern of FIG. 6 so that the minimum value of the band gap comes from the p / i interface. In the same manner as in 18, a PH ₃ / H ₂ gas was used to form a laminated structure. The layers other than the semiconductor layer and the substrate were under the same conditions as in Example 18,
Made using the same method. The prepared solar cell (SC Ex 21) is the same as the conventional solar cell (SC Ex 18).
It was found that the initial photoelectric conversion efficiency and durability characteristics were better than those of the ratios 18-1) to (SC ratio 18-7).

Example 22 A non-single-crystal silicon carbide solar cell having a region having the maximum bandgap of the i-type layer on the p / i interface side and having a region thickness of 20 nm was produced.

It was manufactured using the same conditions and the same method as in Example 18, except that the flow rate change pattern of the i-type layer was changed to the pattern of FIG. 13-1. Next, the composition analysis of the solar cell was performed in the same manner as in Example 18, and the change in the band gap in the layer thickness direction of the i-type layer was examined based on FIG.
The result is 2. Fabricated solar cell (SC Ex 2
It was found that 2) has a better initial photoelectric conversion efficiency and durability characteristics than the conventional solar cells (SC ratio 18-1) to (SC ratio 18-7), like (SC Ex 18).

<Comparative Example 22> Some non-single-crystal silicon carbide solar cells were prepared in which there was a region having the maximum bandgap of the i-type layer on the p / i interface side, and the thickness of the region was variously changed. did. Except for the thickness of the region, the same conditions and methods as in Example 22 were used.

When the initial photoelectric conversion efficiency and the durability characteristics of the manufactured solar cell were measured, the region thickness was 1 nm or more,
At 30 nm or less, the solar cell of Example 18 (SC Ex 1
Even better initial photoelectric conversion efficiency and durability characteristics than 8) were obtained.

Example 23 A non-single-crystal silicon carbide solar cell having a region having the maximum bandgap of the i-type layer near the n / i interface and having a thickness of 15 nm was produced.

It was manufactured using the same conditions and the same method as in Example 18, except that the flow rate change pattern of the i-type layer was changed to the pattern of FIG. 13-3. Next, the composition analysis of the solar cell was performed in the same manner as in Example 18, and the change in the band gap of the i-type layer in the layer thickness direction was measured based on FIG.
The result is 4. Fabricated solar cell (SC Ex 2
It was found that 3) had better initial photoelectric conversion efficiency and durability characteristics than the conventional solar cells (SC ratio 18-1) to (SC ratio 18-7), like (SC Ex 18).

<Comparative Example 23> Several non-single-crystal silicon carbide solar cells were produced in which there was a region having the maximum bandgap of the i-type layer near the n / i interface, and the thickness of the region was variously changed. did. It was manufactured using the same conditions and the same method as in Example 23 except for the thickness of the region. When the initial photoelectric conversion efficiency and durability characteristics of the manufactured solar cell were measured, the initial photoelectric conversion efficiency and durability were better than those of the solar cell of Example 18 (SC Ex 18) when the region thickness was 1 nm or more and 30 nm or less. The characteristics were obtained.

Example 24 A solar cell using triethylboron (B (C ₂ H ₅ ) ₃ , hereinafter abbreviated as TEB) was prepared when forming a p-type layer.

Liquid TEB (purity 99.9 at room temperature and pressure)
Liquid cylinder with valve at inlet and outlet (Fig. 4)
2048). Attach the cylinder to the source gas supply unit, by bubbling with H ₂ gas, and to be able to introduce the TEB vaporized with H ₂ gas into the deposition chamber.

When forming the B layer, the TEB / H ₂ gas was introduced at 10 sccm instead of the B ₂ H ₆ / H ₂ gas into the deposition chamber under the same conditions and procedures as in Example 18 to form a layer on the i-type layer. The B layer was formed, H ₂ gas was introduced into the deposition chamber for 5 minutes, and then the deposition chamber was evacuated. Layer A is B ₂ H ₆ /
1000scc the TEB / H ₂ gas instead of H ₂ gas
m, the A layer was formed on the B layer under the same conditions and procedures as in Example 18 except that the gas was introduced into the deposition chamber, H ₂ gas was introduced into the deposition chamber for 5 minutes, and then the deposition chamber was evacuated.

Further, in the same manner, B layer, A layer, B
After forming the layer, the deposition chamber was evacuated.

Except for the p-type layer, the same conditions, methods and procedures as in Example 18 were used. Fabricated solar cell (SC Ex 2
It was found that 4) had better initial photoelectric conversion efficiency and durability characteristics than the conventional solar cells (SC ratio 18-1) to (SC ratio 18-7), like (SC Ex 18).

Example 25 A non-single-crystal silicon carbide solar cell having an i-type layer containing oxygen atoms was produced. i
In forming the mold layer, in addition to the gas flowing in Example 18, O ₂
The same conditions, the same method, and the same procedure as in Example 18 were used except that / He gas was introduced into the deposition chamber 401 at 10 sccm. The manufactured solar cell (SC Ex 25) is (SC Ex 1
Similar to 8), the conventional solar cells (SC ratio 18-1) to (S
It was found that the initial photoelectric conversion efficiency and durability characteristics were better than those of the C ratio 18-7).

Further, when the content of oxygen atoms in the i-type layer was measured by a secondary ion mass spectrometer (SIMS), it was found to be almost uniform and 2 × 10 ¹⁹ (pieces / cm ³ ). I understand.

Example 26 A non-single-crystal silicon carbide solar cell having a nitrogen atom in the i-type layer was produced.

When forming the i-type layer, NH ₃ / H ₂ gas was added at 5 sccm in the deposition chamber 401 in addition to the gas flowing in Example 18.
The same conditions and methods as in Example 18, except that
The same procedure was used. The prepared solar cell (SC Ex. 26) is similar to the conventional solar cell (SC Ex.
It was found that the initial photoelectric conversion efficiency and durability characteristics were better than those of 1) to (SC ratio 18-7). Moreover, when the content of nitrogen atoms in the i-type layer was measured by SIMS, it was found that the i-type layer was found to contain almost uniformly 3 × 10 ¹⁷ (pieces / cm ³ ).
It turned out that

Example 27 A non-single-crystal silicon carbide solar cell having an i-type layer containing oxygen atoms and nitrogen atoms was produced. When forming the i-type layer, the same conditions as in Example 18 were used, except that O ₂ / He gas was 5 sccm, NH ₃ / H ₂ gas was 5 sccm, and gas was introduced into the deposition chamber 401 in addition to the gas flowing in Example 18. , Same method, same procedure. The manufactured solar cell (SC Ex 27) is the same as (SC Ex 18)
Conventional solar cells (SC ratio 18-1) to (SC ratio 18-
It was found that the initial photoelectric conversion efficiency and durability characteristics were better than those of 7).

Further, when the contents of oxygen atoms and nitrogen atoms in the i-type layer were examined by SIMS, they were found to be almost uniformly contained.
It was found that they were 1 × 10 ¹⁹ (pieces / cm ³ ) and 3 × 10 ¹⁷ (pieces / cm ³ ), respectively.

Example 28 A non-single-crystal silicon carbide solar cell in which the hydrogen content of the i-type layer was changed according to the silicon content was produced. O ₂ / He gas cylinder with SiF ₄
When replacing the gas (purity 99.999%) cylinder and forming the i-type layer, according to the flow rate pattern of FIG.
The flow rates of H ₄ gas, CH ₄ gas, and SiF ₄ gas were changed. This solar cell (S
When the change of the band gap in the layer thickness direction of C ex. 28) was obtained, the same result as in FIG. 15-2 was obtained.

Further, the contents of hydrogen atoms and silicon atoms were analyzed in the layer thickness direction using SIMS. As a result, it was found that the content of hydrogen atoms has a distribution in the layer thickness direction corresponding to the content of silicon atoms, as in FIG. 15-3.

The initial photoelectric conversion efficiency and durability of this solar cell (SC Ex 28) were determined. As with the solar cell of Example 18, conventional solar cells (SC ratio 18-1) to (SC ratio)
It was found that the initial photoelectric conversion efficiency and durability characteristics were better than those of the ratio 18-7).

Example 29 When a semiconductor layer of the non-single crystal silicon carbide solar cell of FIG. 1 is formed by the manufacturing apparatus using the microwave plasma CVD method shown in FIG. 4, a silicon atom-containing gas (SiH ₄ gas) is used. ) And a carbon atom-containing gas (CH ₄ gas) were mixed at a distance of 5 m from the deposition chamber, and a non-single-crystal silicon carbide solar cell (SC Ex 29) was produced by the same method and the same procedure as in Example 18. It was found that the manufactured solar cell (SC Ex 29) had better initial photoelectric conversion efficiency and durability characteristics than (SC Ex 18).

Example 30 The tandem solar cell of FIG. 16 having a non-single-crystal silicon carbide semiconductor layer was produced using the manufacturing apparatus of FIG. 4 using the microwave plasma CVD method of the present invention.

First, a substrate was manufactured. As in Example 18, a 50 × 50 mm ² stainless steel substrate was ultrasonically cleaned with acetone and isopropanol and dried. 0.3μ on the surface of stainless steel substrate using the sputtering method
A reflective layer of Ag (silver) of m was formed. At this time, the substrate temperature was set to 350 ° C., and the substrate surface was made uneven (textured). A ZnO (zinc oxide) reflection-increasing layer of 1.0 μm was formed thereon at a substrate temperature of 350 ° C.

Next, the first n-type layer is formed on the substrate by the same procedure and the same method as in Example 18, and the first i-type layer, the first p-type layer and the second n-type layer are formed. The mold layer, the i-type Si layer, the second i-type layer, and the second p-type layer were sequentially formed. When forming the second i-type layer, S is formed according to the flow rate change pattern as shown in FIG.
The iH ₄ gas flow rate and the CH ₄ gas flow rate were changed, the i-type Si layer was formed at a deposition rate of 0.15 nm / sec, and the second p-type layer had the same laminated structure as in Example 18.

Next, as in Example 18, ITO (In ₂ O ₃₎ having a layer thickness of 80 nm was formed as a transparent electrode on the second p-type layer.
+ SnO ₂ ) and chromium (Cr) having a layer thickness of 10 μm as a collector electrode were deposited by a normal vacuum deposition method.

Thus, the production of the tandem solar cell using the microwave plasma CVD method is completed. This solar cell is called (SC Ex 30), and the manufacturing conditions of each semiconductor layer are shown in Table 11.

<Comparative Example 30-1> When forming the second i-type layer of FIG. 16, Si was formed in accordance with the flow rate change pattern of FIG.
A tandem solar cell was produced by the same method and procedure as in Example 30, except that the H ₄ gas flow rate and the CH ₄ gas flow rate were changed. This solar cell will be called (SC ratio 30-1).

<Comparative Example 30-2> In forming the second i-type layer shown in FIG. 16, the tandem was performed in the same manner as in Example 30 except that the μW power was changed to 0.5 W / cm ^3. Type solar cell was produced. This solar cell (SC ratio 30-2)
I will call it.

<Comparative Example 30-3> A tandem method and a procedure similar to those of Example 30 were applied, except that the RF power was set to 0.15 W / cm ³ when the second i-type layer shown in FIG. 16 was formed. Type solar cell was produced. This solar cell (SC ratio 30-
3).

[0333] <Comparative Example 30-4> when forming the second i-type layer in FIG. 16, except that the μW power 0.5 W / cm ^3, the RF power to 0.55 W / cm ³ Example 30 A tandem solar cell was produced by the same method and the same procedure. This solar cell will be called (SC ratio 30-4).

<Comparative Example 30-5> A tandem method and a procedure similar to those of Example 30 were applied except that the pressure in the deposition chamber 401 was set to 0.1 Torr when the second i-type layer shown in FIG. 16 was formed. Type solar cell was produced. This solar cell (SC ratio 3
0-5).

<Comparative Example 30-6> A tandem solar cell was manufactured by the same method and procedure as in Example 30, except that the deposition rate was 3 nm / sec when the i-type Si layer in FIG. 16 was formed. did. This solar cell is called (SC ratio 30-6).

Comparative Example 30-7 A tandem solar cell was manufactured by the same method and procedure as in Example 30, except that the i-type Si layer shown in FIG. 16 was formed with a layer thickness of 40 nm. This solar cell is called (SC ratio 30-7).

The initial photoelectric conversion efficiency and the durability characteristics of the produced tandem solar cells were measured in the same manner as in Example 18. (SC Ex 30) shows that the conventional tandem solar cell (SC ratio 30-1 ) To (SC ratio 30-7), the initial photoelectric conversion efficiency and durability characteristics were found to be better.

Example 31 Using the manufacturing apparatus of FIG. 4 using the microwave plasma CVD method of the present invention, the triple solar cell of FIG. 17 having a non-single crystal silicon carbide semiconductor layer was manufactured.

First, a substrate was manufactured. As in Example 18, a 50 × 50 mm ² stainless steel substrate was ultrasonically cleaned with acetone and isopropanol and dried. Using the same sputtering method as in Example 30, 0.3 μm Ag (silver) was formed on the surface of the stainless steel substrate at a substrate temperature of 350 ° C.
Reflective layer is formed, and the substrate surface is uneven (textured)
I chose On top of that, 1.0 μm of Zn
A reflection enhancing layer of O (zinc oxide) was formed.

Next, in place of the NH ₃ / H ₂ gas cylinder, G
An eH ₄ gas (purity 99.999%) cylinder was connected, and the preparation for film formation was completed by the same method and procedure as in Example 18. The first n-type layer was formed on the substrate by the same procedure and the same method as in Example 18, and the first i-type layer, the first p-type layer, the second n-type layer, and the second n-type layer were formed. i-type layer, second p-type layer, third
The n-type layer, the i-type Si layer, the third i-type layer, and the third p-type layer were sequentially formed.

When forming the third i-type layer, the SiH ₄ gas flow rate and the CH ₄ gas flow rate are changed in accordance with the flow rate change pattern as shown in FIG. 5 to form 0.15 n when forming the i-type Si layer.
formed with a deposition rate of m / sec, and further with a second p-type layer,
The third p-type layer had a laminated structure as in Example 18.

Then, as in Example 18, ITO (In ₂₎ having a layer thickness of 80 nm was formed as a transparent electrode on the third p-type layer.
O ₃ + SnO ₂ ) and chromium (Cr) having a layer thickness of 10 μm as a collecting electrode were deposited by a normal vacuum deposition method.

As described above, the production of the triple type solar cell using the microwave plasma CVD method is completed. This solar cell is referred to as (SC Ex 31), and the manufacturing conditions of each semiconductor layer are shown in Table 12.

<Comparative Example 31-1> When the third i-type layer of FIG. 17 is formed, Si is formed according to the flow rate change pattern of FIG.
A triple type solar cell was produced by the same method and procedure as in Example 31, except that the H ₄ gas flow rate and the CH ₄ gas flow rate were changed. This solar cell will be called (SC ratio 31-1).

<Comparative Example 31-2> When the third i-type layer shown in FIG. 17 was formed, a triplet was formed in the same manner as in Example 31 except that the μW power was changed to 0.5 W / cm ^3. Type solar cell was produced. This solar cell (SC ratio 31-2)
I will call it.

<Comparative Example 31-3> When the third i-type layer shown in FIG. 17 was formed, a triplet was formed in the same manner as in Example 31 except that the RF power was set to 0.15 W / cm ^3. Type solar cell was produced. This solar cell (SC ratio 31-
3).

[0347] <Comparative Example 31-4> 3 at the time of forming the i-type layer, except for the μW power 0.5 W / cm ^3, the RF power to 0.55 W / cm ³ Example 31 17 A triple type solar cell was manufactured by the same method and the same procedure. This solar cell will be called (SC ratio 31-4).

<Comparative Example 31-5> When the third i-type layer shown in FIG. 17 is formed, the pressure in the deposition chamber 401 is set to 0.08 Torr.
A triple type solar cell was manufactured by the same method and the same procedure as in Example 31, except that This solar cell is called (SC ratio 31-5).

<Comparative Example 31-6> A tandem solar cell was manufactured by the same method and procedure as in Example 31, except that the deposition rate was 3 nm / sec when the i-type Si layer in FIG. 17 was formed. did. This solar cell will be called (SC ratio 31-6).

Comparative Example 31-7> When forming the i-type Si layer of FIG. 17, a triple type solar cell was manufactured by the same method and procedure as in Example 31, except that the layer thickness was 40 nm. This solar cell will be called (SC ratio 31-7>).

The initial photoelectric conversion efficiency and durability of these produced triple solar cells were measured by the same method as in Example 18. (SC Ex 31) shows that the conventional triple solar cells (SC ratio 31-1 ) To (SC ratio 31-7), the initial photoelectric conversion efficiency and durability characteristics were better.

Example 32 Using the manufacturing apparatus of FIG. 4 using the microwave plasma CVD method of the present invention, FIG.
We produced a triple-type solar cell of, made it into a module, and applied it to a power generation system.

A triple solar cell of 50 × 50 mm ² (SC Ex 3
65 pieces of 1) were produced. An adhesive sheet made of EVA (ethylene vinyl acetate) is placed on a 5.0 mm thick aluminum plate, a nylon sheet is placed on the sheet, and the solar cells fabricated on the sheet are arranged in series and parallel. Was made. Put the EVA adhesive sheet on it,
Further, a fluororesin sheet was placed thereon, and vacuum laminated to form a module. The initial photoelectric conversion efficiency of the manufactured module was measured by the same method as in Example 18.

The manufactured module was connected to the circuit showing the power generation system in FIG. An external light that lights at night was used as the load. The whole system was operated by the storage battery and the power of the module, and the module was installed at the angle that could collect the most sunlight. Measure the photoelectric conversion efficiency after one year,
Photodegradation rate (photoelectric conversion efficiency after 1 year / initial photoelectric conversion efficiency)
I asked. This module will be called (MJ real 32).

<Comparative Example 32-1> A conventional triple solar cell (SC ratio 31-X) (X: 1 to 7) was used as a comparative example 31-.
Sixty-five pieces were prepared under the same conditions, the same method, and the same procedure as X, and were modularized in the same manner as in Example 32. This module will be called (MJ ratio 32-X).

The initial photoelectric conversion efficiency and the photoelectric conversion efficiency after one year were measured under the same conditions, the same method, and the same procedure as in Example 32, and the photodegradation rate was obtained.

As a result, the photodegradation rate of (MJ ratio 32-X) was as follows with respect to (MJ actual 32).

[0358] From the above results, it was found that the solar cell module of the present invention has more excellent photodegradation characteristics than the conventional solar cell module.

Example 33 When a solar cell was manufactured by the same method as in Example 31, the RF plasma CVD method was used at the p / i interface to form the triple of FIG. 19 having the second i-type Si layer. Type solar cell was produced. A first n-type layer was formed on the substrate in the same manner as in Example 31, and further, a first i-type layer, a first p-type layer, a second n-type layer, a second i-type layer, Second
P-type layer, third n-type layer, first i-type Si layer, third i-type layer
The mold layer, the second i-type Si layer, and the third p-type layer were sequentially formed. When forming the third i-type layer, the SiH ₄ gas flow rate and the CH ₄ gas flow rate were changed according to the flow rate change pattern as shown in FIG. 13-1. When forming the first i-type Si layer and the second i-type Si layer, the deposition rate is 0.15 nm / sec.
So that

Then, in the same manner as in Example 18, ITO (In ₂ O ₃ +) having a layer thickness of 80 nm was formed as a transparent electrode on the third p-type layer.
SnO ₂ ) and chromium (Cr) having a layer thickness of 10 μm as a collector electrode were deposited by a normal vacuum deposition method. As described above, the production of the triple solar cell using the microwave plasma CVD method is completed. This solar cell is called (SC Ex 33), and the manufacturing conditions of each semiconductor layer are shown in Table 13.

The initial photoelectric conversion efficiency and durability characteristics of the produced triple solar cell of FIG. 19 were measured by the same method as in Example 1. As a result, (SC Ex 33) shows that the conventional triple solar cell (SC ratio 31- It was found that the initial photoelectric conversion efficiency and durability characteristics were better than those of 1) to (SC ratio 31-7).

Example 34 When the solar cell of FIG. 19 is manufactured in the same manner as in Example 33, it is more preferable than the i-type Si layer (first i-type Si layer) formed at the n / i interface. , P / i
A triple solar cell in which the i-type Si layer (second i-type Si layer) formed at the interface was thicker was manufactured.

A first n-type layer was formed on the substrate by the same method, procedure and conditions as in Example 33 except that the thickness of the second i-type Si layer was 20 nm. Layer, first p
Type layer, second n-type layer, second i-type layer, second p-type layer, third n-type layer, first i-type Si layer, third i-type layer, second i-type layer A type Si layer and a third p-type layer were sequentially formed.

Next, as in Example 18, ITO (In ₂ O ₃ +) having a layer thickness of 80 nm was formed as a transparent electrode on the third p-type layer.
SnO ₂ ) and chromium (Cr) having a layer thickness of 10 μm as a collector electrode were deposited by a normal vacuum deposition method. As described above, the production of the triple solar cell using the microwave plasma CVD method is completed. This solar cell will be called (SC Ex 34).

The initial photoelectric conversion efficiency and durability characteristics of the produced triple type solar cell of FIG. 19 were measured by the same method as in Example 33. As a result, (SC Ex. 34) was obtained from the triple type solar cell of (SC Ex. 33). It has been found that also has a better initial photoelectric conversion efficiency and durability characteristics.

As described above, it was proved that the effect of the photovoltaic element of the present invention was exhibited regardless of the element structure, element material, and element manufacturing conditions.

[0367]

As described above, the photovoltaic device of the present invention prevents recombination of photoexcited carriers, improves the open circuit voltage and the carrier range of holes, and improves the photoelectric conversion efficiency.

Further, the photovoltaic element of the present invention has improved conversion efficiency when the irradiation light is weak. Further, the photovoltaic element of the present invention is less likely to lower the photoelectric conversion efficiency when annealed under vibration for a long period of time.

Further, according to the method for manufacturing a photovoltaic element of the present invention, a photovoltaic element having the above effect can be formed with a high yield.

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

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

[Table 6]

[Table 7]

[Table 8]

[Table 9]

[Table 10]

[Table 11]

[Table 12]

[Table 13]

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a layer structure of a photovoltaic element of the present invention.

FIG. 2 is a band diagram of a photoconductive layer in the photovoltaic device of the present invention.

FIG. 3 is a band diagram of a photoconductive layer in the photovoltaic device of the present invention.

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

FIG. 5 is a graph showing SiH ₄ and CH ₄ gas flow rate patterns when forming an i-type layer.

FIG. 6 is a graph showing a SiH ₄ and CH ₄ gas flow rate pattern when forming an i-type layer.

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

FIG. 8 is a conceptual diagram showing changes in the band gap in the layer thickness direction.

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

FIG. 10 is a graph showing the dependence of the 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 conceptual diagram showing a change in band gap in the layer thickness direction.

FIG. 13 is a diagram showing changes in the flow pattern and band gap in the layer thickness direction.

FIG. 14 is a graph showing a temporal change pattern of μW power.

FIG. 15 is a flow chart (1) when hydrogen atoms are distributed,
The graph which shows (2) band gap and (3) content.

FIG. 16 is a schematic cross-sectional view showing the layer structure of a tandem solar cell.

FIG. 17 is a schematic cross-sectional view showing the layer structure of a triple solar cell.

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

FIG. 19 is a schematic cross-sectional view showing another configuration example of a triple solar cell.

FIG. 20 is a schematic diagram showing a cross-sectional TEM image of a p-type layer.

[Explanation of symbols]

101 conductive substrate 102 n-type layer 103 i-type layer (i-type Si layer) deposited by RF plasma CVD method 104 i-type layer deposited by microwave plasma method 105 p-type layer 106 transparent electrode 107 current collecting electrode 211 , 221, 311, 321, 331, 341, 3
51,361,371 i-type layer by microwave plasma CVD method 312,322,332,33,342,343,35
2,353,362,372,373 i-type layer by microwave plasma CVD method with a constant band gap 212,222,313,323,334,344,3
54, 364, 374 i-type layer (i-type Si layer) by RF plasma CVD method 400 deposition apparatus 401 deposition chamber 402 vacuum gauge 403 RF power supply 404 substrate 405 heating heater 407 conductance valve 408 auxiliary valve 409 leak valve 410 RF electrode 411 gas introduction Tube 411 412 Waveguide 413 Dielectric window 2000 Raw material gas supply device 2001-2007, 2021-2027 Valve 2011-2017 Mass flow controller 2031-2037 Pressure regulator 2041-2047, 2048 Raw material gas cylinder

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Naoto Okada 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yuzo Koda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Co., Ltd. (72) Inventor Fukateru Matsuyama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (11)

[Claims] 1. A photovoltaic element comprising at least a p-type layer made of a silicon-based non-single-crystal semiconductor material, a photoconductive layer (a layer made of a plurality of i-type layers), and an n-type layer. The photoconductive layer includes an i-type layer deposited on the p-type layer side by a microwave plasma CVD method and the n-type layer.
A laminated structure including at least an i-type layer deposited on the die layer side by an RF plasma CVD method, wherein the i-type layer deposited by the microwave plasma CVD method contains at least silicon atoms and carbon atoms. However, the position of the minimum value of the band gap is an i-type layer formed deviating from the center of the i-type layer in the p-type layer direction, and the i-type layer deposited by the RF plasma CVD method is at least silicon. A photovoltaic element comprising atoms and having a layer thickness of 30 nm or less. 2. The i-type layer deposited by the microwave plasma CVD method has a maximum bandgap value in at least one of a p-type layer direction and an n-type layer direction from the center of the i-type layer, The region of the maximum value of the band gap is 1 or more and 30 nm or less.
Photovoltaic device according to. 3. An i-type layer formed by the microwave plasma CVD method and / or an i-type layer formed by the RF plasma CVD method
The photovoltaic element according to claim 1 or 2, wherein the mold layer contains oxygen atoms and / or nitrogen atoms. 4. The hydrogen content contained in the i-type layer formed by the microwave plasma CVD method changes according to the content of silicon atoms.
The photovoltaic element according to any one of 1. 5. The i-type layer deposited by the RF plasma CVD method is simultaneously doped with an element of Group III and an element of Group V of the periodic table.
4. The photovoltaic element according to any one of 4 above. 6. The p-type layer and the microwave plasma C
The photovoltaic element according to claim 1, wherein an i-type layer formed by an RF plasma CVD method is provided between the photovoltaic element and the i-type layer formed by the VD method. 7. A layer in which at least one of the p-type layer and the n-type layer contains a Group III element and / or a Group V element of the periodic table as main constituent elements, and a silicon atom containing a valence electron control agent. The photovoltaic element according to any one of claims 1 to 6, which has a laminated structure with a layer serving as a main constituent element. 8. A group III element of the periodic table or / and a group V element.
The photovoltaic element according to claim 7, wherein the layer having a group element as a main constituent element has a layer thickness of 1 nm or less. 9. A method of manufacturing a photovoltaic element, which is configured by laminating at least a p-type layer made of a silicon-based non-single-crystal semiconductor material, a photoconductive layer (a layer made of a plurality of i-type layers), and an n-type layer. In the above, the i-type layer on the p-type layer side of the photoconductive layer is decomposed by 100% into a raw material gas containing at least a silicon atom-containing gas and a carbon atom-containing gas at a pressure of 50 mTorr or less. The microwave plasma CVD method in which the microwave energy lower than the microwave energy required for the above and the RF energy higher than the microwave energy are simultaneously actuated, and the position of the minimum value of the band gap is higher than the position of the center of the i-type layer by p. The i-type layer on the n-type layer side is formed and deposited so as to be offset in the direction of the die layer by using a source gas containing at least a silicon atom-containing gas as R
A method of manufacturing a photovoltaic element, characterized in that it is formed by an F plasma CVD method at a deposition rate of 2 nm / sec or less and 30 nm or less. 10. The method of manufacturing a photovoltaic element according to claim 9, wherein the silicon atom-containing gas and the carbon atom-containing gas are mixed at a distance of 5 m or less from the deposition chamber in the microwave plasma CVD method. . 11. A photovoltaic element according to any one of claims 1 to 8, and a storage battery for accumulating the electric power supplied from the photovoltaic element and / or supplying the electric power to an external load. And a control system for monitoring the voltage and / or current of the photovoltaic element and controlling the power supplied from the photovoltaic element to the storage battery and / or the external load. Power generation system.