JP2812377B2 - Photovoltaic element, method of manufacturing the same, and power generation system using the same - Google Patents

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 device 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 device in which a band gap in an i-type layer is changed, and further relates to a method for depositing the photovoltaic device by a microwave plasma CVD method. In addition, the present invention 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, light whose i-layer contains silicon atoms and germanium atoms and whose band gap changes in the i-type layer. Various proposals have been made for electromotive force elements as described below. For example,
(1) "Optimum deposition co
indications for a- (Si, Ge): H
using a triode-configurat
ed rf glow discharge system
em ", JA Bragagnolo, P. Litt
lefield, A .; Mastrovito and
G. FIG. Storti, Conf. Rec. 19th IE
EE Photovoltaic specialist
s Conference-1987, pp. 147-64. 878,
(2) "Efficiency improbemen"
tin amorphous-SiGe: H sol
ar cells and it's applicat
ion to tandem type solar
cells, "S. Yoshida, S. Yamana
ka, M .; Konagai and K.K. Takaha
shi, Conf. Rec. 19th IEEE Ph
otovoltaic Specialists Con
reference-1987, pp. 139-143. 1101, (3) "
Stability and terrestrial
application of a-Si tand
em type solar cells ", A. Hi
roe, H .; Yamagishi, H .; Nisio,
M. Kondo, and Y. Tawada, Con
f. Rec. 19th IEEEPHOTOVOLTA
ic Specilists Conference,
1987, pp. 1111, (4) "Preparat
ion of high quality a-SiG
e: H films and it's applica
Tion to the high efficiency
cy triple-junction amorph
ous solar cells, "K. Sato,
K. Kawabata, S .; Terazono, H .; S
Asaki, M .; Deguchi, T .; Itagak
i, H .; Morikawa, M .; Aiga and
K. Fujikawa, Conf. Rec. 20th
IEEE PhotovoltaicSpecilis
ts Conference, 1988 pp. 73,
(5) USP 4,816,082, (6) USP 4,4
71,155, (7) USP 4,782,376 and the like.

A theoretical study of the characteristics of a photovoltaic device in which the band gap is changed is described, for example, in (8) “A.
novel design for amorphou
s Silicon alloy solar cell
ls ", S. Guha, J. Yang, A. Pawli
kiewicz, T .; Glatfilter, R.A. Ro
ss, and S.S. R. 0vshinsky, Con
f. Rec. 20th IEEE Photovoltt
aic Specialists Conference
-1988 pp. 79, (9) "Numerical
mode1ing of multijunction
n, amorphous silicon based
PIN solar cells ", A. H.P.
awlikiewicz and S.A. Guha, Co
nf. Rec. 20th IEEE Photovol
taic Specialists Conference
e-1988 pp. 251 have been reported.

In such a conventional photovoltaic element, p
A layer having a variable band gap is inserted at the interface for the purpose of preventing recombination of photoexcited carriers near the / i, n / i interface, increasing the open-circuit voltage, and improving the hole carrier range. doing.

[0005]

A conventional photovoltaic device containing silicon atoms and germanium atoms and having a changed band gap requires higher performance and reliability in practical use, and recombination of photoexcited carriers. It is desired to further improve the suppression of the voltage drop, the open circuit voltage and the hole carrier range.

In addition, the conventional photovoltaic element has a problem that the conversion efficiency is reduced when the light applied to the photovoltaic element is weak.

Further, the conventional photovoltaic element has a problem that the i-layer has a strain, and if it is annealed where there is vibration or the like, the photoelectric conversion efficiency is reduced.

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

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

It is a further object of the present invention to provide a photovoltaic element in which the photoelectric conversion efficiency is unlikely to decrease when annealing is performed under vibration for a long period of time.

Still another object of the present invention is to provide a photovoltaic element whose photoelectric conversion efficiency is unlikely to change with changes in temperature.

Another object of the present invention is to provide a method of manufacturing a photovoltaic device which has attained the above object.

Still another object of the present invention is to provide a system using a photovoltaic element which has achieved the above object.

[0014]

SUMMARY OF THE INVENTION The present invention solves the conventional problems, and as a result of intensive studies to achieve the object of the present invention, the photovoltaic element of the present invention is a silicon-based non-single-crystal semiconductor material. In a photovoltaic device comprising at least a p-type layer, an i-type layer and an n-type layer, the i-type layer contains at least silicon atoms and carbon atoms,
Bandgap changes in the layer thickness direction of the mold layer, and valence <br/> electronic control agent as a valence electron control agent and an acceptor which serves as a donor to the i-type layer is doped, the p-type and the i-type layer The content of the valence control agent in the vicinity of the layer and / or the interface with the n-type layer is larger than that in the i-type layer.

In a preferred embodiment of the photovoltaic device of the present invention, the interface between the i-type layer and the p-type layer or the n-type layer is used.
A photovoltaic element having a region having a maximum band gap at at least one of the interfaces between the mold layer and the i-type layer, wherein the layer having the maximum band gap has a layer thickness of 1 nm or more and 30 nm or less. is there.

Further, a desirable mode of the photovoltaic device of the present invention is a photovoltaic device in which a valence electron controlling agent serving as a donor and a valence electron controlling agent serving as an acceptor are simultaneously doped in an i-type layer. The valence electron controlling agent is preferably a Group III element of the periodic table, and the valence electron controlling agent serving as an acceptor is preferably a Group V element of the periodic table. Further, the valence electron controlling agent is more preferably distributed in the i-type layer.

In addition, a desirable mode of the photovoltaic device of the present invention is a photovoltaic device in which oxygen atoms and / or nitrogen atoms are contained in the i-type layer.

The oxygen atom and / or the nitrogen atom
Content has increased or decreased with respect to the carbon atom content
Is preferred. Further, it is characterized in that the hydrogen content contained in the i-type layer changes corresponding to the silicon atom content.

Further, in a desirable mode of the photovoltaic device 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 a main constituent element. A photovoltaic element having a stacked structure of a layer having a valence electron controlling agent and a layer containing silicon atoms as a main constituent element. It is preferable that the thickness of the layer mainly containing a Group III element and / or a Group V element of the periodic table be 1 nm or less.

The method of manufacturing a photovoltaic device according to the present invention is characterized in that at least a p-type layer, an i-type layer and an n-type layer made of a silicon-based non-single-crystal semiconductor material are laminated, and the i-type layer Atoms and carbon atoms, and the band gap is
In the method for manufacturing a photovoltaic device in which the minimum value of the band gap changes smoothly in the layer thickness direction of the mold layer and is offset toward the interface direction between the p-type layer and the i-type layer, the i-type layer is at least silicon atom-containing gas and carbon-containing gas, using a material gas containing a gas containing valence electron control agent serving as a donor, and a gas containing valence electron control agent serving as the acceptor, was formed by a plasma CVD method, Further, the supply amounts of the gas containing the valence electron controlling agent serving as the donor and the gas containing the valence electron controlling agent serving as the acceptor are determined by changing the supply amount between the i-type layer and the p-type layer and / or the n-type layer. Is characterized in that it is larger than other parts in the vicinity of.
In a desirable mode of the photovoltaic device of the present invention, the i-type layer is formed by a microwave plasma CVD method, and the magnitude of the applied microwave energy is larger than the microwave energy for decomposing the source gas by 100%. Is also low
And applying RF energy, wherein the magnitude of the RF energy is higher than the microwave energy.

In a preferred embodiment of the method of manufacturing a photovoltaic device according to the present invention, the gas containing the valence electron controlling agent is supplied in a large amount in a narrow band gap and a small amount in a wide band gap. Further, it is preferable that the source gas contains an oxygen atom and / or a nitrogen atom. Further, it is preferable that the silicon-containing gas and the carbon atom-containing gas are mixed at a distance of 5 m or less from the deposition chamber.

A power generation system using the photovoltaic element of the present invention includes a photovoltaic element of the present invention, a storage battery for storing power supplied from the photovoltaic element and supplying power to an external load. A control system that monitors voltage and / or current of the photovoltaic element and controls power supplied from the photovoltaic element to the storage battery and / or the external load.

[0023]

The operation and the configuration 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. The photovoltaic element of the present invention contains a conductive substrate 101 having a light reflection layer and a light reflection enhancement layer, an n-type (or p-type) silicon-based non-single-crystal semiconductor layer 102, and at least silicon atoms and carbon atoms. The semiconductor device includes a substantially i-type non-single-crystal semiconductor layer 103, a p-type (or n-type) silicon-based non-single-crystal semiconductor layer 104, a transparent electrode 105, a current collecting electrode 106, and the like.

In the i-type layer, the minimum value of the band gap is biased toward the interface between the p-type layer and the i-type layer, and the electric field in the conduction band is large on the p-type layer side of the i-type layer. And holes are efficiently separated, and recombination of electrons and holes near the interface between the p-type layer and the i-type layer can be reduced. In addition, since the electric field in the valence band increases from the i-type layer toward the n-type layer, recombination between electrons and holes photo-excited in the vicinity of the i-type layer and the n-type layer can be reduced.

Further, by simultaneously adding a valence electron controlling agent serving as a donor and a valence electron controlling agent serving as an acceptor to the i-type layer, the carrier range of electrons and holes can be extended. In particular, by including a relatively large amount of the valence electron controlling agent at the maximum carbon content, the carrier range of electrons and holes can be effectively lengthened. As a result, the high electric field near the interface between the p-type layer and the i-type layer and the high electric field near the interface between the n-type layer and the i-type layer can be more effectively utilized, and the electrons excited in the i-type layer can be reduced. Hole collection efficiency can be significantly improved.

In the vicinity of the interface between the p-type layer and the i-type layer and in the vicinity of the interface between the n-type layer and the i-type layer, defect levels (so-called D
⁻ , D ⁺ ) is compensated by the valence electron controlling agent, so that dark current (during reverse bias) due to hopping conduction via defect levels is reduced. In particular, in the vicinity of the interface, the valence electron controlling agent is contained more than the inside of the i-type layer,
It is possible to reduce internal stress such as strain due to a sudden change of a constituent element peculiar to the interface, and as a result, it is possible to reduce defect levels near the interface. As a result, the open voltage and the fill factor of the photovoltaic element can be improved.

In addition, by simultaneously containing a valence electron controlling agent serving as a donor and a valence electron controlling agent serving as an acceptor in the i-type layer, the durability against light degradation is increased.
Although the details of the mechanism are unknown, it is generally considered that the dangling bonds generated by light irradiation become recombination centers of carriers and deteriorate the characteristics of the photovoltaic element. In the case of the present invention, both the valence electron controlling agent serving as a donor and the valence electron controlling agent serving as an acceptor are contained in the i-type layer formed by the microwave plasma CVD method.
00% not activated. As a result, even if dangling bonds are generated by light irradiation, it is considered that they react with the inactive valence electron controlling agent to compensate for dangling bonds.

Further, even when the light intensity applied to the photovoltaic element is low, the probability that the photoexcited electrons and holes are trapped is reduced because the defect level is compensated by the valence electron controlling agent. As described above, since the dark current at the time of reverse bias is small, a sufficient electromotive force is generated. Therefore, even when the intensity of light irradiated on the photovoltaic element is low, the photoelectric conversion element exhibits excellent photoelectric conversion efficiency.

In addition, the photovoltaic device of the present invention is one in which the photoelectric conversion efficiency does not easily decrease even when annealing is performed under vibration for a long period of time. Although the detailed mechanism is unknown, the decrease in the photoelectric conversion efficiency of the conventional photovoltaic element is considered as follows. That is, in order to continuously change the band gap, the constituent elements are also changed to form a photovoltaic element. Therefore, strain is accumulated inside the photovoltaic element, and many weak couplings exist inside the photovoltaic element. Then, it is considered that as a result of the vibration, a weak bond in the i-type non-single-crystal semiconductor is broken and a dangling bond is formed, so that the photoelectric conversion efficiency is reduced. On the other hand, in the case of the present invention, the local flexibility is increased by the simultaneous addition of the valence electron controlling agent serving as the donor and the valence electron controlling agent serving as the acceptor, and the photovoltaic element can be used even in annealing by long-term vibration. It is considered that the decrease in the photoelectric conversion efficiency of can be suppressed. In addition, it is conceivable that an unactivated donor or acceptor is mainly coordinated with three, thereby increasing local flexibility. As a result, it is considered that the photoelectric conversion efficiency does not easily decrease even if the annealing is performed under the vibration for a long time. However, unactivated donors and acceptors must be below a certain amount to form defects. Therefore, the preferable amount of the unactivated donor or acceptor is 0.1 to 1000 ppm.

In the present invention, for example, the p-type layer
Layers containing Group III elements as main constituent elements (hereinafter referred to as Periodic Table III
A layer containing a Group V 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 controlling agent and containing silicon atoms as a main constituent element (hereinafter referred to as a doping layer B). With the stacked 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, the side of the p-type layer in contact with the photoconductive layer is preferably a layer containing a valence electron controlling agent and containing silicon as a main constituent element (doping layer B).
By connecting the photoconductive layer and the p-type layer in this manner, it is possible to reduce defects between the photoconductive layer and the p-type layer.

The optimum layer thickness of the layer (doping layer A) comprising Group III atoms of the periodic table as a main constituent element of the p-type layer is 0.01 to 1 nm. It is preferable that the hydrogen content in the layer containing the Group III element of the periodic table as a main constituent element is 5% or less.
The content of the valence electron controlling agent contained in the layer containing the valence electron controlling agent constituting the p-type layer and containing silicon atoms as the main constituent element (doping layer B) is 1500 ppm to 10000 p.
pm is a preferred range.

Although the p-type layer has been described above, the same effect can be obtained by forming the n-type layer with a similar laminated structure.

Next, the present invention will be described with reference to a band diagram of a photoconductive layer.

FIG. 2-1 is a schematic explanatory view of an example in which the band gap of the photovoltaic device of the present invention changes. This figure shows the change of the band gap in the i-type layer based on 1/2 (Eg / 2) of the band gap. In the figure, the left side is the side of the n-type layer (not shown), and the right side is the side of the p-type layer (not shown). The example of FIG. 2-1 is configured such that the minimum value of the band gap is near the p-type layer, and the maximum value of the band gap is in contact with the p-type layer side and the n-type layer. .

FIG. 2-2 is a schematic explanatory diagram of a change in band gap similar to FIG. 2-1. In FIG. 2B, as in FIG. 2A, the minimum value of the band gap is closer to the p-type layer (not shown), but the maximum value of the band gap is closer to the p-type layer. It is constituted in. With the band gap configuration shown in FIG. 2-3, the open-circuit voltage can be particularly increased.

FIGS. 3-1 to 3-7 show examples of a photovoltaic device having a band gap constant region in the i-type layer near the p / i interface or / and near the n / i interface. Each figure illustrates a change in band gap based on Eg / 2. An n-type layer (not shown) is on the left side of the band diagram, and a p-type layer (not shown) is on the right side of the band diagram.

FIG. 3A shows a region 312 having a constant band gap in the i-type layer on the p-type layer side and having a band gap of n.
This is an example of a region 311 decreasing from the mold layer side toward the p-type layer. Then, the minimum value of the band gap is in the region 31
2 and the region 311. The area 31
The band junction between 1 and region 312 is one that is discontinuously connected. By providing such a region having a constant band gap, dark current due to hopping conduction via a defect level at the time of reverse bias of the photovoltaic element can be suppressed as much as possible. The voltage increases.

The layer thickness of the region 312 having a constant band gap is a very important factor, and the preferable range of the layer thickness is 1 to 30 nm. If the layer thickness in the region where the band gap is constant is smaller than 1 nm, it is impossible to suppress dark current due to hopping conduction via defect levels, and it is impossible to expect an improvement in the open-circuit voltage of the photovoltaic element. On the other hand, when the thickness is larger than 30 nm, the region 312 having a constant band gap and the region 311 having a changed band gap are provided.
Since the photoexcited holes are more likely to be accumulated near the interface, the collection efficiency of the photoexcited carriers decreases. That is, the short-circuit photocurrent is reduced.

FIG. 3B shows that an i-type layer 322 having a constant gap is provided in the i-type layer at the p / i interface, and the band gap is near the n / i interface in the region 321 where the band gap changes. This is an example in which the area is equal to the area 322.

FIG. 3C shows regions 332, 33 having a fixed band gap on the i-type layer side of the p / i interface and the n / i interface.
3 is provided. By providing a region having a constant band gap on the i-type layer side of the p / i interface and the n / i interface, when a reverse bias is applied to the photovoltaic element, the dark current is further reduced, and The open voltage of the power element can be increased.

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

FIG. 3-4 shows the p / i interface or / and n /
a region 342 having a constant band gap on the i-type layer side of the i interface,
There is a region 341 having a band gap 343, and the position where the band gap is minimum is offset toward the p-type layer side in the region 341, and the band gap of the region 341 and the regions 342, 343 Is an example in which the band gaps are continuous. By making the band gap continuous, electrons and holes photo-excited in the region where the band gap of the i-type layer is changed can be efficiently converted into the n-type layer and the p-type layer.
Each can be collected in a mold layer. In particular, when the constant band gap regions 342 and 343 are as thin as 5 nm or less, the region where the band gap of the i-type layer changes rapidly reduces the dark current when a reverse bias is applied to the photovoltaic element. Therefore, the open-circuit voltage of the photovoltaic element can be increased.

FIG. 3-5 shows that the region 351 where the band gap is changed is the region 353 or 3 where the band gap is constant.
This is an example in which the connection is discontinuously and relatively loosely connected to the connection 52. However, since the connection is made gently in the direction in which the band gap expands in the region where the band gap is constant and in the region where the band gap is changing, carriers that are photoexcited in the region where the band gap is changing can be efficiently fixed in the band gap. Is implanted into the region. As a result, the collection efficiency of the photoexcited carriers increases.

Whether a region having a constant band gap and a region having a changing band gap are connected continuously or discontinuously is determined by determining whether the region having a constant band gap or the region having a rapidly changing band gap. It depends on the layer thickness. When the region having a constant band gap is as thin as 5 nm or less and the layer thickness of the region where the band gap changes rapidly is 10 nm or less, the region having a constant band gap and the region where the band gap changes are continuously formed. The connection increases the photoelectric conversion efficiency of the photovoltaic element. On the other hand, when the layer thickness of the region where the band gap is constant is more than 5 nm and the layer thickness of the region where the band gap changes rapidly is 10 to 30 nm, the band gap changes with the region where the band gap is constant. The conversion efficiency of the photovoltaic element is improved when the area is discontinuously connected.

FIG. 3-6 shows an example in which a region where the band gap is constant and a region where the band gap changes are connected in two stages. In this example, the position where the band gap is minimal is closer to the p-type layer. Efficiency of photoexcited carriers in the region where the bandgap is changing can be improved by connecting the bandgap to a fixed region with a wide bandgap through a stage where the bandgap is gradually widened from a position where the bandgap is extremely small and a stage where the bandgap is rapidly expanded. It can be collected well. Also, in FIG. 3-6, the i-type layer near the n-type layer has a region where the band gap changes rapidly toward the n-type layer.

FIG. 3-7 shows a region having a constant band gap in both the p-type layer and the n-type layer and the constant band gap region in the p-type layer. This is an example in which the connection is made through a two-step bandgap change from the first to the second, and the bandgap is fixedly connected to a region where the bandgap is constant on the n-type layer side.

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

Further, when the valence electron controlling agent is contained in the i-type layer, the carrier range in the i-type layer can be increased, and the carrier collection efficiency can be increased.
Particularly, the valence electron controlling agent is used in a place where the carbon content is high,
By reducing the number at a non-existent location, the collection efficiency of the photoexcited carriers can be further increased.

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

In the photovoltaic device having a continuously changing band gap according to the present invention, the inclination of the tail state of the valence band is an important factor affecting the characteristics of the photovoltaic device. 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 value of the band gap continue smoothly.

Although the photovoltaic element having the pin structure has been described above, it is needless to say that the present invention can be applied to a photovoltaic element in which pin structures such as a pinpin structure (double structure) and a pinpinpin structure (triple structure) are stacked. .

The photovoltaic element of the present invention is suitable as the top pin photovoltaic element on the light incident side of a photovoltaic element having a stacked pin structure. In the case of the double structure, as the bottom photovoltaic element, a photovoltaic element having a pin structure containing silicon as a main constituent element as an i-type layer, or i
As the mold layer, a photovoltaic element having a pin structure containing silicon and germanium as main constituent elements is suitable. Further, in the case of the triple structure, the middle photovoltaic element is a pin photovoltaic element having silicon as a main constituent element as an i-type layer, or a pin having silicon and germanium as a main constituent element as an i-type layer. Photovoltaic elements with a structure are suitable. As the bottom photovoltaic element of triple structure,
A photovoltaic element containing 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 using an RF plasma CVD method suitable for forming a deposited film of a photovoltaic element of the present invention. The manufacturing apparatus includes a deposition chamber 401, a gas introduction pipe 411, a substrate 404, a heater 405, a vacuum gauge 402, and a conductance valve 40.
7, auxiliary valve 408, leak valve 409, RF power supply 403, RF electrode 410, source gas supply device 2000,
Mass flow controllers 2011-2017, valves 2001-2007, 2021-2027, pressure regulators 2031-2037, raw material gas cylinders 2041-204
7 and the like.

FIG. 12 shows another example of a manufacturing apparatus suitable for forming a deposited film of a photovoltaic element of the present invention, using a microwave plasma CVD method. The manufacturing apparatus includes a deposition chamber 1201, a substrate 1204, a heater 12
05, vacuum gauge 1202, conductance valve 120
7, auxiliary valve 1208, leak valve 1209, RF
Power supply 1203, bias rod 1214, waveguide 1212,
It comprises a dielectric window 1213, a shutter 1215 and the like.

The details of the deposition mechanism of the i-type layer in the method of manufacturing a photovoltaic device according to the present invention are unknown, but are considered as follows.

Microwave energy lower than the microwave energy required to decompose the raw material gas by 100% is applied to the raw material gas, and R is higher than the microwave energy.
It is considered that by simultaneously applying F energy to the source gas, active species suitable for forming a deposited film can be selected. Further, when the internal pressure in the deposition chamber when the source gas is decomposed is set to 50 mTorr or less, the mean free path of 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. Further, it is considered that the RF energy has little effect on the decomposition of the source gas when the internal pressure in the deposition chamber is 50 mTorr or less, and controls the potential between the plasma in the deposition chamber and the substrate.

That is, in the case of the microwave plasma CVD method,
Although the potential difference between the plasma and the substrate is small, the potential difference between the plasma and the substrate (+ on the plasma side and − on the substrate side) can be increased by applying RF energy simultaneously with microwave energy. By increasing the plasma potential positively with respect to the substrate in this manner, active species decomposed by microwave energy are deposited on the substrate, and at the same time, + ions accelerated by the plasma potential collide with the substrate and collide with the substrate surface. It is considered that the relaxation reaction of is accelerated and a high-quality deposited film can be obtained. In particular, this effect becomes remarkable when the deposition rate is several nm / sec or more.

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

In addition, when depositing a layer with a changed band gap, the flow rate and flow rate ratio of the source gas change with time or spatially. It is necessary to change it appropriately.
However, in the method of forming a deposited film according to the present invention, the ratio of ions changes due to the temporal or spatial change of the flow rate and flow rate ratio of the source gas, and the RF self-bias is automatically adjusted accordingly. Change. As a result, when the source gas flow rate and the source gas flow rate ratio are changed by applying RF to the bias rod, the discharge becomes very stable as compared with the case of DC bias.

In addition, in the method of forming a deposited film according to the present invention, in order to obtain a desired change in band gap, a gas containing silicon atoms and a gas containing carbon atoms are supplied from the deposition chamber 5 times.
It is preferred to mix at a distance of less than m. 5m
If the source gases are mixed farther apart, even if the mass flow controller is controlled in response to a desired band gap change, the source gas mixing positions are far apart, so that the source gas change is delayed or the source gas is interdiffused. Occurs, resulting in a deviation from a desired band gap. That is, if the mixing positions of the source gases are too far apart, the controllability of the band gap is reduced.

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

Next, the deposited film forming method of the present invention will be described more specifically.

First, a substrate 404 for forming a deposited film is mounted in the deposition chamber 401 shown in FIG. 4 and the deposition chamber is sufficiently evacuated to the order of 10 ⁻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, if the internal pressure of the deposition chamber 401 becomes 10 ^-4 or less, H ₂ ,
A gas such as He, Ar, Ne, Kr, or Xe is preferably introduced into the deposition chamber. After exhausting the deposition chamber sufficiently, H
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 substantially equal to that when the source gas for forming the deposited film is flowed. The optimum pressure in the deposition chamber is 0.5 to 50 mTorr.

When the pressure in the deposition chamber is stabilized, the substrate heater 405 is turned on and the substrate is heated to 100 to 500 ° C.
Heat to When the temperature of the substrate is stabilized at a predetermined temperature, gases such as H ₂ , He, Ar, Ne, Kr, and Xe are stopped,
A predetermined amount of a raw material gas for forming a deposited film is introduced from a gas cylinder into a deposition chamber through a mass flow roller.
The supply amount of the source gas for forming the deposited film introduced into the deposition chamber is appropriately determined by the volume of the deposition chamber.
On the other hand, the internal pressure in the deposition chamber when a source gas for depositing a deposition film is introduced into the deposition chamber is a very important factor in the deposition film forming method of the present invention, and the optimal internal pressure in the deposition chamber is RF.
0.05 to 3 Torr for plasma CVD, 0.05 to 50 mTorr for microwave plasma CVD
It is.

In the method of forming a deposited film according to 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 to decompose the raw material gas by 100%. , 0.005 to 1 W / cm
³ A preferable frequency range of the 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, the stability of the frequency of microwave energy is very important. . Preferably, the frequency variation is in the range of ± 2%. Further, the ripple of the microwave is preferably in a range of ± 2%.

Further, in the method for forming a deposited film of the present invention, the RF energy supplied simultaneously with the microwave energy into the deposition chamber is a very important factor in combination with the microwave energy. The range is 0.01 to 2 W / cm ³ . RF
Is preferably 1 to 100 MHz. In particular, 13.56 MHz is optimal. Also R
The fluctuation of the frequency of F is within ± 2%, and the waveform is preferably a smooth waveform.

The supply of the RF energy is appropriately selected depending on the area ratio between the area of the bias rod for supplying the RF energy and the area of the ground. In particular, the area of the bias rod for supplying the RF energy is determined by the area of the ground. If the width is smaller than that, it is preferable to ground the self-bias (DC component) on the power supply side for supplying RF energy. Also, RF
When the self-bias (DC component) on the power supply side for supplying energy is not grounded, it is preferable that the area of the bias rod for supplying RF energy be larger than the area of the ground contacting the plasma.

Such microwave energy is introduced from the waveguide 1212 into the deposition chamber via the dielectric window 1213, and at the same time, RF energy is introduced from the RF power source 1203 into the deposition chamber via the bias rod (RF electrode) 1214. I do. In this state, the source gas is decomposed for a desired time to form a deposited film having a desired thickness on the substrate. Thereafter, the input of microwave energy and RF energy is stopped, the deposition chamber is evacuated, and sufficiently purged with a gas such as H ₂ , He, Ar, Ne, Kr, or Xe. Take out.

A DC voltage may be applied to the bias rod (RF electrode) 1214 in addition to the RF energy. It is preferable to apply the voltage so that the bias bar becomes positive as the polarity of the DC voltage.
The preferable range of the DC voltage is 10 to 30.
0V.

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, the following compounds are suitable.

For example, gaseous compounds containing silicon atoms include SiH ₄ , Si ₂ H ₆ , SiF ₄ and 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, Si ₂ D ₃ H _{3 and the} like can be mentioned.

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), and C ₂ H ₂ , C ₆ H ₆ , CO ₂ ,
CO and the like.

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

In the present invention, examples of the valence electron controlling agent introduced into the non-single-crystal semiconductor layer for controlling the valence electron of the non-single-crystal semiconductor layer include Group III atoms and Group V atoms of the periodic table. Can be B ₂ H ₆ , B ₄ H ₁₀ , B ₅ H ₉ , B ₅ H ₁₁ , B ₅
Borohydrides such as ₆ H ₁₀ , B ₆ H ₁₂ , B ₆ H ₁₄ , BF ₃ , B
And boron halide such as Cl ₃ . In addition, AlCl ₃ , GaCl ₃ , InCl ₃ , T
1Cl _{3 and the} like can also be mentioned.

The starting material for introducing a group V atom is effectively used. Specifically, for introducing a phosphorus atom, a hydrogenated phosphorus such as PH ₃ or P ₂ H ₄ , PH ₄ I, PF ₃ , P
Phosphorus halides such as F ₅ , PCl ₃ , PCl ₅ , PBr ₃ , PBr ₅ , PI _{3 and the} like 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
Cl ₃ , BiBr _{3 and the} like can also be mentioned.

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

The introduction amount of Group III atoms and Group V atoms of the periodic table introduced into the i-type layer of the non-single-crystal semiconductor layer is 1000.
ppm or less is mentioned as a preferable range. It is preferable to add the group III atom and the group V atom in the periodic table so that they are simultaneously compensated.

As the gas effectively used as a starting material for introducing a nitrogen atom or an oxygen atom in the i-type of the present invention, for example, a nitrogen atom-introduced gas includes N ₂ , NH ₃ , ND ₃ ,
NO, NO ₂ , N ₂ O, and the like. O ₂ , CO, CO ₂ , NO, NO ₂ , N ₂
O, CH ₃ CH ₂ OH, CH ₃ OH and the like.

As the deposition apparatus of the present invention, an apparatus in which a microwave plasma CVD apparatus and an RF plasma CVD apparatus are continuously connected is more preferable. It is preferable that the deposition chamber by the microwave plasma CVD method and the deposition chamber by the RF plasma CVD method are separated by a gate. As the gate, a mechanical gate valve, gas gate, or the like is suitable.

In the present invention, a layer (doping layer A) containing a Group III element and / or a Group V element as a main constituent element of the periodic table and a silicon atom containing a valence electron controlling agent as a main constituent element. Layer (dove layer B) and a p-type layer or an n-type layer having a laminated structure with the microwave plasma CV
It can be formed using a D apparatus or the RF plasma CVD apparatus.

The doving layer A is made of the above-mentioned periodic table II.
Using a gas containing a Group I element and / or a Group V element as a source gas, microwave plasma CVD or R
It is preferable to deposit by the F 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.

The doping layer B is also formed by mixing a Group III element and / or a Group V element of the periodic table with a silicon atom-containing gas as a valence electron controlling agent and depositing the mixture by microwave plasma CVD or RF plasma CVD. Is preferred.

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

The doping layer B containing a crystal phase is formed by RF
When depositing by a plasma CVD method, the silicon atom-containing gas is preferably diluted with hydrogen gas (H ₂ , D ₂ ) to 0.01 to 10%, and the RF power is preferably 1 to 10 W / cm ^2. Condition.

In the case where the p-type layer and / or the n-type layer of the photovoltaic device of the present invention is formed by laminating a doping layer A and a doping layer B, it is preferable that the p-type layer and / or the n-type layer start with the doping layer B and end with the doping layer B. Things. For example, BA
B, BABAB, BABABAB, BABABABAB
And the like are preferable.

In particular, 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, when the doping layer B is in contact with the transparent electrode, the period of indium oxide or tin oxide constituting the transparent electrode is higher. The diffusion of the Group III element and / or the Group V element in the rate table can be prevented, and the decrease over time in the photoelectric conversion efficiency of the photovoltaic element can be reduced.

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

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

Examples of the electrically insulating support include films or sheets of synthetic resins such as polyester, polyethylene, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, and polyamide; glass, ceramics, paper, and the like. Is mentioned. These electrically insulating supports preferably have at least one surface conductively treated,
It is desirable to provide a photovoltaic layer on the conductive-treated surface side.

For example, in the case of glass, N
iCr, Al, Cr, Mo, Ir, Nb, Ta, V, T
i, Pt, Pb, In ₂ O ₃ , ITO (In ₂ O ₃ + SnO
₂ ) The conductive property is imparted by providing a thin film composed of NiCr, Al, Ag, Pb, Zn, Ni, and the like.
Au, Cr, Mo, Ir, Nb, Ta, V, Tl, Pt
A thin metal film such as is provided on the surface by vacuum evaporation, electron beam evaporation, sputtering, or the like, or the surface is laminated with the metal to impart conductivity to the surface. The shape of the support may be a sheet having a smooth surface or an uneven surface. The thickness is 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 exhibited is provided. Can be made as thin as possible. However, the thickness is usually 10 μm or more from the viewpoints of production, handling, and mechanical strength of the support.

(Light Reflecting Layer) As the light reflecting layer, Ag, A
Metals with high reflectivity from visible light to near infrared, such as l, Cu, and AlSi, are suitable. 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. Suitable layer thicknesses of these metals as the light reflecting layer are 10 nm to 5000 nm. To texture these metals, the substrate temperature at the time of depositing these metals may be 200 ° C. or higher.

(Reflection Increasing Layer) As the reflection increasing layer, Zn was used.
O, SnO ₂ , In ₂ O ₃ , ITO, TiO ₂ , CdO, C
d ₂ SnO ₄ , Bi ₂ O ₃ , MoO ₃ , NaxWO _{3 and the} like are mentioned as the most suitable ones.

As a method for depositing the reflection increasing layer, a vacuum deposition method, a sputtering method, a CVD method, a spray method, a spin-on method, a dipping method, and the like are mentioned as suitable methods.

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

(P-type layer or n-type layer) The p-type layer or the n-type layer is an important layer that affects the characteristics of the photovoltaic element.

The amorphous material (denoted as a-) of the p-type layer or the n-type layer (microcrystalline material (denoted as μc-) is also included in the category of the amorphous material). 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., a p-type valence electron controlling agent (Periodic Table III
Polycrystalline materials include high-concentration materials containing group atoms B, Al, Ga, In, and Tl) and n-type valence electron control agents (group V atoms P, As, Sb, and Bi in the periodic table). (Poly
-) Is, 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 controlling agent (Group III atom B, Al,
Ga, In, Tl) and a material in which an n-type valence electron controlling agent (Group V atom P, As, Sb, Bi) in the periodic table is added at a high concentration.

In particular, 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 addition amount of Group III atoms in the periodic table to the p-type layer and the addition amount of Group V atoms in the periodic table to the n-type layer are 0.1 to 0.1.
50 at% is mentioned as the optimum amount.

Further, hydrogen atoms (H, D) or halogen atoms contained in the p-type layer or the n-type layer work to compensate for dangling bonds of the p-type layer or the n-type layer, and This is to improve 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 optimal amount of hydrogen atom or halogen atom is 0.1 to 8 at%. Further, a preferred distribution form is one in which a large content of hydrogen atoms and / or halogen atoms is distributed on each interface side of the p-type layer / i-type layer and the n-type layer / i-type layer. The content of the hydrogen atom and / or the halogen atom is preferably in a range of 1.1 to 2 times the content in the bulk. As described above, by increasing the content of hydrogen atoms or halogen atoms near each interface between the p-type layer / i-type layer and the n-type layer / i-type layer, defect levels and mechanical strain near the interface are reduced. Accordingly, the photovoltaic power and the photocurrent of the photovoltaic device of the present invention can be increased.

The electrical characteristics of the p-type layer and the n-type layer of the photovoltaic element are preferably those having an activation energy of 0.2 eV or less, and most preferably those having an activation energy of 0.1 eV or less. The specific resistance is preferably 100 Ωcm or less, and most preferably 1 Ωcm or less. Further, the layer thickness of the p-type layer and the n-type layer is 1 to
50 nm is preferred, and 3 to 10 nm is optimal.

As a source gas suitable for depositing a p-type layer or an n-type layer of a photovoltaic element, a gasizable compound containing a silicon atom, a gasizable compound containing a germanium atom, and a carbon atom were used. Examples thereof include a compound that can be gasified, and a mixed gas of the compound.

Specific examples of the gasizable compounds containing silicon atoms 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 , 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 gasizable 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 and the like.

Materials introduced into the p-type layer or the n-type layer for controlling valence electrons include those of Group III and V of the periodic table.
Group atoms.

As a substance 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, BC
and boron halides such as l ₃ .
In addition, AlCl ₃ , GaCl ₃ , InCl ₃ , TIC
l ₃ and the like can also be mentioned. Particularly, B ₂ H ₆ and BF ₃ are suitable.

Effectively used as a starting material for introducing a group V atom is, specifically, PH for introducing a phosphorus atom.
₃ , hydrogenated phosphorus such as P ₂ H ₄ , PH ₄ I, PF ₃ , PF ₅ , PC
and 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 and the} like can also be mentioned. Particularly, PH ₃ and PF ₃ are suitable.

The compounds capable of being gasified are H ₂ , H
The gas 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 element is an RF plasma CVD method or a microwave plasma CVD method. In particular, when depositing by RF plasma CVD, a capacitively coupled RF plasma CVD is suitable.

When a p-type layer or an n-type layer is deposited by RF plasma CVD, the substrate temperature in the deposition chamber is 100 to 3
50 ° C., internal pressure: 0.1 to 10 Torr, RF power: 0.01 to 5.0 W / cm ² , deposition rate: 0.1
-30 A / sec is mentioned as an optimum condition.

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

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

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

When a p-type layer or an n-type layer is deposited by microwave plasma CVD 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 is 0.005 to 1 W / c
The frequency of the m ³ microwave is preferably in the range of 0.5 to 10 GHz.

In particular, when depositing a layer having a small light absorption or a wide band gap 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) In the photovoltaic element, the i-type layer is an important layer for generating and transporting carriers with respect to irradiation light.

As the i-type layer, a slightly p-type or slightly n-type layer can be used. The i-type layer of the photovoltaic element of the present invention contains silicon atoms and carbon atoms and is an i-type layer. The band gap changes smoothly in the thickness direction of the layer, and the local minimum value of the band gap is shifted from the center of the i-type layer toward the interface between the p-type layer and the i-type layer. In the i-type layer, a layer in which a valence electron controlling agent serving as a donor and a valence electron controlling agent serving as an acceptor are simultaneously doped is more suitable.

The hydrogen atoms (H, D) or the halogen atoms (X) contained in the i-type layer work to compensate for dangling bonds of the i-type layer, and the carrier mobility and lifetime of the carrier in the i-type layer. To improve the product of Also, p-type layer / i-type layer, n-type layer /
It works to compensate for the interface state of each interface of the i-type layer, and has the effect of improving the photovoltaic power, photocurrent and photoresponsiveness of the photovoltaic element. The optimal content of hydrogen atoms and / or halogen atoms contained in the i-type layer is 1 to 40 at%.

In particular, those having a large content of hydrogen atoms and / or halogen atoms at each interface side of the p-type layer / i-type layer and the n-type layer / i-type layer are mentioned as preferred distribution modes. The preferred range of the content of hydrogen atoms and / or halogen atoms in the vicinity of the interface is 1.1 to 2 times the content in the bulk. Further, it is preferable that the content of hydrogen atoms and / or halogen atoms is changed in a direction opposite to the direction in which the content of silicon atoms is increased or decreased. The content of hydrogen atoms and / or halogen atoms where the content of silicon atoms is the minimum is preferably in the range of 1 to 10 at%, and the maximum range of the content of hydrogen atoms and / or halogen atoms is 0.3 to 0. Eight times is a preferred range.

The content of hydrogen atoms and / or halogen atoms is changed in a direction opposite to the direction of change in the content of silicon atoms, that is, corresponding to the band gap, the hydrogen atoms and / or halogen atoms are narrow at a narrow band gap. The atomic content is low. Although the details of the mechanism are unknown, according to the method for forming a deposited film of the present invention, in the deposition of an alloy semiconductor containing silicon atoms and carbon atoms, each of them depends on the difference in the ionization rate of silicon atoms and carbon atoms. It is considered that there is a difference in the energies obtained by the atoms, and as a result, even if the hydrogen content or / halogen content in the alloy-based semiconductor is small, the relaxation is sufficiently advanced and a good-quality alloy-based semiconductor can be deposited.

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

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

The thickness of the i-type layer greatly depends on the structure of the photovoltaic element (for example, single cell, tandem cell, triple cell) and the band gap of the i-type layer.
1.0 μm is mentioned as the optimum layer thickness.

The i-type layer containing silicon atoms and carbon atoms according to the method of forming a deposited film of the present invention has a deposition rate of 2.5 n.
Even if the speed is increased to m / sec or more, the tail state on the valence band side is small, and the tilt of the tail state is 60 m.
It is not more than eV, and the density of dangling bonds by electron spin resonance (esr) is not more than 10 ¹⁷ / cm ³ .

The band gap of the i-type layer is p-type layer / i
It is preferable to design so as to be wider on each interface side of the mold layer and the n-type layer / i-type layer. With such a design, the photovoltaic power and the photocurrent of the photovoltaic element can be increased, and furthermore, it is possible to prevent light deterioration or the like when used for a long time.

(Transparent Electrode) As the transparent electrode, a transparent electrode of indium oxide or indium oxide is suitable.

A transparent electrode is deposited as follows.
For deposition of the transparent electrode, a sputtering method and a vacuum deposition method are the most suitable deposition methods.

When a transparent electrode made of indium oxide is deposited on a substrate in a magnetron sputtering apparatus, a target such as metal indium (In) or indium oxide (In ₂ O ₃ ) is used. When a transparent electrode made of indium tin oxide is deposited on a substrate, the target is metal tin (S
n), a target such as an alloy of metal indium or metal tin and metal indium, a tin oxide, an indium oxide, an indium tin oxide or the like is used in an appropriate combination.

When depositing by sputtering, the substrate temperature is an important factor, and a preferred range is from 25 ° C. to 600 ° C. Examples of the sputtering gas include an inert gas such as an argon gas (Ar), a neon gas (Ne), a xenon gas (Xe), and a helium gas (He). In particular, an Ar gas is optimal. It is preferable to add oxygen gas (O ₂ ) to the inert gas as needed. Particularly when a metal is targeted, oxygen gas (O ₂ ) is essential.

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

As a power source, a DC power source and an RF power source are suitable. A suitable range for the electric power during sputtering is 10 to 1000 W.

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

The deposition source suitable for depositing the transparent electrode in the vacuum deposition method includes metal tin, metal indium,
An indium alloy is used. A suitable temperature range of the substrate when depositing the transparent electrode is in the range of 25 ° C. to 600 ° C.

Further, when depositing a transparent electrode, the pressure of the deposition chamber was reduced to the order of 10 ⁻⁶ Torr or less, and then oxygen gas (O ₂ )
Must be introduced into the deposition chamber in the range of 5 × 10 ⁻⁵ Torr to 9 × 10 ⁻⁴ Torr. By introducing oxygen in this range, the metal vaporized from the evaporation source reacts with oxygen in the gas phase to deposit a good transparent electrode.

Further, plasma may be generated by introducing RF power at the above-mentioned degree of vacuum, and vapor deposition may be performed via the plasma. The preferable range of the deposition rate of the transparent electrode under the above conditions is 0.01 to 10 nm / sec. When the deposition rate is less than 0.01 nm / sec, the productivity is reduced. When the deposition rate is more than 10 nm / sec, the film becomes a coarse film, and the transmittance, the conductivity and the adhesion are reduced.

Next, the power generation system of the present invention will be described.
The power generation system of the present invention provides the above-described photovoltaic element of the present invention and the power supplied from the photovoltaic element to the storage battery and / or the 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 power supplied from the photovoltaic element and / or supplying the power to an external load.

FIG. 16 shows an example of a power supply system according to the present invention, which is a basic circuit for charging and supplying power using a photovoltaic element. In this circuit, the photovoltaic element of the present invention is used as a solar cell module, and a backflow prevention diode (C
D), a voltage control circuit (constant voltage circuit) for monitoring the voltage and controlling the voltage, a storage battery, a load, and the like.
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, and the like.

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 control IC stops the charging current.

A solar cell system utilizing such photovoltaic power can be used as a power source for a battery charging system for a car, a battery charging system for a ship, a streetlight lighting system, an exhaust system, and the like.

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

[0142]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

Example 1 In this example, a solar cell was manufactured in which P and B atoms were introduced into the i-type layer, and each of the p and n-type layers had a single-layer structure.

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

Next, the source gas supply device 200 shown in FIG.
A semiconductor layer was formed on the reflection-enhancing layer by a manufacturing apparatus using a glow discharge decomposition method, which includes a deposition apparatus 400 and a glow discharge decomposition method.

The gas cylinders 2041 to 2047 in the figure are sealed with a source gas for producing the photovoltaic element of the present invention, and 2041 is a SiH ₄ gas (purity 99.
999%) cylinder, 2042 is CH ₄ gas (purity: 99.99%).
9999%) cylinder, 2043 is H ₂ gas (purity 99.99%).
9999%) cylinder, 2044 is 100pp with H ₂ gas
m3, a PH ₃ gas (purity 99.99%, hereinafter abbreviated as “PH ₃ / H ₂ ”) cylinder, and 2045 a B ₂ H ₆ gas (purity 99.99%) diluted with H ₂ gas to 100 ppm.
99%, hereinafter abbreviated as “B ₂ H ₆ / H ₂ ”)
046 is NH ₃ gas (purity 9) diluted to 1% with H ₂ gas.
9.9999%, hereinafter abbreviated as "NH ₃ / H ₂ ") cylinder, 2047 is O ₂ gas (purity 99.9999%, hereinafter abbreviated as “O ₂ / He”) diluted to 1% with He gas. ) It is a cylinder. In advance, gas cylinders 2041 to 204
7 when installing each gas,
Introduced into the gas pipe up to 2027, the pressure regulator 203
Each gas pressure was adjusted to ² kg / cm ² by 1 to 2037. The SiH ₄ gas and the CH ₄ gas are m from the deposition chamber.
And mixed.

Next, the back surface of the substrate 404 on which the reflection layer and the reflection enhancement layer are formed is brought into close contact with the heater 405,
The leak valve 409 of the deposition chamber 401 is closed, the conductance valve 407 is fully opened, the interior of the deposition chamber 401 is evacuated by a vacuum pump (not shown), and the 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.
When the pressure reached Torr, valves 2001 to 2007 were closed, and 2031 to 2037 were gradually opened to introduce the respective gases into mass flow controllers 2011 to 2017.

After the preparation for film formation was completed as described above, n-type, i-type, and p-type semiconductor layers were formed on the substrate 404.

To form the n-type layer, the valve 2003 is gradually opened, H ₂ gas is introduced into the deposition chamber 401 through the gas introduction pipe 411, and the mass flow controller 2013 is set so that the H ₂ gas flow rate becomes 50 sccm. Adjusted with. The conductance valve is adjusted while watching the vacuum gauge 402 so that the pressure in the deposition chamber becomes 1.0 Torr, and the heater 4 is adjusted so that the temperature of the substrate 404 becomes 270 ° C.
05 was set.

When the substrate was sufficiently heated, the valves 2001 and 2004 were gradually opened, and SiH ₄ gas and PH ₃ / H ₂ gas were introduced into the deposition chamber 401. At this time, the flow rate of the SiH ₄ gas is ₂ sccm, and the flow rate of the H ₂ gas is 1
Each of the mass flow controllers 2011 and 20 is controlled so that the flow rate of the PH ₃ / H ₂ gas is 20 sccm.
13, 2014. The pressure in the deposition chamber 401 is
The opening of the conductance valve 407 was adjusted while watching the vacuum gauge 402 so that the pressure became 1.0 Torr. The power of the RF power source was set to 7 mW / cm ³ , and RF power was introduced into a discharge space 406 surrounded by the RF electrode 410 to generate glow discharge. When the n-type layer having a thickness of 20 nm was produced, the RF power was turned off, glow discharge was stopped, and the formation of the n-type layer was completed. By closing the valves 2001 and 2004, the S
iH ₄ gas, stopping the flow of PH ₃ / H ₂ gas for 5 minutes, after which continued to flow deposition chamber 401 in F H ₂ gas, closing the outlet valves 2003, was evacuated deposition chamber 401 and the gas pipes .

Next, to produce an i-type layer, the valve 20
03 was gradually opened, H ₂ gas was introduced into the deposition chamber 401, and the mass flow controller 2013 adjusted the H ₂ gas flow rate to 50 sccm. The conductance valve was adjusted while watching the vacuum gauge 402 so that the pressure in the deposition chamber became 1.5 Torr.
The heater 405 was set to 50 ° C., and when the substrate was sufficiently heated, the valves 2001 and 20 were further heated.
02, 2004 and 2005 were gradually opened, and SiH ₄ gas, CH ₄ gas, PH ₃ / H ₂ gas and B ₂ H ₆ / H ₂ gas were flowed into the deposition chamber 401. At this time, the flow rate of the SiH ₄ gas is 10 sccm, the flow rate of the CH ₄ gas is ₃ sccm, the flow rate of the H ₂ gas is 100 sccm, and the flow rate of the PH ₃ / H ₂ gas is 0.2 sccm.
cm and the flow rate of the B ₂ H ₆ / H ₂ gas were adjusted to 0.5 sccm with each mass flow controller. The opening of the conductance valve 407 was adjusted while watching the vacuum gauge 402 so that the pressure in the deposition chamber 401 became 1.5 Torr. Set the RF power to 70 mW / cm ³ ,
Power is introduced to cause glow discharge in the discharge space 406,
When the formation of the i-type layer on the n-type layer was started, the flow rates of the SiH ₄ gas and the CH ₄ gas were changed according to the flow rate change pattern shown in FIG. 5 using a computer connected to the mass flow controller.

When the i-type layer having a thickness of 300 nm was produced, the RF power was turned off, glow discharge was stopped, and the production of the i-type layer was completed. Valves 2001, 2002, 2004, 20
05, and SiH ₄ gas, CH ₄ into the deposition chamber 401.
After stopping the flow of the gas, PH ₃ / H ₂ gas, and B ₂ H ₆ / H ₂ gas, the H ₂ gas is kept flowing into the deposition chamber 401 for 5 minutes. The inside of the gas pipe was evacuated.

[0153] 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 inside the deposition chamber is 2.0
The conductance valve is adjusted while watching the vacuum gauge 402 so as to reach Torr, and the heater 405 is set so that the temperature of the substrate 404 becomes 200 ° C. When the substrate is sufficiently heated, the valves 2001, 2002, and 2 are further provided.
005 is gradually opened, and 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 was adjusted so that the gas flow rate became 100 sccm. The opening of the conductance valve 407 was adjusted while watching the vacuum gauge 402 so that the pressure in the deposition chamber 401 became 2.0 Torr.

The RF power was set to 200 mW / cm ³ ,
RF power was introduced to generate a discharge space 406 and glow discharge, and the formation of a p-type layer on the i-type layer was started. Layer thickness 10nm
When the p-type layer was manufactured, the RF power was turned off, glow discharge was stopped, and the formation of the p-type layer was completed. Valve 2001,
2002 and 2005 are closed, and the Si
Stop inflow of H ₄ gas, CH ₄ gas, B ₂ H ₆ / H ₂ gas,
After continuously flowing H ₂ gas into the deposition chamber 401 for 5 minutes,
The valve 2003 was closed, the inside of the deposition chamber 401 and the gas pipe were evacuated, 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 thickness of 80 nm as a transparent electrode and chromium (Cr) having a thickness of 10 μm as a current collecting electrode were deposited on the p-type layer by a normal vacuum deposition method. did. Thus, the fabrication 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 layer, and the p-type layer.

<Comparative Example 1-1> In 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 in accordance with the flow rate patterns shown in FIG. 6, the same conditions and the same procedure as in Example 1 were used to form a reflective layer, a reflection increasing layer, n-type layer, i-type layer, p-type layer,
A transparent electrode and a current collecting electrode were formed to produce a solar cell. This solar cell is referred to as (SC ratio 1-1).

<Comparative Example 1-2> When forming an i-type layer,
A method similar to that of Example 1 except that no H ₃ / H ₂ gas was flowed,
In the same manner, a reflection layer, a reflection enhancement layer, an n-type layer,
A solar cell was manufactured by forming an i-type layer, a p-type layer, a transparent electrode, and a current collecting electrode. This solar cell is referred to as (SC ratio 1-2).

<Comparative Example 1-3> When forming an i-type layer,
Similar methods except that no shed ₂ H ₆ / H ₂ gas as in Example 1, the same on the substrate in step, the reflective layer, the reflection enhancing layer, n-type layer, i-type layer, p-type layer, a transparent electrode, A current collecting electrode was formed to produce a solar cell. This solar cell is referred to as (SC ratio 1-3).

<Comparative Example 1-4> In forming the i-type layer,
A reflection layer, a reflection enhancement layer, an n-type layer, and an i-type layer were formed on a substrate under the same conditions and in the same procedure as in Example 1 except that the PH ₃ / H ₂ gas and the B ₂ H ₆ / H ₂ gas were not supplied. , P-type layer, transparent electrode,
A current collecting electrode was formed to produce a solar cell. This solar cell is referred to as (SC ratio 1-4).

The fabricated solar cells (SC Ex. 1) and (SC
The measurement of the initial photoelectric conversion efficiency (photovoltaic power / incident optical power) and durability characteristics of the ratios 1-1) to (SC ratio 1-4) were performed.

The initial photoelectric conversion efficiency was determined by installing the solar cell under AM-1.5 (100 mW / cm ² ) light irradiation and measuring VI characteristics.

As a result of the measurement, the initial photoelectric conversion efficiencies of (SC ratio 1-1) to (SC ratio 1-4) for the solar cell of (SC actual 1) were as follows.

(SC ratio 1-1) 0.92 times (SC ratio 1-2) 0.91 times (SC ratio 1-3) 0.90 times (SC ratio 1-4) 0.90 times The manufactured solar cell was subjected to a humidity of 70% and a temperature of 6%.
AM1.5 (100 mW / c) after being set in a dark place at 0 ° C. and subjected to vibration of 3600 rpm and amplitude of 1 mm for 24 hours.
m ² ) Evaluation was made based on a decrease in photoelectric conversion efficiency under irradiation (photoelectric conversion efficiency after endurance test / initial photoelectric conversion efficiency).
As a result of the measurement, for the solar cell of (SC Ex. 1), (SC
The reduction in the photoelectric conversion efficiency in the ratios 1-1) to (SC ratio 1-4) was as follows.

(SC ratio 1-1) 0.92 times (SC ratio 1-2) 0.91 times (SC ratio 1-3) 0.90 times (SC ratio 1-4) 0.92 times A stainless steel substrate and a barium borosilicate glass (7059 manufactured by Corning Incorporated) substrates were used, and the flow rates of SiH ₄ gas and CH ₄ gas were set to the values shown in Table 2, except that:
Under the same manufacturing conditions as for the i-type layer of Example 1, an i-type layer was formed at 1 μm 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 manufactured sample for physical property measurement were analyzed, and the relationship between the composition ratio of Si (silicon) atoms and C (carbon) atoms and the bandgap was determined. Table 2 and FIG. 7 show the band gap and the results of the composition analysis.

Here, the band gap was measured by using a glass substrate on which an i-type layer had been prepared by using a spectrophotometer (manufactured by Hitachi, Ltd.).
30 type), the wavelength dependence of the absorption coefficient of the i-type layer was measured, and the i-type layer was measured according to the method described in p. The band gap of the layer was determined. In the composition analysis, the stainless substrate on which the i-type layer was formed was placed in an Auger electron spectrometer (JAMP-3, manufactured by JEOL Ltd.), and Si atoms and C
The atomic composition ratio was measured.

Next, the fabricated solar cell (SC Ex. 1)
The composition analysis of Si atoms and C atoms in the layer thickness direction in the i-type layers (SC ratio 1-1) to (SC ratio 1-4) was performed in the same manner as the above-described composition analysis.

From the relationship between the composition ratio of Si atoms and C atoms and the band gap determined by (SP1-1) to (SP1-7), the change of the band gap in the thickness direction of the i-type layer was determined. FIG. 8 shows the result. As can be seen from FIG. 8, (S
In the solar cells of C Ex 1) and (SC ratio 1-2) to (SC ratio 1-4), the position of the minimum value of the band gap is shifted toward the p / i interface direction from the center position of the i-type layer. , (SC ratio 1-1), it was found that the position of the minimum value of the band gap was shifted toward the n / i interface from the center position of the i-type layer.

As described above, (SC actual 1), (SC ratio 1-1)
The change in the band gap in the layer thickness direction (SC ratio 1-4) is caused by the flow of the source gas containing Si (in this case, SiH ₄ gas) and the source gas containing C (in this case, CH ₄ ) It turns out that it depends on the ratio.

Next, the solar cell (SC actual 1), (SC ratio 1)
-1) to P atom and B in the i-type layer of (SC ratio 1-4)
The composition analysis of atoms in the layer thickness direction was performed using a secondary ion mass spectrometer (IMS-3F manufactured by CAMECA). As a result of the measurement, P atoms and B atoms were uniformly distributed in the layer thickness direction, and the composition ratio was as follows.

(SC Ex. 1) P / (Si + C) ３3 ppm B / (Si + C) 〜１０10 ppm (SC ratio 1-1) P / (Si + C) ３3 ppm B / (Si + C) 〜 10 ppm (SC ratio 1-2) P / (Si + C) DB / (Si + C) -10 ppm (SC ratio 1-З) P / (Si + C) ３3 ppm B / (Si + C) D. (SC ratio 1-4) P / (Si + C) D. B / (Si + C) N. D. N. D. As described in <Comparative Example 1-1> to <Comparative Example 1-4>, the solar cell (SC Ex. 1) of the present invention is different from the conventional solar cell (SC ratio 1-1) to (SC ratio 1-4) It was found that it had more excellent characteristics, and the effect of the present invention was proved.

Example 2 In Example 1, several solar cells were manufactured 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. Example 1 Photoelectric conversion efficiency and durability characteristics
Was examined in the same manner as described above. At this time, it was the same as Example 1 except for the change pattern of the SiH ₄ gas flow rate and the CH ₄ gas flow rate of the i-type layer.

FIG. 9 shows the band gap in the layer thickness direction of the solar cell when the change pattern of the flow rate of the SiH ₄ gas and the flow rate of the CH ₄ gas is changed. (SC Ex. 2-1) to (SC Ex. 2-5) are obtained by changing the position of the minimum value of the band gap in the layer thickness direction.
According to 5), it is changed from the p / i interface to the n / i interface. (SC Ex 2-6), (SC Ex 2-
7) is obtained by changing the minimum value of the band gap of (SC Ex. 2-1). (SC actual 2-8)-(SC actual 2
-10) is obtained by changing the change pattern. Table 3 shows the results of examining the initial photoelectric conversion efficiency and durability characteristics of these manufactured solar cells. Here, each value is (S
This is standardized based on C Ex 2-1).

As can be seen from these results, irrespective of the magnitude and change pattern of the minimum value of the band gap, i
The band gap of the mold layer changes smoothly in the layer thickness direction,
It has been found that the solar cell of the present invention, in which the position of the minimum value of the band gap is closer to the p / i interface direction than the position of the center of the i-type layer, exhibits better characteristics.

Example 3 In Example 1, several solar cells were produced in which the concentration and type of the valence electron controlling agent in the i-type layer were changed, and the initial photoelectric conversion efficiency and durability were the same as in Example 1. In a particular way. At this time, the procedure was the same as in Example 1 except that the concentration and type of the valence electron controlling agent in the i-type layer were changed.

[0176] <Example 3-1> i-type layer of the acceptor become valence electron controlling agent for the gas (B ₂ H ₆ / H ₂ gas) flow rate to 1/5, the total flow rate of H ₂ Example When a solar cell (SC Ex. 3-1) identical to that of Example 1 was fabricated, (S
Similar to C Ex 1), the conventional solar cell (SC ratio 1-1)-
It was found to have better initial photoelectric conversion efficiency and durability than (SC ratio 1-4).

<Example 3-2> The flow rate of the gas (B ₂ H ₆ / H ₂ gas) for the valence electron controlling agent serving as the acceptor of the i-type layer was increased by five times, and the total H ₂ flow rate was the same as in Example 1. When the same solar cell (SC Ex 3-2) was manufactured, similar to (SC Ex 1), the conventional solar cells (SC ratio 1-1) to (SC
It was found to have better initial photoelectric conversion efficiency and durability than the ratio 1-4).

<Example 3-3> The flow rate of the gas (PH ₃ / H ₂ gas) for the valence electron controlling agent serving as the donor of the i-type layer was increased by five times, and the total H ₂ flow rate was the same as in Example 1. When a solar cell (SC Ex. 3-3) was manufactured, similar to (SC Ex. 1), conventional solar cells (SC ratio 1-1) to (SC ratio 1-) were obtained.
It was found to have better initial photoelectric conversion efficiency and durability than 4).

<Example 3-4> The flow rate of the gas (PH ₃ / H ₂ gas) for the valence electron controlling agent serving as the donor of the i-type layer was reduced to 1/5, and the total H ₂ flow rate was the same as in Example 1. When the same solar cell (SC Ex. 3-4) was manufactured, (SC Ex. 1)
Similarly to conventional solar cells (SC ratio 1-1) to (SC ratio 1)
4) It was found to have better initial photoelectric conversion efficiency and durability characteristics than those of (4).

<Example 3-5> Instead of B ₂ H ₆ / H ₂ gas as a gas for a valence electron controlling agent serving as an acceptor of an i-type layer, trimethyl aluminum (A
1 (CH ₃ ) ₃ , abbreviated as TMA). At this time, the same method and procedure as in Example 1 are used, except that TMA (purity 99.99%) sealed in a liquid cylinder is gasified by bubbling with hydrogen gas and introduced into the deposition chamber 401. Solar cell (SC actual 3-5)
Was prepared. At this time, the flow rate of the TMA / H ₂ gas is 10
sccm. The manufactured solar cell (SC Ex. 3-5) is the same as the conventional solar cell (SC Comp. 1-1) as in (SC Ex. 1).
It was found to have better initial photoelectric conversion efficiency and durability than (SC ratio 1-4).

<Example 3-6> A solar cell using hydrogen sulfide (H ₂ S) gas instead of PH ₃ / H ₂ gas as a valence electron control agent gas serving as a donor of an i-type layer was manufactured. . The NH ₃ / H ₂ gas cylinder of Example 1 was hydrogenated (H ₂ ) to 100
H ₂ S gas diluted to ppm (purity 99.999%,
(Hereinafter abbreviated as “H ₂ S / H ₂ ”) and replaced with a cylinder, and using the same method and procedure as in Example 1, the solar cell (SC
Example 3-6) was produced. At this time, the flow rate of the H ₂ S / H ₂ gas was set at 1 sccm, and the other conditions were the same as in Example 1. The fabricated solar cell (SC Ex. 3-6) is (SC Ex. 1)
Similarly to conventional solar cells (SC ratio 1-1) to (SC ratio 1)
4) It was found to have better initial photoelectric conversion efficiency and durability characteristics than those of (4).

Example 4 A solar cell was manufactured in which the order of lamination of the n-type layer and the p-type layer was reversed. Table 4 shows the p-type layer, the i-type layer,
The conditions for forming the n-type layer will be described. When forming the i-type layer, Si
The flow rates of the H ₄ gas and the CH ₄ gas were changed as shown in the pattern of FIG. 6 so that the minimum value of the band gap came from the p / i interface. The layers other than the semiconductor layer and the substrate were as described in Example 1.
It was produced under the same conditions and using the same method. The manufactured solar cell (SC Ex. 4) has better initial photoelectric conversion efficiency and durability than conventional solar cells (SC Comp. 1-1) to (SC Comp. 1-4), similarly to (SC Ex. 1). It was found to have.

<< Embodiment 5 >> In the vicinity of the p / i interface of the i-type layer, i
A non-single-crystal silicon carbide solar cell having a maximum value of the band gap of the mold layer and a thickness of the region of 20 nm was produced. Table 5 shows the conditions for forming the n-type layer, the i-type layer, and the P-type layer, and FIG. 10A shows the flow rate change pattern of the i-type layer.
The layers other than the semiconductor layer and the substrate were manufactured under the same conditions and the same method as in Example 1.

Next, the composition analysis of the solar cell was performed in the same manner as in Example 1, and the change in the band gap in the thickness direction of the i-type layer was examined based on FIG. The result was as follows.

The manufactured solar cell (SC Ex. 5) was similar to the conventional solar cell (SC ratio 1-1) to (SC ex.
It was found to have better initial photoelectric conversion efficiency and durability than the ratio 1-4).

<Comparative Example 5> There is a region having a maximum band gap near the p / i interface of the i-type layer, and several non-single-crystal silicon carbide solar cells in which the thickness of the region is varied are manufactured. did. Except for the thickness of the region, it was manufactured using the same conditions and the same method as in Example 5.

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

Example 6 A non-single-crystal silicon carbide solar cell having a region having a maximum band gap near the n / i interface of the i-type layer and having a thickness of 15 nm was manufactured. Table 6 shows the conditions for forming the n-type layer, the i-type layer, and the p-type layer. FIG.
3 is shown. Except for the semiconductor layer and the substrate, the same conditions and the same method 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 examined based on FIG.
The result was as shown in FIG.

The manufactured solar cell (SC Ex. 6) is the same as the conventional solar cell (SC-1-1) to (S
C ratio was found to have better initial photoelectric conversion efficiency and endurance characteristics than 1-4).

<Comparative Example 6> There is a region having a maximum band gap near the n / i interface of the i-type layer, and some non-single-crystal silicon carbide solar cells in which the thickness of the territory is variously changed are described. Produced. Except for the thickness of the region, it was manufactured using the same conditions and the same method as in Example 6.

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

Example 7 A non-single-crystal silicon carbide solar cell in which a valence electron controlling agent was distributed in an i-type layer was manufactured.
FIG. 11A shows a change pattern of the flow rates of the PH ₃ / H ₂ gas and the B ₂ H ₆ / H ₂ gas. At the time of fabrication, the same conditions, the same method, and the same procedure as in Example 1 were used except that the flow rates of PH ₃ / H ₂ gas and B ₂ H ₆ / H ₂ gas were changed. The manufactured solar cell (SC Ex. 7) has better initial photoelectric conversion efficiency and durability characteristics than the conventional solar cells (SC Comp. 1-1) to (SC Comp. 1-4), similarly to (SC Ex. 1). It was found to have.

The change in the thickness direction of P atoms and B atoms contained in the i-type layer in the layer thickness direction was measured using a secondary ion mass spectrometer (SIM).
When examined using S), as shown in FIG.
It was found that at the position where the band gap was minimum, the contents of P atoms and B atoms were minimum.

Example 8 A non-single-crystal silicon carbide solar cell having an i-type layer containing oxygen atoms was manufactured. 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 manufactured solar cell (SC Ex. 8) is similar to (SC Ex. 1).
It was found that the solar cell had better initial photoelectric conversion efficiency and durability than conventional solar cells (SC ratio 1-1) to (SC ratio 1-4). Further, when the content of oxygen atoms in the i-type layer was determined by SIMS, it was found that the content was almost uniform.
It was found to be × 10 ¹⁹ (pieces / cm ³ ).

Example 9 A non-single-crystal silicon carbide solar cell having an i-type layer containing nitrogen atoms was manufactured. When forming the i-type layer, 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 manufactured solar cell (SC Ex. 9) has better initial photoelectric conversion efficiency and durability characteristics than the conventional solar cells (SC Comp. 1-1) to (SC Comp. 1-4), similarly to (SC Ex. 1). It was found to have.

Further, the content of nitrogen atoms in the i-type layer is determined by SI
As a result of examination by MS, it was contained almost uniformly, and 3 × 10 ¹⁷
(Pieces / cm ³ ).

Example 10 A non-single-crystal silicon carbide solar cell having an i-type layer containing oxygen atoms and nitrogen atoms was manufactured. When forming the i-type layer, the same conditions as in Example 1 except that O ₂ / He gas is introduced at 5 sccm, NH ₃ / H ₂ gas is introduced at 5 sccm, and the gas is introduced into the deposition chamber 401 in addition to the gas flowing in Example 1. The same method and the same procedure were used. The produced solar cell (SC Ex. 10) has better initial photoelectric conversion efficiency and durability than the conventional solar cells (SC Comp. 1-1) to (SC Comp. 1-4), similarly to (SC Ex. 1). It was found to have. When the contents of oxygen atoms and nitrogen atoms in the i-type layer were measured by SIMS, they were almost uniformly contained, each being 1 × 10 ¹⁹ (pieces / cm ³ ) and 3 × 10 ¹⁷
(Pieces / cm ³ ).

<Embodiment 11> In this embodiment, P and B atoms are introduced into an i-type layer by a deposition apparatus using a microwave plasma method shown in FIG. A solar cell having the structure shown in FIG. 1 was produced. When forming the i-type layer, the microwave plasma CVD method of the present invention was used.

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

Next, an n-type layer, an i-type layer, and a p-type layer, which are semiconductor layers, were sequentially formed on the reflection increasing layer.

The procedure is described below. First, the deposition apparatus shown in FIG. 4 is separated from the source gas supply apparatus at the auxiliary valve, and the deposition apparatus shown in FIG. 12 and the source gas supply apparatus shown in FIG. 4 are connected and used. Preparations have been completed.

To form the n-type layer, the heater 1205 is set so that the temperature of the substrate 1204 is 380 ° C., the flow rate of H ₂ gas is 300 sccm into the deposition chamber, and the pressure is 10 mTorr. Vacuum gauge 1202
Was adjusted with the conductance valve while watching. When the substrate was sufficiently heated, the flow rate of the SiH ₄ gas was 100 sc.
cm, a H ₂ gas flow rate of 100 sccm, and a PH ₃ / H ₂ gas flow rate of 300 sccm were introduced into the deposition chamber 1201. The opening of the conductance valve 1207 was adjusted so that the pressure in the deposition chamber 1201 was 30 mTorr. After confirming that the shutter 1215 is closed, the power of the μW power supply (not shown) is set to 0.10 W / cm ³ , and the waveguide, the waveguide 1212 and the dielectric window 1 (not shown) are set.
213, a μW power is introduced into the deposition chamber 1201,
A glow discharge was generated, and the shutter was opened to start forming an n-type layer on the reflection increasing layer. When the n-type layer having a thickness of 40 nm was formed, the shutter was closed, the power was turned off, the glow discharge was stopped, and the formation of the n-type layer was completed. The valves 2001 and 2004 are closed, and the Si
H ₄ gas, stopping the flow of PH ₃ / H ₂ gas for 5 minutes, after which continued to flow deposition chamber 1201 in F H ₂ gas, closing the outlet valves 2003, was evacuated deposition chamber and gas pipe 1201 .

To form an i-type layer, a heater is set so that the temperature of the substrate 1204 becomes 350 ° C., H ₂ gas is introduced into the deposition chamber at 300 sccm, and the pressure is 10
The opening of the conductance valve was adjusted to mTorr. When the substrate is heated sufficiently, SiH ₄ 100 sccm gas, 30 sccm of CH ₄ gas, PH ₃
/ H ₂ gas at 1 sccm, B ₂ H ₆ / H ₂ gas at 10 sccc
m into the deposition chamber 1201. The opening of the conductance valve 407 was adjusted so that the pressure in the deposition chamber 1201 was 5 mTorr.

Next, the power of the RF power supply 403 is set to 0.40 W
/ Cm ³ and applied to the bias bar 1214. Thereafter, the power of a μW power supply (not shown) was set to 0.20 W / cm ² , μW power was introduced into the deposition chamber 1201 to generate glow discharge, a shutter was opened, and the i-type layer was placed on the n-type layer. The production was started, and the flow rates of the SiH ₄ gas and CH ₄ gas were changed in accordance with the flow rate change pattern shown in FIG. 13A. When an i-type layer having a thickness of 320 nm was produced, the shutter was closed and the μW power supply was turned off. The glow discharge was stopped, the RF power source 1203 was turned off, and the fabrication of the i-type layer was completed. Deposition chamber 12
01, SiH ₄ gas, CH ₄ gas, PH ₃ / H ₂ gas,
Stop the flow of the B ₂ H ₆ / H ₂ gas, and leave the deposition chamber 401 for 5 minutes.
After the H ₂ gas was kept flowing into the inside, the valve 2003 was surrounded, and the inside of the deposition chamber 1201 and the inside of the gas pipe were evacuated.

To form a p-type layer, the heater 1205 is set so that the temperature of the substrate 1204 becomes 250 ° C., 300 sccm of H ₂ gas flows into the deposition chamber 1201, and the conductance becomes so that the pressure becomes 10 mTorr. The opening of the valve was adjusted. When the substrate was sufficiently heated, SiH ₄ gas was 8 sccm and CH ₄ gas was 5 scc.
m, H ₂ gas 500 sccm, a B ₂ H ₆ / H ₂ gas 50
0 sccm was caused to flow into the deposition chamber 1201. Deposition chamber 1
The opening of the conductance valve 1207 was adjusted so that the pressure inside 201 became 20 mTorr.

Next, a μW power supply (not shown) was turned on at 0.40 W / c.
m ³ , μW power was introduced into the deposition chamber to generate glow discharge, the shutter 1215 was opened, and the formation of a p-type layer on the i-type layer was started. When the p-type layer having a thickness of 10 nm was formed, the shutter was closed, the μW power was turned off, glow discharge was stopped, and the formation of the p-type layer was completed.

SiH ₄ gas and CH ₄ in the deposition chamber 1201
Gas, B ₂ H ₆ / H ₂ stop the flow of gas, after continued to flow for 5 minutes, the deposition chamber 1201 F H ₂ gas, the valve 200
3 was closed, the inside of the deposition chamber 1201 and the inside of the gas pipe were evacuated, all valves were closed, and the leak valves 1209 were opened to leak the deposition chamber 1201.

Next, as in Example 1, a transparent electrode of ITO (In ₂ O ₃ + SnO) having a thickness of 80 nm was formed on the p-type layer.
₂ ) and chromium (Cr) having a layer thickness of 10 μm as a collecting electrode was deposited by a usual vacuum deposition method. Thus, the fabrication of the non-single-crystal silicon carbide solar cell was completed. This solar cell is referred to as (SC Ex. 11). Table 7 shows conditions for forming the n-type layer, the i-type layer, and the p-type layer.

<Comparative Example 11-1> When forming the i-type layer, SiH ₄ was formed according to the flow rate change pattern shown in FIG.
Except that the gas flow rate and the CH ₄ gas flow rate were changed, the solar cell of FIG. 1 was manufactured under the same conditions and under the same procedure as in Example 11. This solar cell will be called (SC Comp. 11-1).

<Comparative Example 11-2> When forming the i-type layer,
The solar cell of FIG. 1 was produced in the same manner and in the same procedure as in Example 11 except that no PH ₃ / H ₂ gas was flowed. This solar cell is referred to as (SC ratio 11-2).

<Comparative Example 11-3> When forming the i-type layer,
The solar cell of FIG. 1 was produced in the same manner and in the same procedure as in Example 11 except that the B ₂ H ₆ / H ₂ gas was not supplied. This solar cell is referred to as (SC Comp. 11-3).

<Comparative Example 11-4> Except that no PH ₃ / H ₂ gas or B ₂ H ₆ / H ₂ gas was allowed to flow when forming the i-type layer, the same conditions and the same procedure as in Example 11 were used. The solar cell of FIG. 1 was manufactured. This solar cell will be referred to as (SC Comp. 11-4).

<Comparative Example 11-5> In forming the i-type layer,
The solar cell of FIG. 1 was manufactured in the same manner and in the same procedure as in Example 11 except that the μW power was changed to 0.5 W / cm ³ .
This solar cell is referred to as (SC ratio 11-5).

<Comparative Example 11-6> When forming the i-type layer,
Example 11 except that the RF power was set to 0.15 W / cm ³
The solar cell of FIG. 1 was produced by the same method and the same procedure as in the above. This solar cell is referred to as (SC ratio 11-6).

<Comparative Example 11-7> In forming the i-type layer,
μW power of 0.5 W / cm ³ , RF power of 0.55 W /
The solar cell of FIG. 1 was produced in the same manner and in the same procedure as in Example 11 except that the thickness was set to cm ³ . This solar cell (SC
Ratio 11-7).

<Comparative Example 11-8> In forming the i-type layer,
Example 11 except that the pressure in the deposition chamber was set to 80 mTorr.
The solar cell of FIG. 1 was produced by the same method and the same procedure as in the above. This solar cell is referred to as (SC ratio 11-8).

When the initial photoelectric conversion efficiency and the durability characteristics of these manufactured solar cells were measured by the same method as in Example 1, (SC Ex. 11) of the present invention showed that the conventional solar cell (SC
It was found to have better initial photoelectric conversion efficiency and durability than the ratios 11-1) to (SC ratio 11-8).

Further, when the change of the band gap in the layer thickness direction was examined in the same manner as in Example 1, the solar cells (SC actual 11), (SC ratio 11-2) to (SC ratio 11-
8), it was found that the minimum value of the band gap of the i-type layer was closer to the p / i interface than the center of the i-type layer, as shown in (SC Ex. 1) of FIG. Solar cells (SC ratio 11-1)
In FIG. 8, it was found that it was located closer to the n / i interface as in (SC ratio 1-1) in FIG.

<Comparative Example 11-9> Microwave (μW) power and RF power introduced when forming the i-type layer in Example 11 were variously changed, and other conditions were the same as in Example 11. Several non-single-crystal silicon carbide solar cells were fabricated.

FIG. 18 shows the relationship between the μW power and the deposition rate. The deposition rate does not depend on the RF power, and the μW power is 0.32 W /
cm ³ or more, and this electric power
H ₄ gas and CH ₄ gas was found to be degraded 100%.

The initial photoelectric conversion efficiency of the solar cell when irradiated with AM1.5 (100 mW / cm ² ) light was measured. The result is shown in FIG. The curve in FIG. 19 is an envelope for indicating the ratio of the initial photoelectric conversion efficiency of each solar cell when the initial photoelectric conversion efficiency of Example 11 is set to 1.
As can be seen from Figure, .mu.W power SiH ₄ gas and C
ΜW power for decomposing 100% of H ₄ gas (0.32W / c
m ³ ) or less and the RF power was larger than the μW power, it was found that the initial photoelectric conversion efficiency was greatly improved.

<Comparative Example 11-10> When forming the i-type layer in Example 11, the flow rate of the gas introduced into the deposition chamber was changed to SiH _4.
The gas was changed to 50 sccm, the CH ₄ gas was changed to 10 sccm, the H ₂ gas was not introduced, and the μW power and the RF power were variously changed to produce some non-single-crystal silicon carbide solar cells. Other conditions were the same as in Example 11. Deposition rate and μ
When the relationship between W power and RF power was examined, Comparative Example 11-
As in the case of No. 9, 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.
100% of SiH ₄ gas and CH ₄ gas as source gas
It was found to be decomposed.

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

<Comparative Example 11-11> In forming the i-type layer in Example 11, the flow rate of the gas introduced into the deposition chamber was changed to SiH _4.
The gas power was changed to 200 sccm for gas, 50 sccm for CH ₄ gas, and 500 sccm for H ₂ gas.
Several non-single-crystal silicon carbide solar cells were fabricated with various F powers. Other conditions were the same as in Example 11. When the relationship between the deposition rate, the μW power, and the RF power was examined, the deposition rate did not depend on the RF power and the μW power was constant at 0.65 W / cm ³ or higher as in Comparative Example 1-9. It was found that 100% of the SiH ₄ gas and the CH ₄ gas as the raw material gas were decomposed by the electric power.

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
ΜW power for decomposing gas by 100% (0.65 W / c
m ³ ) or less and the RF power was larger than the μW power, it was found that the initial photoelectric conversion efficiency was greatly improved.

<Comparative Example 11-12> In forming the i-type layer in Example 11, the pressure in the deposition chamber was increased from 3 mTorr to 20 m / s.
Various conditions were changed up to 0 mTorr, and other conditions were the same as in Example 11.
Several non-single-crystal silicon carbide solar cells were fabricated in the same manner as in Example 1. When the initial photoelectric conversion efficiency of the solar cell when irradiating AM1.5 light was measured, it was found that the initial photoelectric conversion efficiency was significantly reduced when the pressure was 50 mTorr or more, as shown in FIG.

As described above, Comparative Examples 11-1 to 11
−12>, the solar cell of the present invention (SC Ex. 1)
1) is (SC ratio 11-1) to (S
It has been found that the composition has even better initial photoelectric conversion efficiency and durability than the C ratio of 11-8), and the effects of the present invention can be obtained at a pressure of 50 mTorr or less without depending on manufacturing conditions such as a raw material gas flow rate and a substrate temperature. It has been demonstrated that it is demonstrated.

Embodiment 12 When forming a semiconductor layer of the non-single-crystal silicon carbide solar cell of FIG. 1 by a deposition apparatus using a microwave plasma CVD method shown in FIG. 12, 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 or less from the deposition chamber to produce a non-single-crystal silicon carbide solar cell (SC Ex. 12) in the same manner and in the same procedure as in Example 11. . The manufactured solar cell (SC Ex 12) is (SC Ex 11)
It was found to have even better initial photoelectric conversion efficiency and durability characteristics.

Example 13 A tandem solar cell having a non-single-crystal silicon carbide semiconductor layer and having a non-single-crystal silicon carbide semiconductor layer as shown in FIG. 14 was manufactured using the deposition apparatus of FIG. 12 using the microwave plasma CVD method of the present invention.

First, a base was produced. As in Example 1, a 50 × 50 mm ² stainless steel substrate was subjected to ultrasonic cleaning with acetone and isopropanol and dried. 0.3 μm on the surface of the stainless steel substrate by sputtering
Ag (silver) reflective layer was formed. At this time, the substrate temperature was set to 350 ° C., and the surface of the substrate was made uneven (texture).
I made it. On top of that, a substrate temperature of 350 ° C. and 1.0 μm of Zn
An O (zinc oxide) reflection increasing layer was formed.

Next, the deposition apparatus of FIG. 4 and the source gas supply apparatus were disconnected at the auxiliary valve, and the deposition apparatus of FIG. 12 and the source supply apparatus of FIG. 4 were connected.
Preparation for film formation was completed by the same method.

A first n-type layer was formed on a substrate by the same procedure and in the same manner as in Example 11, and a first i-type layer, a first p-type layer, a second n-type layer, A second i-type layer and a second p-type layer were sequentially formed. When forming the second i-type layer, FIG.
SiH ₄ gas flow rate according to flow rate change pattern such as -1, was varied CH ₄ gas flow rate.

Next, in the same manner as in Example 1, an 80 nm-thick ITO (In ₂ O ₃ +
SnO ₂ ) and chromium (Cr) having a layer thickness of 10 μm as a current collecting electrode were deposited by an ordinary vacuum deposition method.

Thus, the manufacture of the tandem solar cell using the microwave plasma CVD method has been completed. This solar cell is referred to as (SC Ex. 13), and Table 8 shows the manufacturing conditions of each semiconductor layer.

<Comparative Example 13-1> The embodiment was performed except that the flow rate of the SiH ₄ gas and the flow rate of the CH ₄ gas were changed in accordance with the flow rate change pattern of FIG. 13-2 when forming the second i-type layer of FIG. A tandem solar cell was manufactured in the same manner and by the same procedure as in Example 13. This solar cell (SC ratio 13-1)
I will call it.

<Comparative Example 13-2> A tandem solar cell was manufactured in the same manner as in Example 13 except that no PH ₃ / H ₂ gas was supplied when forming the second i-type layer in FIG. A battery was manufactured. This solar cell is referred to as (SC ratio 13-2).

<Comparative Example 13-3> In forming the second i-type layer in FIG. 14, a tandem method was performed in the same manner as in Example 13 except that B ₂ H ₆ / H ₂ gas was not supplied. A solar cell was fabricated. This solar cell is referred to as (SC ratio 13-3).

<Comparative Example 13-4> In forming the second i-type layer in FIG. 14, the same procedure as in Example 13 was carried out except that no PH ₃ / H ₂ gas or B ₂ H ₆ / H ₂ gas was passed. A tandem solar cell was manufactured by the same method and procedure. This solar cell (SC
The ratio will be referred to as 13-4).

<Comparative Example 13-5> In forming the second i-type layer in FIG. 14, a tandem method was performed in the same manner as in Example 13, except that the μW power was changed to 0.5 W / cm ^3. A solar cell was fabricated. This solar cell (SC ratio 13-5)
I will call it.

<Comparative Example 13-6> In forming the second i-type layer of FIG. 14, a tandem method was performed in the same manner as in Example 13, except that the RF power was set to 0.15 W / cm ^3. A solar cell was fabricated. This solar cell (SC ratio 13-
6).

<Comparative Example 13-7> When forming the second i-type layer of FIG. 14, a μW power higher than the microwave energy required to decompose 100% of the SiH ₄ gas was applied by 0.5 W.
Tandem-type solar cell was produced in the same manner and in the same procedure as in Example 13 except that the RF power was set to 0.55 W / cm ³ and the RF power was set to 0.55 W / cm ³ . This solar cell is referred to as (SC ratio 13-7).

<Comparative Example 13-8> A tandem solar cell was manufactured in the same manner as in Example 13, except that the pressure in the deposition chamber was set to 80 mTorr when forming the second i-type layer in FIG. Was prepared. This solar cell (SC ratio 13-
8).

The initial photoelectric conversion efficiency and durability of these tandem solar cells were measured in the same manner as in Example 1. The result (SC Ex. 13) was that of a conventional tandem solar cell (SC ratio 13-1). ) To (SC ratio 13-8) were found to have better initial photoelectric conversion efficiency and durability.

Example 14 The triple solar cell of FIG. 15 having a non-single-crystal silicon carbide semiconductor layer was manufactured using the manufacturing apparatus of FIG. 12 using the microwave plasma CVD method of the present invention.

First, a base was produced. A 50 × 50 mm ² stainless steel substrate was subjected to ultrasonic cleaning with acetone and isopropanol and dried in the same manner as in Example 1. Using a sputtering method, a substrate temperature of 3
A reflective layer of 0.3 μm Ag (silver) was formed at 50 ° C., and the substrate surface was made uneven (textured). A reflection enhancement layer of ZnO (zinc oxide) having a thickness of 1.0 μm was formed thereon at a substrate temperature of 350 ° C.

[0246] First, disconnect the deposition apparatus and the raw material gas supply apparatus of Figure 4 at the auxiliary valve, used to connect the material supply device of the deposition device and 4 in FIG. 12, further NH ₃ / H ₂
GeH ₄ gas (purity 99.999) instead of gas cylinder
%) A cylinder was connected, and preparation for film formation was completed by the same procedure and method as in Example 1.

A first n-type layer was formed on a substrate by the same procedure and in the same manner as in Example 11, and 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, a third i-type layer, and a third p-type layer were sequentially formed.

When forming the third i-type layer, the flow rate of SiH ₄ gas and C
The H ₄ gas flow rate was changed.

Next, as in Example 1, an 80 nm-thick ITO (In ₂ O ₃ +) layer was formed on the third p-type layer as a transparent electrode.
SnO ₂ ) and chromium (Cr) having a layer thickness of 10 μm as a current collecting electrode were deposited by an ordinary vacuum deposition method.

Thus, the fabrication of the triple solar cell using the microwave plasma CVD method is completed. This solar cell is referred to as (SC Ex. 14), and Table 9 shows the manufacturing conditions of each semiconductor layer.

<Comparative Example 14-1> The embodiment was performed except that the flow rate of the SiH ₄ gas and the flow rate of the CH ₄ gas were changed in accordance with the flow rate change pattern of FIG. 13-2 when forming the third i-type layer of FIG. A triple solar cell was manufactured in the same manner as in No. 14, and in the same procedure. This solar cell (SC ratio 14-1)
I will call it.

<Comparative Example 14-2> When forming the third i-type layer in FIG. 15, except that no PH ₃ / H ₂ gas was supplied, the triple solar cell was manufactured in the same manner and in the same procedure as in Example 14. A battery was manufactured. This solar cell is referred to as (SC ratio 14-2).

<Comparative Example 14-3> When forming the third i-type layer of FIG. 15, except that the B ₂ H ₆ / H ₂ gas was not flowed, a triple method was performed by the same method and the same procedure as in Example 14. A solar cell was fabricated. This solar cell will be referred to as (SC Comp. 14-3).

<Comparative Example 14-4> In forming the second i-type layer in FIG. 15, the same procedure as in Example 14 was carried out except that no PH ₃ / H ₂ gas or B ₂ H ₆ / H ₂ gas was passed. A tandem solar cell was manufactured by the same method and procedure. This solar cell (SC
Ratio 14-4).

<Comparative Example 14-5> When forming the third i-type layer in FIG. 15, a triple method was performed in the same manner and in the same procedure as in Example 14 except that the μW power was changed to 0.5 W / cm ^3. A solar cell was fabricated. This solar cell (SC ratio 14-5)
I will call it.

<Comparative Example 14-6> When forming the third i-type layer in FIG. 15, except that the RF power was set to 0.15 W / cm ³ , a triple method was performed by the same method and the same procedure as in Example 14. A solar cell was fabricated. This solar cell (SC ratio 14-
6).

[0257] <Comparative Example 14-7> forming the third i-type layer in FIG. 15, except that the μW power 0.5 W / cm ^3, the RF power to 0.55 W / cm ³ Example 14 A triple-type solar cell was produced in the same manner and in the same procedure. This solar cell is referred to as (SC ratio 14-7).

<Comparative Example 14-8> A triple-type solar cell was manufactured in the same manner as in Example 14 except that the pressure in the deposition chamber was changed to 80 mTorr when forming the third i-type layer in FIG. Was prepared. This solar cell (SC ratio 14-
8).

The initial photoelectric conversion efficiency and durability characteristics of these fabricated triple solar cells were measured in the same manner as in Example 1. The result (SC Ex. 14) was that of a conventional triple solar cell (SC ratio 14-1). ) To (SC ratio 14-8) were found to have better initial photoelectric conversion efficiency and durability.

Example 15 Using the manufacturing apparatus of FIG. 12 using the microwave plasma CVD method of the present invention, FIG.
Five triple solar cells were fabricated, modularized, and applied to a power generation system.

A triple solar cell of 50 × 50 mm ² (SC Ex. 1) was produced under the same conditions, under the same method, and under the same procedure as in Example 14.
4) were prepared in 65 pieces. An adhesive sheet made of EVA (ethylene vinyl acetate) is placed on an aluminum plate having a thickness of 5.0 mm, a nylon sheet is placed on the adhesive sheet, and the solar cells produced are further arranged on the adhesive sheet, and serialization and parallelization are performed. went. An EVA adhesive sheet was placed thereon, and a fluororesin sheet was further placed thereon, followed by vacuum lamination to form a module.

The initial photoelectric conversion efficiency of the manufactured module was measured in the same manner as in Example 1. The circuit was connected to the circuit showing the power generation system shown in FIG. The entire system was powered by the battery and the module's power, and the module was installed at an angle that could collect sunlight most. Measure the photoelectric conversion efficiency after one year,
Light degradation rate (photoelectric conversion efficiency after one year / initial photoelectric conversion efficiency)
I asked. This module is called (MJ Actual 15).

<Comparative Example 15-1> A conventional triple solar cell (SC ratio: 14-X) (X: 1 to 8) was used in Comparative Example 14-
65 pieces were manufactured under the same conditions, the same method, and the same procedure as those of X, and were 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 had elapsed were measured under the same conditions, the same method, and the same procedure as in Example 15, and the light deterioration rate was obtained. As a result, (MJ ratio 15-
The light degradation rate of (X) was as follows with respect to (MJ Actual 15).

[0265] From the above results, it was found that the solar cell module of the present invention had more excellent light degradation characteristics than the conventional solar cell module.

Example 16 A non-single-crystal silicon carbide solar cell in which the hydrogen content of the i-type layer was changed corresponding to the silicon content was manufactured. O ₂ / He gas cylinder is SiF ₄
When the gas (purity: 99.999%) is exchanged for a cylinder and an i-type layer is formed, Si gas is formed according to the flow rate pattern shown in FIG.
The flow rates of H ₄ gas, CH ₄ gas, and SiF ₄ gas were changed. In the same manner as in Example 1, this solar cell (S
When the change of the band gap in the layer thickness direction of C Ex 17) was obtained, the same result as that of FIG. 17-2 was obtained.

Further, the content of hydrogen atoms and silicon atoms was analyzed in the layer thickness direction using SIMS. As a result, as shown in FIG. 17C, it was found that the hydrogen atom content had a distribution in the layer thickness direction corresponding to the silicon atom content.

When the initial photoelectric conversion efficiency and durability characteristics of this solar cell (SC Ex 16) were determined, similar to the solar cell of Example 1, conventional solar cells (SC ratio 1-1) to (SC ratio 1) were obtained.
4) It was found to have better initial photoelectric conversion efficiency and durability characteristics than those of (4).

Example 17 In this example, the solar cell of FIG. 1 having a p-type layer laminated structure was manufactured.

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

Next, the source gas supply device 200 shown in FIG.
A semiconductor layer was formed on the reflection-enhancing layer by a manufacturing apparatus using a glow discharge decomposition method including the deposition apparatus 1200 shown in FIG.

After preparation for film formation was completed in the same manner as in Example 1, n-type, i-type, and p-type semiconductor layers were formed on the substrate 1204. The SiH ₄ gas and CH ₄ gas were mixed at a distance of m from the deposition chamber.

To form an n-type layer, the auxiliary valve 120
8. The valve 2003 is gradually opened, H ₂ gas is introduced into the deposition chamber 1201 through the gas introduction pipe, and the mass flow controller 2013 is set so that the H ₂ gas flow rate becomes 50 sccm. The conductance valve was adjusted so that the pressure became 0 Torr while watching the vacuum gauge 1202, and the heater 1205 was set so that the temperature of the substrate 1204 became 350 ° C. When the substrate was sufficiently heated, the valves 2001 and 2004 were gradually opened, and SiH ₄ gas and PH ₃ / H ₂ gas were supplied to the deposition chamber 1.
It flowed into 201. At this time, the flow rate of the SiH ₄ gas is 2
sccm, H ₂ gas flow rate is 100 sccm, PH ₃ / H ₂
Each mass flow controller 2011, 2013, 2014 adjusted the gas flow rate to 20 sccm. The conductance valve 1207 is monitored while watching the vacuum gauge 1202 so that the pressure in the deposition chamber becomes 1.0 Torr.
The opening of was adjusted. After confirming that the shutter 1215 was closed, the power of the RF power source was set to 7 mW / cm ³ , and RF power was introduced into the bias rod 1214 to generate glow discharge. The shutter is opened to start forming an n-type layer on the substrate 1204. When the n-type layer having a thickness of 20 nm is formed, the shutter is closed, the RF power is turned off, glow discharge is stopped, and the formation of the n-type layer is completed. Was. Valve 200
1, 2004 is closed and SiH ₄ in the deposition chamber 1201 is closed.
Stop inflow of gas and PH ₃ / H ₂ gas, deposition chamber 1 for 5 minutes
After continuing to flow H ₂ gas into 201, the outflow valve 20
03 was closed, and the inside of the deposition chamber 1201 and the inside of the gas pipe were evacuated.

Next, in order to manufacture an i-type layer, the valve 20 was used.
03 was gradually opened, H ₂ gas was introduced into the deposition chamber 1201, and the mass flow controller 2013 adjusted the flow rate of H ₂ gas to 300 sccm. Adjusting the conductance valve while watching the vacuum gauge 1202 so that the pressure in the deposition chamber becomes 0.01 Torr.
The heater 1205 is set so that the temperature of the substrate becomes 350 ° C.
001 and 2002 are gradually opened, and SiH ₄ gas, CH ₄
Gas was flowed into the deposition chamber 1201. At this time, SiH
₄ gas flow rate 100sccm, CH ₄ gas flow rate 30scc
m and H ₂ gas flow rate were adjusted to 300 sccm by each mass flow controller. Deposition chamber 120
The pressure inside the vacuum gauge 1 is set to 0.01 Torr.
While watching 202, the opening of the conductance valve 1207 was adjusted.

Next, the power of the RF power supply 1203 is reduced to 0.40
W / cm ³ was set and applied to the bias bar 1214.
Thereafter, the electric power of a μW power supply (not shown) was increased to 0.20 W / cm ^2.
, And a μW power was introduced into the deposition chamber 1201 through the dielectric window 1213 to generate glow discharge, the shutter was opened, and the formation of the i-type layer on the n-type layer was started. Using a computer connected to the mass flow controller, the Si flow was changed in accordance with the flow rate change pattern shown in FIG.
The flow rate of H ₄ gas and CH ₄ gas was changed, and the layer thickness was 300 nm.
When the i-type layer was formed, the shutter was closed and the μW
The power supply was turned off to stop glow discharge, the RF power supply 1203 was turned off, and the fabrication of the i-type layer was completed. Valve 2001, 2002
Is closed, the flow of the SiH ₄ gas and the CH ₄ gas into the deposition chamber 1201 is stopped, and the H ₂ gas is continuously flown into the deposition chamber 1201 for 5 minutes.
The inside of 01 and the inside of the gas pipe were evacuated.

To form a p-type layer, the valve 2003 was gradually opened, and H ₂ gas was introduced into the deposition chamber 1201.
The mass flow controller 2013 adjusted the H ₂ gas flow rate to 300 sccm. The conductance valve is adjusted while watching the vacuum gauge 1202 so that the pressure in the deposition chamber becomes 0.02 Torr, and the heater 1205 is set so that the temperature of the substrate 1204 becomes 200 ° C. When the substrate is sufficiently heated, the temperature is further increased. Valve 200
1, 2002 and 2005 are gradually opened, and SiH ₄ gas, CH ₄ gas, H ₂ gas and B ₂ H ₆ / H ₂ gas are deposited in the deposition chamber 1
It flowed into 201. At this time, the SiH ₄ gas flow rate is 1
0 sccm, CH ₄ gas flow rate 5 sccm, H ₂ gas flow rate 300 sccm, B ₂ H ₆ / H ₂ gas flow rate 10 sccc
m was adjusted by each mass flow controller. The opening of the conductance valve 1207 was adjusted while watching the vacuum gauge 1202 so that the pressure in the deposition chamber 1201 became 0.02 Torr.

The μW power supply was set to 0.30 W / cm ³ ,
ΜW power is introduced into the deposition chamber 1201 through the dielectric window 1213 to generate glow discharge, and the shutter 1215
Was opened to start forming a lightly doped layer (this layer is referred to as a B layer) on the i-type layer. When the B layer having a thickness of 3 nm was formed, the shutter was closed, the μW power was turned off, and the glow discharge was stopped. The valves 2001, 2002, and 2005 are closed, and the SiH ₄ gas, CH ₄ gas, B
Stop the flow of ₂ H ₆ / H ₂ gas, and deposit for 5 minutes in deposition chamber 1201
After the H ₂ gas was kept flowing into the inside, the valve 2003 was closed, and the inside of the deposition chamber 1201 and the inside of the gas pipe were evacuated.

Next, the valve 2005 is gradually opened, and B ₂ H ₆ / H ₂ gas is introduced into the deposition chamber 1201 so that the flow rate becomes 1
It was adjusted with a mass flow controller so as to be 000 sccm. While adjusting the conductance valve while watching the vacuum gauge 1202 so that the pressure in the deposition chamber becomes 0.02 Torr, the power of the μW power supply is set to 0.20 W / cm ² , and μW power is introduced into the deposition chamber 1201. Glow discharge was generated, the shutter 1215 was opened, and the formation of a layer of boron (B) on the layer B (this layer is referred to as layer A) was started. After 6 seconds, the shutter was closed, the μW power was turned off, and glow discharge was stopped. The valve 2005 is closed, the introduction of the B ₂ H ₆ / H ₂ gas into the deposition chamber 1201 is stopped, and the H ₂ gas is continuously flowed into the deposition chamber 1201 for 5 minutes. And the inside of the gas pipe was evacuated.

Subsequently, the B layer, the A layer, and the B layer were sequentially formed on the A layer by the same method, the same procedure, and the same conditions as those described above, and the formation of a p-type layer having a thickness of about 10 nm was completed.

The auxiliary valve 1208 was closed, the leak valve 1209 was opened, and the deposition chamber 1201 was leaked.

Next, on the p-type layer, ITO (In ₂ O ₃ + SnO ₂ ) having a layer thickness of 80 nm as a transparent electrode and chromium (Cr) having a layer thickness of 10 μm as a collecting electrode were formed by a normal vacuum deposition method. Evaporated. Thus, the fabrication of the non-single-crystal silicon carbide solar cell was completed. This solar cell is referred to as (SC Ex. 17). Table 10 shows the conditions for forming the n-type layer, the i-type layer, and the p-type layer.

<Comparative Example 17-1> When forming the i-type layer, the flow rate of the SiH ₄ gas and the flow rate of the CH ₄ gas were changed as shown in FIG.
Except for adjusting by each mass flow controller according to the flow rate pattern shown in the above, on the base under the same conditions and the same procedure as in Example 17, a reflective layer, a reflection increasing layer, an n-type layer, an i-type layer, a p-type layer, a transparent An electrode and a current collecting electrode were formed to produce a solar cell. This solar cell is referred to as (SC ratio 17-1).

<Comparative Example 17-2> A reflective layer was formed on a substrate under the same conditions and in the same procedure as in Example 17 except that the μW power was changed to 0.5 W / cm ³ when forming the i-type layer. , A reflection increasing layer, an n-type layer, an i-type layer, a p-type layer, a transparent electrode, and a current collecting electrode were formed to produce a solar cell. This solar cell (SC
Ratio 17-2).

<Comparative Example 17-3> A reflective layer was formed on a substrate under the same conditions and in the same procedure as in Example 17 except that the RF power was changed to 0.15 W / cm ³ when forming the i-type layer. , A reflection increasing layer, an n-type layer, an i-type layer, a p-type layer, a transparent electrode, and a current collecting electrode were formed to produce a solar cell. This solar cell is (S
C ratio 17-3).

<Comparative Example 17-4> In forming an i-type layer, μW power was 0.5 W / cm ³ and RF power was 0.55.
A reflecting layer, a reflection increasing layer, an n-type layer, an i-type layer, a p-type layer, a transparent electrode, and a collecting electrode were formed on a substrate under the same conditions and in the same procedure as in Example 17 except that the W / cm ³ was used. The solar cell was formed by forming. This solar cell is referred to as (SC ratio 17-4).

<Comparative Example 17-5> When forming the i-type layer, except that the pressure in the deposition chamber was set to 0.08 Torr,
Under the same conditions and in the same procedure as in Example 17, a reflective layer, a reflection enhancement layer, an n-type layer, an i-type layer, a p-type layer, a transparent electrode,
A current collecting electrode was formed to produce a solar cell. This solar cell is referred to as (SC ratio 17-5).

Measurement of the initial photoelectric conversion efficiency (photovoltaic power / incident light power) and durability characteristics of the solar cells (SC Ex. 17) and (SC Comp. 17-1) to (SC Comp. Done.

As a result of the measurement, the initial photoelectric conversion efficiency of (SC ratio 17-1) to (SC ratio 17-5) for the solar cell of (SC Ex. 17) was as follows.

(SC ratio 17-1) 0.86 times (SC ratio 17-2) 0.63 times (SC ratio 17-3) 0.80 times (SC ratio 17-4) 0.65 times (SC ratio) 17-5) 0.72 times On the other hand, the durability of the solar cell (SC Ex. 17) of the present example is (SC ratio 17) compared to the solar cell of (SC Ex. 17).
-1) to (SC ratio 17-5), the decrease in photoelectric conversion efficiency was as follows.

(SC ratio 17-1) 0.85 times (SC ratio 17-2) 0.78 times (SC ratio 17-3) 0.79 times (SC ratio 17-4) 0.76 times (SC ratio) 17-5) 0.70 times Further, i of solar cells (SC Ex. 17), (SC ratio 17-1) to (SC ratio 17-5) manufactured in the same manner as in Example 1
When the change of the band gap in the layer thickness direction in the mold layer was determined, (SC actual 17), (SC ratio 17-2) to (SC
In the solar cell of the ratio 17-5), the position of the minimum value of the band gap is shifted from the center position of the i-type layer toward the p / i interface, and in the solar cell of the ratio (SC ratio 17-1), the band gap is Is n / n from the center of the i-type layer.
It was confirmed that it was offset in the direction of the i interface.

Next, a p-type layer was formed on the silicon substrate (111), and its cross-sectional TEM (transmission electron microscope) image was observed. A p-type layer was formed on a silicon substrate by the same method and procedure as in Example 17 except that the deposition time of the A layer was changed to 12 seconds. The prepared 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. As shown in FIG. 21, the A layer having a thickness of about 1 nm and the B layer having a thickness of about 3 nm were formed. It was found that the layers were alternately stacked.

<Comparative Example 17-6> A non-single-crystal silicon carbide solar cell was manufactured in the same manner as in Example 17 except that the μW power and the RF power introduced when forming the i-type layer were variously changed. Several were made.

The relationship between the μW power and the deposition rate is similar to that shown in FIG. 18, and the deposition rate does not depend on the RF power.
W power is constant at 0.32 W / cm ³ or more, SiH ₄ gas and CH ₄ gas as a source gas in this power 100
% Decomposition was found.

AM1.5 (100 mW / cm ² )
When the initial photoelectric conversion efficiency of the solar cell when irradiated with light was measured, the result was similar to that in FIG.
It was found that the initial photoelectric conversion efficiency was significantly improved when the power was not more than μW power (0.32 W / cm ³ ) for decomposing the iH ₄ gas and CH ₄ gas by 100% and the RF power was larger than the μW power.

[0295] In the formation of the i-type layer in <Comparative Example 17-7> Example 17, to change the flow rate of the gas introduced into the deposition chamber SiH ₄ gas 50 sccm, a CH ₄ gas 10 sccm, H ₂
No gas was introduced, and several non-single-crystal silicon carbide solar cells were fabricated with various μW power and RF power. Other conditions were the same as in Example 17.

When the relationship between the deposition rate and the μW power and RF power was examined, the deposition rate did not depend on the RF power as in Comparative Example 17-6, and was constant when the μW power was 0.18 W / cm ³ or more. It was found that the SiH ₄ gas and the CH ₄ gas, which are the source gases, were decomposed 100% with this μW power.

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

<Comparative Example 17-8> When forming the i-type layer in Example 17, the flow rates of the gas introduced into the deposition chamber were 200 sccm for SiH ₄ gas, 50 sccm for CH ₄ gas, and 5 for H ₂ gas.
00 sccm, and the heater setting was changed so that the substrate temperature was 300 ° C.
Several non-single-crystal silicon carbide solar cells were fabricated with varying power. Other conditions were the same as in Example 17.
The relationship between the deposition rate, the μW power, and the RF power was examined. As in Comparative Example 17-6, the deposition rate was constant at 0.65 W / cm ³ or higher without depending on the RF power. It was found that SiH ₄ gas and CH ₄ gas, which were gases, were decomposed by 100%.

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
ΜW power for decomposing gas by 100% (0.65 W / c
m ³ ) or less and the RF power was larger than the μW power, it was found that the initial photoelectric conversion efficiency was greatly improved.

<Comparative Example 17-9> In forming the i-type layer in Example 17, the pressure in the deposition chamber was increased from 3 mTorr to 200.
Various non-single-crystal silicon carbide solar cells were manufactured under various conditions up to mTorr and the other conditions were the same as in Example 17. When the initial photoelectric conversion efficiency of the solar cell when irradiating AM1.5 light was measured, the pressure was 50 mTorr.
From the above, it was found that the initial photoelectric conversion efficiency was greatly reduced.

As described above, Comparative Examples 17-1 to 17
-9>, the solar cell of the present invention (SC Ex. 1)
7) was found to have more excellent characteristics than the conventional solar cells (SC ratio 17-1) to (SC ratio 17-5), and at a pressure of 50 mTorr or less, the raw material gas flow rate, substrate temperature It has been demonstrated that excellent characteristics can be obtained without depending on the manufacturing conditions.

Example 18 In Example 17, several solar cells were manufactured 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. The photoelectric conversion efficiency and the durability were examined in the same manner as in Example 17. At this time, the 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 17. In this example, the solar cell having the band diagram shown in FIG. 9 was manufactured by changing the change pattern of the SiH ₄ gas flow rate and the CH ₄ gas flow rate.

Table 11 shows the results obtained by examining the initial photoelectric conversion efficiency and durability characteristics of these manufactured solar cells. Here, each value was standardized based on the value of (SC Ex 18-1).

As can be seen from these results, the band gap of the i-type layer smoothly changes in the layer thickness direction regardless of the magnitude and the change pattern of the minimum value of the band gap, and the position of the minimum value of the band gap is changed. It has been found that the solar cell of the present invention, which is offset in the p / i interface direction from the center position of the i-type layer, is superior.

Example 19 A solar cell having the A layer formed by a mercury-sensitized photo-assisted CVD method was manufactured. The manufacturing apparatus shown in FIG.
A quartz glass window having a thickness of 100 mm and a thickness of 10 mm and a low-pressure mercury lamp were attached, and light from the low-pressure mercury lamp was allowed to enter the deposition chamber through the quartz glass window. In addition, a shutter (window shutter) for covering the quartz glass window was installed inside the deposition chamber so that the deposits did not adhere.
Further, containers with valves at the inlet and outlet (204 in FIG. 4)
8) was filled with mercury (purity 99.999%). Mounting the container between the valve 2005 and the mass flow controllers 2015, by bubbling with B ₂ H ₆ / H ₂ gas, and to be able to introduce the vaporized mercury with B ₂ H ₆ / H ₂ gas into the deposition chamber.

When the A layer is formed, the flow rate of the B ₂ H ₆ / H ₂ gas is set at 1000 sccm into the deposition chamber, the pressure is set to 1.0 Torr, the shutter 1215 is opened in advance, and the low-pressure mercury lamp is turned on. The window shutter was opened for 60 seconds to form the layer A on the layer B. Except for this, the solar cell of FIG. 1 was manufactured under the same conditions, the same method, and the same procedure as in Example 17.

The fabricated solar cell (SC Ex. 19) is (SC
As in the case of the actual solar cell 17), the conventional solar cell (SC ratio 17-1) ~
It was found to have better initial photoelectric conversion efficiency and durability than (SC ratio 17-5).

Example 20 A solar cell was fabricated in which the order of lamination of the n-type layer and the p-type layer was reversed. Table 12 shows the conditions for forming the p-type layer, the i-type layer, and the n-type layer. When forming an i-type layer,
The flow rates of the SiH ₄ gas and the CH ₄ gas were changed as shown in the pattern of FIG. 13-2 so that the minimum value of the band gap was located closer to the p / i interface. The n-type layer was formed into a laminated structure using the same method as in Example 17, and was formed using PH ₃ / H ₂ gas. The layers other than the semiconductor layer and the base were manufactured using the same conditions and the same method as in Example 17. The manufactured solar cell (SC Ex. 20) has better initial photoelectric conversion efficiency and durability than the conventional solar cells (SC Comp. 17-1) to (SC Comp. 17-5), similarly to (SC Ex. 17). It was found to have.

Example 21 A non-single-crystal silicon carbide solar cell having a region having the maximum value of the band gap of the i-type layer near the p / i interface and having a thickness of 20 nm was manufactured. The i-type layer was fabricated using the same conditions and the same method as in Example 17 except that the flow rate change pattern of the i-type layer was changed to the flow rate pattern shown in FIG. Next, composition analysis of the solar cell was performed in the same manner as in Example 17, and based on FIG.
When the change of the band gap in the thickness direction of the mold layer was examined, the result was as shown in FIG. 22-2.

The manufactured solar cell (SC Ex. 21) is (SC
As in the case of the actual solar cell 17), the conventional solar cell (SC ratio 17-1) ~
It was found to have better initial photoelectric conversion efficiency and durability than (SC ratio 17-5).

<Comparative Example 21> Some non-single-crystal silicon carbide solar cells were produced in which the maximum value of the band gap was present on the p / i interface side and the thickness of the region was variously changed.
Except for the thickness of the region, it was manufactured using the same conditions and the same method as in Example 21.

When the initial photoelectric conversion efficiency and durability characteristics of the manufactured solar cell were measured, when the thickness of the region was 1 nm or more and 30 nm or less, the solar cell of Example 17 (SC actual 1) was obtained.
Even better initial photoelectric conversion efficiency and durability were obtained than in 7).

Example 22 A non-single-crystal silicon carbide solar cell having a region having the maximum value of the band gap of the i-type layer near the n / i interface and having a thickness of 15 nm was manufactured. It was manufactured using the same conditions and the same method as in Example 17 except that the flow rate change pattern of the i-type layer was changed to the flow rate pattern of FIG. Next, the composition of the solar cell was analyzed in the same manner as in Example 17, and the change in the band gap in the thickness direction of the i-type layer was examined based on FIG.
The result was similar to -4.

The manufactured solar cell (SC Ex. 22) is (SC
As in the case of the actual solar cell 17), the conventional solar cell (SC ratio 17-1) ~
It was found to have better initial photoelectric conversion efficiency and durability than (SC ratio 17-5).

<Comparative Example 22> There was a region having the maximum value of the band gap near the n / i interface, and several non-single-crystal silicon carbide solar cells in which the thickness of the territory was changed variously were manufactured. Except for the thickness of the region, it was manufactured using the same conditions and the same method as in Example 22.

When the initial photoelectric conversion efficiency and durability characteristics of the manufactured solar cell were measured, when the thickness of the region was 1 nm or more and 30 nm or less, the solar cell of Example 17 (SC Ex. 1) was used.
Even better initial photoelectric conversion efficiency and durability were obtained than in 7).

Example 23 A solar cell using triethylboron (B (C ₂ H ₅ ) ₃ , hereinafter abbreviated as TEB) when forming a p-type layer was manufactured.

At room temperature and pressure, liquid TEB (purity 99.9)
9%) and a liquid cylinder with a valve at the inlet and outlet (Fig. 4
2048). The bomb was attached to the raw material gas supply device and bubbled with H ₂ gas, so that TEB vaporized together with H ₂ gas could be introduced into the deposition chamber.

When forming the B layer, the TEB / H ₂ gas was introduced into the deposition chamber in the same condition and procedure as in Example 17 except that TEB / H ₂ gas was introduced into the deposition chamber at 10 sccm instead of B ₂ H ₆ / H ₂ gas. After the layer B was formed and H ₂ gas was allowed to flow into the deposition chamber for 5 minutes, the deposition chamber was evacuated. When forming the A layer, instead of B ₂ H ₆ / H ₂ gas TEB / H ₂ Gas 10
Example 17 except that the flow was 00 sccm into the deposition chamber.
A layer is formed on the B layer under the same conditions and procedure as in
After flowing the _two gases into the deposition chamber, the deposition chamber was evacuated.

Further, similarly, on the A layer, the B layer, the A layer, and the B layer
After forming the layer, the deposition chamber was evacuated.

Except for the p-type layer, it was manufactured under the same conditions, method and procedure as in Example 17. The fabricated solar cell (SC actual 2)
3) was found to have better initial photoelectric conversion efficiency and durability than conventional solar cells (SC ratio 17-1) to (SC ratio 17-5), similarly to (SC Ex. 17).

Example 24 A non-single-crystal silicon carbide solar cell having an i-type layer containing oxygen atoms was manufactured. i
When forming the mold layer, in addition to the gas flowing in Example 17, O ₂
The same conditions, the same method, and the same procedure as in Example 17 were used, except that / He gas was introduced at 10 sccm into the deposition chamber.
The manufactured solar cells (SC Ex. 24) are the same as the conventional solar cells (SC Ex. 17-1) to (SC Ex.
It was found to have better initial photoelectric conversion efficiency and durability than -5). Further, when the content of oxygen atoms in the i-type layer was measured by SIMS, it was found that the content was almost uniform and 2 × 10 ¹⁹ (pieces / cm ³ ).

Example 25 A non-single-crystal silicon carbide solar cell in which a nitrogen atom was contained in an i-type layer was manufactured. i
When forming the mold layer, NH 4 was used in addition to the gas flowing in Example 17.
_The same conditions, the same method, and the same procedure as in Example 17 were used, except that ₃ / H ₂ gas was introduced into the deposition chamber at 5 sccm. The manufactured solar cell (SC Ex. 25) is similar to (SC Ex. 17).
Conventional solar cells (SC ratio 17-1) to (SC ratio 17-
It was found to have better initial photoelectric conversion efficiency and durability than 5).

The content of nitrogen atoms in the i-type layer is determined by SI
As a result of examination by MS, it was contained almost uniformly, and 3 × 10 ¹⁷
(Pieces / cm ³ ).

Example 26 A non-single-crystal silicon carbide solar cell having an i-type layer containing oxygen atoms and nitrogen atoms was manufactured. Example 17 In forming an i-type layer, Example 17 was repeated except that O ₂ / He gas was introduced at 5 sccm and NH ₃ / H ₂ gas was introduced at 5 sccm in addition to the gas flowing in Example 17.
The same conditions, method and procedure were used. Similar to (SC Ex. 17), the manufactured solar cell (SC Ex. 26) has better initial photoelectric conversion efficiency and durability than conventional solar cells (SC Comp. 17-1) to (SC Comp. 17-5). It was found to have. Further, when the contents of oxygen atoms and nitrogen atoms in the i-type layer were measured by SIMS, they were almost uniformly contained, each being 1 × 10 ¹⁹ (pieces / cm ³ ) and 3 × 10
¹⁷ (pieces / cm ³ ).

Example 27 A non-single-crystal silicon carbide solar cell in which the hydrogen content of the i-type layer was changed in accordance with the silicon content was manufactured. O ₂ / He gas cylinder is SiF ₄
When the gas (purity: 99.999%) was exchanged for a cylinder and an i-type layer was formed, Si was used in accordance with the flow pattern shown in FIG.
The flow rates of H ₄ gas, CH ₄ gas, and SiF ₄ gas were changed.

The change in band gap in the layer thickness direction of this solar cell (SC Ex. 27) was determined in the same manner as in Example 17, and the results shown in FIG. 23B were obtained.

Further, the content of hydrogen atoms and silicon atoms was analyzed in the layer thickness direction using SIMS. As a result, as shown in FIG. 23C, it was found that the hydrogen atom content had a distribution in the layer thickness direction corresponding to the silicon atom content.

When the initial photoelectric conversion efficiency and the durability characteristics of this solar cell (SC Ex. 27) were determined, similar to the solar cell of Example 17, conventional solar cells (SC ratio 17-1) to (SC ratio) were obtained.
Ratio 17-5) was found to have even better initial photoelectric conversion efficiency and durability.

Embodiment 28 When forming a semiconductor layer of the non-single-crystal silicon carbide solar cell of FIG. 1 by a manufacturing apparatus using a microwave plasma CVD method shown in FIG. 12, 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 or less from the deposition chamber, and a non-single-crystal silicon carbide solar cell (SC Ex. 28) was produced in the same manner and in the same procedure as in Example 17. . The manufactured solar cell (SC actual 28) is (SC actual 17)
It was found to have even better initial photoelectric conversion efficiency and durability characteristics.

Example 29 A tandem solar cell having a non-single-crystal silicon carbide semiconductor layer and having a non-single-crystal silicon carbide semiconductor layer as shown in FIG. 14 was manufactured using the manufacturing apparatus of FIG. 12 using the microwave plasma CVD method of the present invention.

First, a base was manufactured. A 50 × 50 mm ² stainless steel substrate was subjected to ultrasonic cleaning with acetone and isopropanol and dried as in Example 17. Using a sputtering method, 0.3μ
A reflective layer of Ag (silver) was formed. At this time, the substrate temperature was set at 350 ° C., and the substrate surface was made uneven (textured). A reflection enhancement layer of ZnO (zinc oxide) having a thickness of 1.0 μm was formed thereon at a substrate temperature of 350 ° C.

Next, a first n-type layer was formed on the substrate by the same procedure and in the same manner as in Example 17, and a first i-type layer, a first p-type layer, and a second n-type layer were formed. Mold layer, second i-type layer, second
Were sequentially formed. When forming the second i-type layer,
SiH accordance flow change pattern as shown in FIG. 13-1 ₄
The gas flow rate and the CH ₄ gas flow rate were changed, and the second p-type layer had a laminated structure as in Example 17.

Next, as in Example 17, an 80 nm-thick ITO (In ₂ O ₃₎ was formed on the second p-type layer as a transparent electrode.
+ SnO ₂ ) and chromium (Cr) having a layer thickness of 10 μm as a current collecting electrode were deposited by a normal vacuum deposition method.

Thus, the manufacture of the tandem solar cell using the microwave plasma CVD method has been completed. This solar cell is referred to as (SC Ex 29), and Table 13 shows the manufacturing conditions of each semiconductor layer.

<Comparative Example 29-1> The embodiment was performed except that the flow rate of the SiH ₄ gas and the flow rate of the CH ₄ gas were changed in accordance with the flow rate change pattern of FIG. 13-2 when forming the second i-type layer of FIG. A tandem solar cell was manufactured in the same manner and by the same procedure as in 29. This solar cell (SC ratio 29-1)
I will call it.

<Comparative Example 29-2> In forming the second i-type layer in FIG. 14, a tandem method was performed in the same manner as in Example 29, except that the μW power was changed to 0.5 W / cm ^3. A solar cell was fabricated. This solar cell (SC ratio 29-2)
I will call it.

<Comparative Example 29-3> In forming the second i-type layer of FIG. 14, a tandem method was performed in the same manner as in Example 29, except that the RF power was changed to 0.15 W / cm ^3. A solar cell was fabricated. This solar cell (SC ratio 29-
Let's call it 3).

[0339] <Comparative Example 29-4> when forming the second i-type layer in FIG. 14, except that the μW power 0.5 W / cm ^3, the RF power to 0.55 W / cm ³ Example 29 A tandem solar cell was manufactured in the same manner and in the same procedure as in the above. This solar cell is referred to as (SC Comp. 29-4).

<Comparative Example 29-5> When forming the second i-type layer in FIG. 14, a tandem type was formed by the same method and in the same procedure as in Example 29 except that the pressure in the deposition chamber was set to 0.1 Torr. A solar cell was manufactured. This solar cell (SC ratio 29-
Let's call it 5).

The initial photoelectric conversion efficiency and durability characteristics of these fabricated tandem solar cells were measured by the same method as in Example 17. The result (SC Ex. 29) was that of a conventional tandem solar cell (SC ratio 29-1). ) To (SC ratio 29-9) were found to have better initial photoelectric conversion efficiency and durability.

Example 30 The triple solar cell of FIG. 15 having a non-single-crystal silicon carbide semiconductor layer was manufactured using the manufacturing apparatus of FIG. 12 using the microwave plasma CVD method of the present invention.

First, a base was produced. A 50 × 50 mm ² stainless steel substrate was subjected to ultrasonic cleaning with acetone and isopropanol and dried as in Example 17. Using a sputtering method in the same manner as in Example 29, 0.3 μm Ag (silver) at a substrate temperature of 350 ° C. was formed on the surface of a stainless steel substrate.
To form a reflective layer and make the substrate surface uneven (texture)
I made it. On top of that, a substrate temperature of 350 ° C. and 1.0 μm of Zn
An O (zinc oxide) reflection increasing layer was formed.

First, G was used instead of the NH ₃ / H ₂ gas cylinder.
An eH ₄ gas (99.999% purity) cylinder was connected, and preparation for film formation was completed by the same method and procedure as in Example 17.

A first n-type layer was formed on a substrate by the same procedure and in the same manner as in Example 17, and 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, a third i-type layer, and a third p-type layer were sequentially formed.

When forming the third i-type layer, the flow rate of SiH ₄ gas and C
The H ₄ gas flow rate was changed. The second p-type layer and the third p-type layer had a laminated structure as in Example 17.

Next, as in Example 17, an 80 nm thick ITO (In ₂ O ₃₎ layer 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 current collecting electrode were deposited by a normal vacuum deposition method.

The fabrication of the triple type solar cell using the microwave plasma CVD method has been completed. This solar cell is referred to as (SC Ex 30), and Table 14 summarizes the manufacturing conditions of each semiconductor layer.

<Comparative Example 30-1> In forming the third i-type layer of FIG. 15, the embodiment was performed except that the SiH ₄ gas flow rate and the CH ₄ gas flow rate were changed according to the flow rate change pattern of FIG. A triple-type solar cell was manufactured in the same manner as in No. 30, and in the same procedure. This solar cell (SC ratio 30-1)
I will call it.

<Comparative Example 30-2> When forming the third i-type layer in FIG. 15, except that the μW power was changed to 0.5 W / cm ³ , the triple method was performed by the same method and the same procedure as in Example 30. A solar cell was fabricated. This solar cell (SC ratio 30-2)
I will call it.

<Comparative Example 30-3> In forming the third i-type layer of FIG. 15, a triple method was performed in the same manner and in the same procedure as in Example 30 except that the RF power was set to 0.15 W / cm ^3. A solar cell was fabricated. This solar cell (SC ratio 30-
Let's call it 3).

[0352] <Comparative Example 30-4> forming the third i-type layer in FIG. 15, except that the μW power 0.5 W / cm ^3, the RF power to 0.55 W / cm ³ Example 30 A triple-type solar cell was produced in the same manner and in the same procedure. This solar cell is referred to as (SC ratio 30-4).

<Comparative Example 30-5> When forming the third i-type layer in FIG. 15, a triple type i-type layer was formed in the same manner and in the same procedure as in Example 30 except that the pressure in the deposition chamber was set to 0.08 Torr. A solar cell was manufactured. This solar cell (SC ratio 30-
Let's call it 5).

The initial photoelectric conversion efficiency and durability characteristics of these fabricated triple solar cells were measured in the same manner as in Example 17, and it was found that (SC Ex 30) was a conventional triple solar cell (SC ratio 30-1). ) To (SC ratio 30-5) were found to have better initial photoelectric conversion efficiency and durability.

<< Example 31 >> FIG. 1 was manufactured using the manufacturing apparatus of FIG. 12 using the microwave plasma CVD method of the present invention.
Seven triple solar cells were fabricated, modularized, and applied to a power generation system.

A 50 × 50 mm ² triple solar cell (SC Ex.
0) were produced. An adhesive sheet made of EVA (ethylene vinyl acetate) is placed on an aluminum plate having a thickness of 5.0 mm, a nylon sheet is placed on the adhesive sheet, and the solar cells produced are further arranged on the adhesive sheet, and serialization and parallelization are performed. went. An EVA adhesive sheet was placed thereon, and a fluororesin sheet was further placed thereon, followed by vacuum lamination to form a module.

The initial photoelectric conversion efficiency of the manufactured module was measured in the same manner as in Example 17. Connect the fabricated module to the circuit showing the power generation system of FIG.
An external light that lights up at night was used for the load. The entire system was powered by the battery and the power of the module, and the module was installed at an angle that could best collect sunlight. After one year, the photoelectric conversion efficiency was measured, and the light deterioration rate (photoelectric conversion efficiency after one year / initial photoelectric conversion efficiency) was obtained. This module will be called (MJ Actual 31).

<Comparative Example 31-1> 65 conventional triple-type solar cells (SC ratio 30-X) (X: 1 to 5) were each manufactured and modularized in the same manner as in Example 31. This module is called (MJ ratio 31-X).

The initial photoelectric conversion efficiency and the photoelectric conversion efficiency after one year had elapsed were measured under the same conditions, the same method, and the same procedure as in Example 31, and the light deterioration rate was obtained. As a result, (MJ ratio 31-
The light degradation rate of (X) was as follows with respect to (MJ Actual 31).

[0360] From the above results, it was found that the solar cell module of the present invention had more excellent light degradation characteristics than the conventional solar cell module.

<Embodiment 32> In this embodiment, the i-type layer contains P
And a B atom were introduced to produce the solar cell of FIG. 1 having a p-type layered structure.

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

Next, the raw material gas supply device 200 shown in FIG.
A semiconductor layer was formed on the reflection-enhancing layer by a manufacturing apparatus using a glow discharge decomposition method including the deposition apparatus 1200 shown in FIG.

After preparation for film formation was completed in the same manner as in Example 1, n-type, i-type and p-type semiconductor layers were formed on the substrate 1204. The SiH ₄ gas and CH ₄ gas were mixed at a distance of m from the deposition chamber.

To form the n-type layer, the auxiliary valve 120
8. The valve 2003 is gradually opened, H ₂ gas is introduced into the deposition chamber 1201 through the gas introduction pipe, and the mass flow controller 2013 is set so that the H ₂ gas flow rate becomes 50 sccm. The conductance valve was adjusted so that the pressure became 0 Torr while watching the vacuum gauge 1202, and the heater 1205 was set so that the temperature of the substrate 1204 became 350 ° C. When the substrate was sufficiently heated, the valves 2001 and 2004 were gradually opened, and SiH ₄ gas and PH ₃ / H ₂ gas were supplied to the deposition chamber 1.
It flowed into 201. At this time, the flow rate of the SiH ₄ gas is 2
sccm, H ₂ gas flow rate is 100 sccm, PH ₃ / H ₂
Each mass flow controller 2011, 2013, 2014 adjusted the gas flow rate to 20 sccm. The opening of the conductance valve 1207 was adjusted while watching the vacuum gauge 1202 so that the pressure in the deposition chamber 1201 became 1.0 Torr. Confirm that the shutter 1215 is closed, and reduce the power of the RF power supply to 7 mW / c.
m ³ , and RF power was introduced into the bias bar 1214 to generate glow discharge. The shutter is opened, and the formation of an n-type layer on the substrate 1204 is started.
When the mold layer was formed, 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. The valves 2001 and 2004 are closed to stop the flow of the SiH ₄ gas and PH ₃ / H ₂ gas into the deposition chamber 1201, and the H ₂ gas is continuously flown into the deposition chamber 1201 for 5 minutes. After closing, the inside of the deposition chamber 1201 and the inside of the gas pipe were evacuated.

Next, to manufacture an i-type layer, the valve 20
03 was gradually opened, H ₂ gas was introduced into the deposition chamber 1201, and the mass flow controller 2013 adjusted the flow rate of H ₂ gas to 300 sccm. Adjusting the conductance valve while watching the vacuum gauge 1202 so that the pressure in the deposition chamber becomes 0.01 Torr.
The heater 1205 is set so that the temperature of the substrate becomes 350 ° C.
001, 2002, 2004, 2005 are gradually opened, and SiH ₄ gas, CH ₄ gas, PH ₃ / H ₂ gas, B ₂ H ₆
/ H ₂ gas was introduced into the deposition chamber 1201. At this time,
SiH ₄ gas flow rate 100 sccm, CH ₄ gas flow rate 30
sccm, H ₂ gas flow rate is 300 sccm, PH ₃ / H ₂
Gas flow rate ₂ sccm, B ₂ H ₆ / H ₂ gas flow rate 5 sccm
It adjusted with each mass flow controller so that it might become. The opening of the conductance valve 1207 was adjusted while watching the vacuum gauge 1202 so that the pressure in the deposition chamber 1201 became 0.01 Torr.

Next, the power of the RF power supply 1203 is reduced to 0.40
W / cm ³ was set and applied to the bias bar 1214.
Thereafter, the electric power of a μW power supply (not shown) was increased to 0.20 W / cm ^3.
And a μW power was introduced into the deposition chamber 1201 through the dielectric window 1213 to generate glow discharge, the shutter was opened, and the i-type layer was formed on the n-type layer. Using a computer connected to the mass flow controller, the Si flow was changed in accordance with the flow rate change pattern shown in FIG.
The flow rate of H ₄ gas and CH ₄ gas was changed, and the layer thickness was 300 nm.
When the i-type layer was formed, the shutter was closed and the μW
The power supply was turned off to stop glow discharge, the RF power supply 1203 was turned off, and the fabrication of the i-type layer was completed. Valve 2001, 200
2, 2004 and 2005 are closed, and SiH ₄ gas, CH ₄ gas, PH ₃ / H ₂ gas, B ₂ H ₆ /
Stopping the flow of H ₂ gas for 5 minutes, H ₂ into the deposition chamber 1201
After continuing the gas flow, the inside of the deposition chamber 1201 and the gas pipe were evacuated by surrounding the valve 2003.

To form a p-type layer, the valve 2003 was gradually opened, and H ₂ gas was introduced into the deposition chamber 1201.
The mass flow controller 2013 adjusted the H ₂ gas flow rate to 300 sccm. The conductance valve is adjusted while watching the vacuum gauge 1202 so that the pressure in the deposition chamber becomes 0.02 Torr, and the heater 1205 is set so that the temperature of the substrate 1204 becomes 200 ° C. When the substrate is sufficiently heated, the temperature is further increased. Valve 200
1, 2002 and 2005 are gradually opened, and SiH ₄ gas, CH ₄ gas, H ₂ gas and B ₂ H ₆ / H ₂ gas are deposited in the deposition chamber 1
It flowed into 201. At this time, the SiH ₄ gas flow rate is 1
0 sccm, CH ₄ gas flow rate 5 sccm, H ₂ gas flow rate 300 sccm, B ₂ H ₆ / H ₂ gas flow rate 10 sccc
m was adjusted by each mass flow controller. The opening of the conductance valve 1207 was adjusted while watching the vacuum gauge 1202 so that the pressure in the deposition chamber 1201 became 0.02 Torr.

The μW power supply was set to 0.30 W / cm ³ ,
ΜW power is introduced into the deposition chamber 1201 through the dielectric window 1213 to generate glow discharge, and the shutter 1215
Was opened to start forming a lightly doped layer (B layer) on the i-type layer. When the B layer having a thickness of 3 nm was formed, the shutter was closed, the μW power was turned off, and the glow discharge was stopped. The valves 2001, 2002, 2005 are closed and the deposition chamber 12 is closed.
01 in F of SiH ₄ gas, CH ₄ stop gas, the flow of B ₂ H ₆ / H ₂ gas, after continued to flow for 5 minutes, the deposition chamber 1201 F H ₂ gas, closing the valve 2003, the deposition chamber 120
1 and 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 1201,
It was adjusted with a mass flow controller so as to be 000 sccm. While adjusting the conductance valve while watching the vacuum gauge 1202 so that the pressure in the deposition chamber becomes 0.02 Torr, the power of the μW power supply is set to 0.20 W / cm ³ , and μW power is introduced into the deposition chamber 1201. Glow discharge was generated, the shutter 1215 was opened, and the formation of a layer of boron (B) (A layer) on the B layer was started. After 6 seconds, the shutter was closed, the μW power was turned off, and glow discharge was stopped. The valve 2005 is closed and the deposition chamber 120 is closed.
After stopping the introduction of the B ₂ H ₆ / H ₂ gas into the chamber 1 and continuing the flow of the H ₂ gas into the deposition chamber 1201 for 5 minutes, the valve 2003
Was closed, and the inside of the deposition chamber 1201 and the inside of the gas pipe were evacuated.

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

The auxiliary valve 1208 was closed, the leak valve 1209 was opened, and the deposition chamber 1201 was leaked.

Next, on the p-type layer, ITO (In ₂ O ₃ + SnO ₂ ) having a thickness of 80 nm as a transparent electrode and chromium (Cr) having a thickness of 10 μm as a current collecting electrode were formed by a normal vacuum deposition method. Evaporated. Thus, the fabrication of the non-single-crystal silicon carbide solar cell was completed. This solar cell is referred to as (SC Ex 32). Table 15 shows the conditions for forming the n-type layer, the i-type layer, and the p-type layer.

<Comparative Example 32-1> When forming the i-type layer, the flow rate of the SiH ₄ gas and the flow rate of the CH ₄ gas were changed as shown in FIG.
Except for adjusting by each mass flow controller according to the flow rate pattern shown in the above, on the substrate under the same conditions and the same procedure as in Example 32, a reflective layer, a reflection increasing layer, an n-type layer, an i-type layer, a p-type layer, a transparent An electrode and a current collecting electrode were formed to produce a solar cell. This solar cell is referred to as (SC ratio 32-1).

<Comparative Example 32-2> In forming the i-type layer,
A reflection layer, a reflection enhancement layer, an n-type layer, an i-type layer, a p-type layer, a transparent electrode, and a collector were formed on a substrate in the same manner as in Example 32 except that no PH ₃ / H ₂ gas was allowed to flow. Electrodes were formed to produce a solar cell. This solar cell (SC ratio 32-2)
I will call it.

<Comparative Example 32-3> When forming the i-type layer,
B2 _H 6 _/ H method similar to Example 32 from ₂ except that no flow of gas, on the substrate by the same procedure, reflecting layer, reflection enhancing layer, n
A solar cell was manufactured by forming a mold layer, an i-type layer, a p-type layer, a transparent electrode, and a current collecting electrode. This solar cell (SC ratio 32-
Let's call it 3).

<Comparative Example 32-4> A reflective layer was formed on a substrate under the same conditions and in the same procedure as in Example 32 except that the μW power was changed to 0.5 W / cm ³ when forming the i-type layer. , A reflection increasing layer, an n-type layer, an i-type layer, a p-type layer, a transparent electrode, and a current collecting electrode were formed to produce a solar cell. This solar cell (SC
Ratio 32-4).

<Comparative Example 32-5> A reflective layer was formed on a substrate under the same conditions and under the same procedure as in Example 32 except that the RF power was changed to 0.15 W / cm ³ when forming the i-type layer. , A reflection increasing layer, an n-type layer, an i-type layer, a p-type layer, a transparent electrode, and a current collecting electrode were formed to produce a solar cell. This solar cell is (S
C ratio 32-5).

<Comparative Example 32-6> In forming the i-type layer, μW power was 0.5 W / cm ³ and RF power was 0.55.
A reflection layer, a reflection enhancement layer, an n-type layer, an i-type layer, a p-type layer, a transparent electrode, and a current collecting electrode were formed on a substrate under the same conditions and in the same procedure as in Example 32, except that W / cm ³ was used. The solar cell was formed by forming. This solar cell is referred to as (SC ratio 32-6).

<Comparative Example 32-7> Except that the pressure in the deposition chamber was set to 0.08 Torr when forming the i-type layer,
Under the same conditions and in the same procedure as in Example 32, a reflective layer, a reflection increasing layer, an n-type layer, an i-type layer, a p-type layer, a transparent electrode,
A current collecting electrode was formed to produce a solar cell. This solar cell is referred to as (SC ratio 32-7).

Measurement of the initial photoelectric conversion efficiency (photovoltaic power / incident light power) and durability characteristics of the solar cells (SC Ex 32) and (SC Comp. 32-1) to (SC Comp. 32-7) prepared above. Done.

As a result of the measurement, the initial photoelectric conversion efficiencies of (SC ratio 32-1) to (SC ratio 32-7) for the solar cell of (SC Ex 32) were as follows.

(SC ratio 32-1) 0.78 times (SC ratio 32-2) 0.77 times (SC ratio 32-3) 0.76 times (SC ratio 32-4) 0.65 times (SC ratio) 32-5) 0.77 times (SC ratio 32-6) 0.69 times (SC ratio 32-7) 0.86 times The durability of the solar cell (SC actual 32) of this example is (SC ratio 32). (SC ratio 32)
-1) to (SC ratio 32-7), the decrease in photoelectric conversion efficiency was as follows.

(SC ratio 32-1) 0.79 times (SC ratio 32-2) 0.78 times (SC ratio 32-3) 0.77 times (SC ratio 32-4) 0.64 times (SC ratio) 32-5) 0.77 times (SC ratio 32-6) 0.65 times (SC ratio 32-7) 0.70 times In addition, solar cells (SC actual 32) manufactured in the same manner as in Example 1 I of SC ratio 32-1) to (SC ratio 32-7)
When the change in the band gap in the layer thickness direction in the mold layer was determined, (SC actual 32), (SC ratio 32-2) to (SC
In the solar cell of the ratio (32-7), the position of the minimum value of the band gap is offset from the center of the i-type layer toward the p / i interface, and in the solar cell of (SC ratio 32-1), the band gap is Is n / n from the center of the i-type layer.
It was confirmed that it was offset in the direction of the i interface.

Further, the composition analysis of P- and B-atoms in the i-type layers of the solar cell (SC Ex 32) and (SC Comp. 32-1) to (SC Comp. As a result of using an analyzer (IMS-3F manufactured by CAMECA), P
Atoms and B atoms are uniformly distributed in the layer thickness direction,
The composition ratio was as follows.

(SC Ex 32) P / (Si + C) ３3 ppm B / (Si + C) 〜１０10 ppm (SC ratio 32-1) P / (Si + C) ３3 ppm B / (Si + C) 〜 10 ppm (SC ratio 32-2) P / (Si + C) DB / (Si + C) -10 ppm (SC ratio 32-3) P / (Si + C) -3 ppm B / (Si + C) D. (SC ratio 32-4) P / (Si + C) ４4 ppm B / (Si + C) １８18 ppm (SC ratio 32-5) P / (Si + C) ３3 ppm B / (Si + C) 〜１０10 ppm (SC ratio 32-6) P / (Si + C) ４4 ppm B / (Si + C) １７17 ppm (SC ratio 32-7) P / (Si + C) ３3 ppm B / (Si + C) 〜１０10 ppm N. D. : Below the detection limit <Comparative Example 32-8> μW introduced when forming an i-type layer
The power and RF power were changed in various ways, and the other conditions were the same as in Example 3.
In the same manner as in Example 2, some non-single-crystal silicon carbide solar cells were manufactured.

The deposition rate does not depend on the RF power, and becomes constant when the μW power is 0.32 W / cm ³ or more, and this power decomposes 100% of the SiH ₄ gas and the CH ₄ gas as the source gases. Do you get it.

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

[0389] In the formation of the i-type layer in <Comparative Example 32-9> Example 32, to change the flow rate of the gas introduced into the deposition chamber SiH ₄ gas 50 sccm, a CH ₄ gas 10 sccm, H ₂
No gas was introduced, and several non-single-crystal silicon carbide solar cells were fabricated with various μW power and RF power. Other conditions were the same as in Example 32.

When the relationship between the deposition rate, μW power, and RF power was examined, the deposition rate did not depend on the RF power as in Comparative Example 32-8, and was constant when the μW power was 0.18 W / cm ³ or more. It was found that the SiH ₄ gas and the CH ₄ gas, which are the source gases, were decomposed 100% with this μW power.

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

<Comparative Example 32-10> In forming the i-type layer in Example 32, the flow rate of the gas introduced into the deposition chamber was changed to SiH _4.
The gas power was changed to 200 sccm for gas, 50 sccm for CH ₄ gas, and 500 sccm for H ₂ gas.
Several non-single-crystal silicon carbide solar cells were fabricated with various F powers. Other conditions were the same as in Example 32. When the relationship between the deposition rate, the μW power, and the RF power was examined, the deposition rate was constant at 0.65 W / cm ³ or more without depending on the RF power as in Comparative Example 32-8. 100% of SiH ₄ gas and CH ₄ gas as gas
It was found to be decomposed.

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
ΜW power for decomposing gas by 100% (0.65 W / c
m ³ ) or less and the RF power was larger than the μW power, it was found that the initial photoelectric conversion efficiency was greatly improved.

<Comparative Example 32-11> In forming the i-type layer in Example 32, the pressure in the deposition chamber was increased from 3 mTorr to 20 m / s.
Various conditions were changed up to 0 mTorr, and other conditions were the same as in Example 32.
Several non-single-crystal silicon carbide solar cells were fabricated in the same manner as in Example 1. When the initial photoelectric conversion efficiency of the solar cell when irradiating AM1.5 light was measured, the pressure was 50 mTorr.
At r or more, it was found that the initial photoelectric conversion efficiency was greatly reduced.

As described above, <Comparative Example 32-1> to <Comparative Example 32
-11>, the solar cell of the present invention (SC Ex.
2) was found to have more excellent characteristics than the conventional solar cells (SC ratio 32-1) to (SC ratio 32-7). At a pressure of 50 mTorr or less, the raw material gas flow rate, substrate temperature, etc. It has been demonstrated that excellent characteristics can be obtained without depending on the manufacturing conditions.

Example 33 In Example 32, several solar cells were manufactured 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, and initializing the solar cell. The photoelectric conversion efficiency and the durability were examined in the same manner as in Example 32. At this time, the 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 32. In this example, the solar cell having the band diagram shown in FIG. 9 was manufactured by changing the change pattern of the SiH ₄ gas flow rate and the CH ₄ gas flow rate.

[0397] Table 16 shows the results obtained by examining the initial photoelectric conversion efficiency and durability characteristics of these manufactured solar cells. Here, each value was standardized on the basis of the value of (SC Ex. 33-1).

As can be seen from these results, the band gap of the i-type layer smoothly changes in the layer thickness direction regardless of the size and the change pattern of the minimum value of the band gap, and the position of the minimum value of the band gap changes. It has been found that the solar cell of the present invention, which is offset in the p / i interface direction from the center position of the i-type layer, is superior.

Example 34 In Example 32, several solar cells were produced in which the concentration and type of the valence electron controlling agent in the i-type layer were changed, and the initial photoelectric conversion efficiency and durability were the same as in Example 32. In a particular way. Example 3 except that the concentration and type of the valence electron controlling agent in the i-type layer were changed at this time.
Same as 2.

[0400] <Example 34-1> and i-type layer of the acceptor become valence electron controlling agent for the gas (B ₂ H ₆ / H ₂ gas) flow rate 1/5, the total flow rate of H ₂ Example When a solar cell (SC Ex. 34-1) which was the same as that in Example 1 was produced,
As in (SC Ex 32), a conventional solar cell (SC ratio 32-
It was found to have better initial photoelectric conversion efficiency and durability than 1) to (SC ratio 32-7).

<Example 34-2> The flow rate of the gas (B ₂ H ₆ / H ₂ gas) for the valence electron controlling agent serving as the acceptor of the i-type layer was increased by five times, and the total H ₂ flow rate was the same as in Example 32. When the same solar cell (SC Ex. 34-2) was manufactured,
As in (SC Ex 32), a conventional solar cell (SC ratio 32-
It was found to have better initial photoelectric conversion efficiency and durability than 1) to (SC ratio 32-7).

<Example 34-3> The flow rate of the gas (PH ₃ / H ₂ gas) for the valence electron controlling agent serving as the donor of the i-type layer was reduced to 1/5.
A solar cell (SC Ex. 34-3) having the same H ₂ flow rate as that of Example 32 was manufactured, and the same solar cell (SC ratio 32-1) as in (SC Ex. 32) was produced.
It was found to have better initial photoelectric conversion efficiency and durability than (SC ratio 32-7).

<Example 34-4> The flow rate of the gas (PH ₃ / H ₂ gas) for the valence electron controlling agent serving as the donor of the i-type layer was increased by five times, and the total H ₂ flow rate was the same as in Example 32. When the manufactured solar cell (SC Ex. 34-4) was manufactured, (SC Ex.
Similar to 2), conventional solar cells (SC ratio 32-1) to (S
It was found that it had better initial photoelectric conversion efficiency and durability than C ratio 32-7).

<Example 34-5> Trimethylaluminum (TMA) which is liquid at normal temperature and normal pressure is used instead of B ₂ H ₆ / H ₂ gas as a gas for a valence electron controlling agent serving as an acceptor of an i-type layer. A solar cell was manufactured. At this time, except that TMA (purity 99.99%) sealed in a liquid cylinder is gasified by bubbling with hydrogen gas and introduced into the deposition chamber, the solar cell is manufactured using the same method and procedure as in Example 32. (SC Ex. 34-5) was produced. At this time, TM
The flow rate of the A / H ₂ gas was set to 10 sccm. The manufactured solar cell (SC Ex. 34-5) is the same as the conventional solar cell (SC Comp. 32-1) to (SC Comp.
It was found to have even better initial photoelectric conversion efficiency and durability characteristics.

<Example 34-6> A solar cell using hydrogen sulfide (H ₂ S) gas instead of PH ₃ / H ₂ gas as a gas for a valence electron controlling agent serving as a donor of an i-type layer was manufactured. .
The NH ₃ / H ₂ gas cylinder of Example 32 was hydrogenated (H ₂ ) for 1 hour.
Replace the diluted H ₂ S gas (H ₂ S / H ₂₎ cylinder in 00Ppm, to prepare a solar cell (SC 34-6) using similar methods, and procedures of Example 32. At this time, the flow rate of the H ₂ S / H ₂ gas was set at 1 sccm, and the other conditions were the same as in Example 32. The manufactured solar cell (SC Ex. 34-6) has better initial photoelectric conversion efficiency and durability than the conventional solar cells (SC Comp. 32-1) to (SC Comp. 32-7), similarly to (SC Ex. 32). It has been found to have properties.

Example 35 A solar cell was manufactured in which the stacking order of the n-type layer and the p-type layer was reversed. Table 17 shows the conditions for forming the p-type layer, the i-type layer, and the n-type layer. When forming an i-type layer,
The flow rates of the SiH ₄ gas and the CH ₄ gas were changed as shown in the pattern of FIG. 13-2 so that the minimum value of the band gap was located closer to the p / i interface. The n-type layer had a laminated structure using the same method as in Example 32, and was formed using PH ₃ / H ₂ gas. The layers other than the semiconductor layer and the base were manufactured using the same conditions and the same method as in Example 32. The manufactured solar cell (SC Ex. 35) has better initial photoelectric conversion efficiency and durability characteristics than the conventional solar cells (SC Comp. 32-1) to (SC Comp. 32-7), similarly to (SC Ex. 32). It was found to have.

Example 36 A non-single-crystal silicon carbide solar cell having a region having the maximum value of the band gap of the i-type layer near the p / i interface and having a thickness of 20 nm was manufactured. The i-type layer was manufactured using the same conditions and the same method as in Example 32 except that the flow rate change pattern of the i-type layer was changed to the flow rate pattern shown in FIG. Next, composition analysis of the solar cell was performed in the same manner as in Example 32, and based on FIG.
When the change of the band gap in the thickness direction of the mold layer was examined, the result was as shown in FIG. 22-2.

The fabricated solar cell (SC Ex. 36) is (SC
As in the case of the actual solar cell 32), conventional solar cells (SC ratio 32-1) to
It was found to have better initial photoelectric conversion efficiency and durability than (SC ratio 32-7).

<Comparative Example 21> Several non-single-crystal silicon carbide solar cells were produced in which the band gap had a maximum value on the p / i interface side and the thickness of the region was variously changed.
Except for the thickness of the region, it was manufactured using the same conditions and the same method as in Example 36.

When the initial photoelectric conversion efficiency and durability characteristics of the manufactured solar cell were measured, when the thickness of the region was 1 nm or more and 30 nm or less, the solar cell of Example 32 (SC Ex.
Even better initial photoelectric conversion efficiency and durability were obtained than in 2).

Example 37 A non-single-crystal silicon carbide solar cell having a region having the maximum value of the band gap of the i-type layer near the n / i interface and having a thickness of 15 nm was manufactured. The i-type layer was fabricated using the same conditions and the same method as in Example 32 except that the flow rate change pattern of the i-type layer was changed to the flow rate pattern of FIG. Next, the composition analysis of the solar cell was performed in the same manner as in Example 32, and the change in the band gap in the thickness direction of the i-type layer was examined based on FIG.
The result was similar to -4.

The manufactured solar cell (SC Ex 37) is (SC
As in the case of the actual solar cell 32), conventional solar cells (SC ratio 32-1) to
It was found to have better initial photoelectric conversion efficiency and durability than (SC ratio 32-7).

<Comparative Example 37> There was a region having the maximum value of the band gap near the n / i interface, and several non-single-crystal silicon carbide solar cells in which the thickness of the territory was variously changed were manufactured. Except for the thickness of the region, it was manufactured using the same conditions and the same method as in Example 37.

When the initial photoelectric conversion efficiency and durability characteristics of the manufactured solar cell were measured, when the thickness of the region was 1 nm or more and 30 nm or less, the solar cell of Example 32 (SC Ex.
Even better initial photoelectric conversion efficiency and durability were obtained than in 2).

Example 38 A non-single-crystal silicon carbide solar cell in which a valence electron controlling agent was distributed in an i-type layer was manufactured. FIG. 24-1 shows a change pattern of the flow rates of the PH ₃ / H ₂ gas and the B ₂ H ₆ / H ₂ gas. At the time of fabrication, the same conditions, the same method, and the same procedure as in Example 32 were used, except that the flow rates of PH ₃ / H ₂ gas and B ₂ H ₆ / H ₂ gas were changed. The manufactured solar cell (SC Ex. 38) has better initial photoelectric conversion efficiency and durability characteristics than the conventional solar cells (SC Comp. 32-1) to (SC Comp. 32-7), similarly to (SC Ex. 1). It was found to have.

A change in the thickness direction of P atoms and B atoms contained in the i-type layer in the layer thickness direction is measured using a secondary ion mass spectrometer (SIM).
As a result of an examination using S), as shown in FIG.
It was found that at the position where the band gap was minimum, the contents of P atoms and B atoms were minimum.

Example 39 A non-single-crystal silicon carbide solar cell having an i-type layer containing oxygen atoms was manufactured. i
When forming the mold layer, in addition to the gas flowing in Example 32, O ₂
The same conditions, the same method, and the same procedure as in Example 32 were used, except that / He gas was introduced at 10 sccm into the deposition chamber.
The manufactured solar cells (SC Ex. 39) were similar to the conventional solar cells (SC Ex. 32-1) to (SC Ex.
It was found to have better initial photoelectric conversion efficiency and durability than -7). Further, when the content of oxygen atoms in the i-type layer was measured by SIMS, it was found that the content was almost uniform and 2 × 10 ¹⁹ (pieces / cm ³ ).

Example 40 A non-single-crystal silicon carbide solar cell having an i-type layer containing nitrogen atoms was manufactured. i
When forming the mold layer, NH 3 was used in addition to the gas flowing in Example 32.
_The same conditions, the same method, and the same procedure as in Example 32 were used, except that ₃ / H ₂ gas was introduced into the deposition chamber at 5 sccm. The manufactured solar cell (SC Ex 40) is similar to (SC Ex 32).
Conventional solar cells (SC ratio 32-1) to (SC ratio 32-
It was found to have better initial photoelectric conversion efficiency and durability than 7).

The content of nitrogen atoms in the i-type layer is determined by SI
As a result of examination by MS, it was contained almost uniformly, and 3 × 10 ¹⁷
(Pieces / cm ³ ).

Example 41 A non-single-crystal silicon carbide solar cell having an i-type layer containing oxygen atoms and nitrogen atoms was manufactured. In forming an i-type layer, the same procedure as in Example 32 was carried out except that O ₂ / He gas and NH ₃ / H ₂ gas were introduced at 5 sccm and 5 sccm, respectively, in the deposition chamber in addition to the gas flowing in Example 32.
The same conditions, method and procedure were used. The manufactured solar cell (SC Ex 41) has better initial photoelectric conversion efficiency and durability characteristics than the conventional solar cells (SC ratio 32-1) to (SC ratio 32-7), similarly to (SC Ex 32). It was found to have. Further, when the contents of oxygen atoms and nitrogen atoms in the i-type layer were measured by SIMS, they were almost uniformly contained, each being 1 × 10 ¹⁹ (pieces / cm ³ ) and 3 × 10
¹⁷ (pieces / cm ³ ).

Example 42 A non-single-crystal silicon carbide solar cell was manufactured in which the hydrogen content of the i-type layer was changed in accordance with the silicon content. O ₂ / He gas cylinder is SiF ₄
When the gas (purity: 99.999%) was exchanged for a cylinder and an i-type layer was formed, Si was used in accordance with the flow pattern shown in FIG.
The flow rates of H ₄ gas, CH ₄ gas, and SiF ₄ gas were changed.

The change in the band gap in the layer thickness direction of this solar cell (SC Ex. 42) was determined in the same manner as in Example 32, and the results shown in FIG. 23B were obtained.

Further, the content of hydrogen atoms and silicon atoms was analyzed in the layer thickness direction using SIMS. As a result, as shown in FIG. 23C, it was found that the hydrogen atom content had a distribution in the layer thickness direction corresponding to the silicon atom content.

The initial photoelectric conversion efficiency and durability of this solar cell (SC Ex. 42) were determined. As in the case of the solar cell of Example 32, conventional solar cells (SC ratio 32-1) to (SC ratio) were obtained.
It was found that it had better initial photoelectric conversion efficiency and durability than the ratio (32-7).

Example 43 In forming the semiconductor layer of the non-single-crystal silicon carbide solar cell of FIG. 1 by the manufacturing apparatus using the microwave plasma CVD method shown in FIG. 12, a silicon atom-containing gas (SiH ₄ gas) was used. ) And a gas containing carbon atoms (CH ₄ gas) were mixed at a distance of 1 m from the deposition chamber, and a non-single-crystal silicon carbide solar cell (SC Ex. 43) was produced in the same manner and in the same procedure as in Example 32. It was found that the manufactured solar cell (SC Ex 43) had better initial photoelectric conversion efficiency and durability than (SC Ex 32).

Example 44 A tandem solar cell having a non-single-crystal silicon carbide semiconductor layer and having a non-single-crystal silicon carbide semiconductor layer as shown in FIG. 14 was manufactured by using the manufacturing apparatus of FIG. 12 using the microwave plasma CVD method of the present invention.

First, a base was manufactured. A 50 × 50 mm ² stainless steel substrate was subjected to ultrasonic cleaning with acetone and isopropanol and dried in the same manner as in Example 32. Using a sputtering method, 0.3μ
A reflective layer of Ag (silver) was formed. At this time, the substrate temperature was set at 350 ° C., and the substrate surface was made uneven (textured). A reflection enhancement layer of ZnO (zinc oxide) having a thickness of 1.0 μm was formed thereon at a substrate temperature of 350 ° C.

Next, a first n-type layer was formed on a substrate by the same procedure and in the same manner as in Example 32, and a first i-type layer, a first p-type layer, and a second n-type layer were formed. Mold layer, second i-type layer, second
Were sequentially formed. When forming the second i-type layer,
SiH accordance flow change pattern as shown in FIG. 13-1 ₄
The gas flow rate and the CH ₄ gas flow rate were changed, and the second p-type layer had a laminated structure as in Example 32.

Next, as in Example 32, an 80 nm-thick ITO (In ₂ O ₃₎ layer was formed on the second p-type layer as a transparent electrode.
+ SnO ₂ ) and chromium (Cr) having a layer thickness of 10 μm as a current collecting electrode were deposited by a normal vacuum deposition method.

Thus, the manufacture of the tandem solar cell using the microwave plasma CVD method is completed. This solar cell is referred to as (SC Ex. 44), and Table 18 shows the manufacturing conditions of each semiconductor layer.

<Comparative Example 44-1> An example was made except that the SiH ₄ gas flow rate and the CH ₄ gas flow rate were changed according to the flow rate change pattern shown in FIG. 13-2 when forming the second i-type layer in FIG. A tandem solar cell was manufactured in the same manner and by the same procedure as forty-fourth. This solar cell (SC ratio 44-1)
I will call it.

<Comparative Example 44-2> When forming an i-type layer,
A reflection layer, a reflection enhancement layer, an n-type layer, an i-type layer, a p-type layer, a transparent electrode, and a collector were formed on a substrate in the same manner and in the same procedure as in Example 44 except that no PH ₃ / H ₂ gas was passed. Electrodes were formed to produce a solar cell. This solar cell (SC ratio 44-2)
I will call it.

<Comparative Example 44-3> In forming the i-type layer,
B2 _H 6 _/ H method similar to Example 44 from ₂ except that no flow of gas, on the substrate by the same procedure, reflecting layer, reflection enhancing layer, n
A solar cell was manufactured by forming a mold layer, an i-type layer, a p-type layer, a transparent electrode, and a current collecting electrode. This solar cell (SC ratio 44-
Let's call it 3).

<Comparative Example 44-4> In forming the second i-type layer of FIG. 14, a tandem method was performed in the same manner as in Example 44, except that the μW power was changed to 0.5 W / cm ^3. A solar cell was fabricated. This solar cell (SC ratio 44-4)
I will call it.

<Comparative Example 44-5> In forming the second i-type layer in FIG. 14, a tandem method was performed in the same manner as in Example 44, except that the RF power was changed to 0.15 W / cm ^3. A solar cell was fabricated. This solar cell (SC ratio 44-
Let's call it 5).

[0436] <Comparative Example 44-6> when forming the second i-type layer in FIG. 14, except that the μW power 0.5 W / cm ^3, the RF power to 0.55 W / cm ³ Example 44 A tandem solar cell was manufactured in the same manner and in the same procedure as in the above. This solar cell will be referred to as (SC Comp. 44-6).

<Comparative Example 44-7> A tandem type is formed by the same method and in the same procedure as in Example 44 except that the pressure in the deposition chamber is set to 0.1 Torr when forming the second i-type layer in FIG. A solar cell was manufactured. This solar cell (SC ratio 44-
7).

The initial photoelectric conversion efficiency and durability of these tandem solar cells were measured in the same manner as in Example 32. The result (SC Ex. 44) was that of a conventional tandem solar cell (SC ratio 44-1). ) To (SC ratio 44-7) were found to have better initial photoelectric conversion efficiency and durability.

Example 45 Using the manufacturing apparatus of FIG. 12 using the microwave plasma CVD method of the present invention, a triple solar cell having a non-single-crystal silicon carbide semiconductor layer of FIG. 15 was manufactured.

First, a substrate was manufactured. A 50 × 50 mm ² stainless steel substrate was subjected to ultrasonic cleaning with acetone and isopropanol and dried in the same manner as in Example 32. Using a sputtering method in the same manner as in Example 44, 0.3 μm Ag (silver) was applied on the surface of a stainless steel substrate at a substrate temperature of 350 ° C.
To form a reflective layer and make the substrate surface uneven (texture)
I made it. On top of that, a substrate temperature of 350 ° C. and 1.0 μm of Zn
An O (zinc oxide) reflection increasing layer was formed.

First, instead of the NH ₃ / H ₂ gas cylinder, G
An eH ₄ gas (99.999% purity) cylinder was connected, and preparation for film formation was completed by the same method and procedure as in Example 32.

A first n-type layer was formed on a substrate by the same procedure and in the same manner as in Example 32, and 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, a third i-type layer, and a third p-type layer were sequentially formed.

When forming the third i-type layer, the flow rate of SiH ₄ gas and C
The H ₄ gas flow rate was changed. The second p-type layer and the third p-type layer had a laminated structure as in Example 32.

Next, as in Example 32, an 80 nm-thick ITO (In ₂ O ₃₎ was formed on the third p-type layer as a transparent electrode.
+ SnO ₂ ) and chromium (Cr) having a layer thickness of 10 μm as a current collecting electrode were deposited by a normal vacuum deposition method.

The fabrication of the triple type solar cell using the microwave plasma CVD method was completed. This solar cell is referred to as (SC Ex. 45), and Table 19 summarizes the manufacturing conditions of each semiconductor layer.

<Comparative Example 45-1> In forming the third i-type layer in FIG. 15, the embodiment was performed except that the SiH ₄ gas flow rate and the CH ₄ gas flow rate were changed in accordance with the flow rate change pattern in FIG. A triple solar cell was fabricated in the same manner and by the same procedure as in Forty-Five. This solar cell (SC ratio 45-1)
I will call it.

<Comparative Example 45-2> In forming the third i-type layer in FIG. 15, except that no PH ₃ / H ₂ gas was flowed, a method similar to that in Example 45 and a similar procedure were used to form a film on a substrate. , A reflective layer, a reflection increasing layer, an n-type layer, an i-type layer, a p-type layer, a transparent electrode, and a current collecting electrode were formed to produce a solar cell. This solar cell is (S
C ratio 45-2).

<Comparative Example 45-3> A substrate was formed in the same manner and in the same procedure as in Example 45 except that no B ₂ H ₆ / H ₂ gas was supplied when forming the third i-type layer in FIG. Above, a reflective layer,
A solar cell was manufactured by forming a reflection increasing layer, an n-type layer, an i-type layer, a p-type layer, a transparent electrode, and a current collecting electrode. This solar cell is referred to as (SC ratio 45-3).

<Comparative Example 45-4> In forming the third i-type layer of FIG. 15, a triple method was performed in the same manner and in the same procedure as in Example 45 except that the μW power was changed to 0.5 W / cm ^3. A solar cell was fabricated. This solar cell (SC ratio 45-4)
I will call it.

<Comparative Example 45-5> When forming the third i-type layer in FIG. 15, except that the RF power was set to 0.15 W / cm ³ , a triple method was performed by the same method and the same procedure as in Example 45. A solar cell was fabricated. This solar cell (SC ratio 45-
Let's call it 5).

[0451] <Comparative Example 45-6> forming the third i-type layer in FIG. 15, except that the μW power 0.5 W / cm ^3, the RF power to 0.55 W / cm ³ Example 45 A triple-type solar cell was produced in the same manner and in the same procedure. This solar cell is referred to as (SC ratio 45-6).

<Comparative Example 45-7> When forming the third i-type layer in FIG. 15, a triple type i-type layer was formed in the same manner as in Example 45 except that the pressure in the deposition chamber was set to 0.08 Torr. A solar cell was manufactured. This solar cell (SC ratio 45-
7).

The initial photoelectric conversion efficiency and durability of these fabricated triple solar cells were measured in the same manner as in Example 32. The result (SC Ex 45) was that of a conventional triple solar cell (SC ratio 45-1). ) To (SC ratio 45-7) were found to have better initial photoelectric conversion efficiency and durability.

<< Embodiment 46 >> Using the manufacturing apparatus of FIG. 12 using the microwave plasma CVD method of the present invention, FIG.
Seven triple solar cells were fabricated, modularized, and applied to a power generation system.

A 50 × 50 mm ² triple type solar cell (SC Ex.
5) were produced in 65 pieces. An adhesive sheet made of EVA (ethylene vinyl acetate) is placed on an aluminum plate having a thickness of 5.0 mm, a nylon sheet is placed on the adhesive sheet, and the solar cells produced are further arranged on the adhesive sheet, and serialization and parallelization are performed. went. An EVA adhesive sheet was placed thereon, and a fluororesin sheet was further placed thereon, followed by vacuum lamination to form a module.

The initial photoelectric conversion efficiency of the manufactured module was measured in the same manner as in Example 32. Connect the fabricated module to the circuit showing the power generation system of FIG.
An external light that lights up at night was used for the load. The entire system was powered by the battery and the power of the module, and the module was installed at an angle that could best collect sunlight. After one year, the photoelectric conversion efficiency was measured, and the light deterioration rate (photoelectric conversion efficiency after one year / initial photoelectric conversion efficiency) was obtained. This module is called (MJ actual 46).

<Comparative Example 46-1> Sixty-five conventional triple solar cells (SC ratio 45-X) (X: 1 to 7) were manufactured, and were modularized in the same manner as in Example 46. This module is called (MJ ratio 46-X).

The initial photoelectric conversion efficiency and the photoelectric conversion efficiency after one year had elapsed were measured under the same conditions, the same method, and the same procedure as in Example 46, and the light deterioration rate was obtained. As a result, (MJ ratio 46-
The light degradation rate of (X) was as follows with respect to (MJ Actual 46).

[0459] From the above results, it was found that the solar cell module of the present invention had more excellent light degradation characteristics than the conventional solar cell module.

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

[0461]

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

The conversion efficiency of the photovoltaic device of the present invention is improved when the irradiation light is weak. The photovoltaic element of the present invention is one in which the photoelectric conversion efficiency does not easily decrease when annealing is performed under vibration for a long time.

Further, according to the method of manufacturing a photovoltaic device of the present invention, a photovoltaic device having the above-mentioned effects can be formed with a high yield.

[0464] In addition, the power generation system using the photovoltaic element of the present invention exhibits excellent power 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]

[Table 14]

[Table 15]

[Table 16]

[Table 17]

[Table 18]

[Table 19]

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a layer configuration 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 a photovoltaic device manufacturing apparatus of the present invention.

FIG. 5 is a graph showing a flow pattern of SiH ₄ and CH ₄ gas when an i-type layer is formed.

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

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

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

FIG. 9 is a conceptual diagram showing a change in a band gap in a layer thickness direction.

FIG. 10 is a diagram showing a change in a SiH ₄ and CH ₄ gas flow rate pattern and a band gap in a layer thickness direction when an i-type layer is formed.

FIG. 11 shows B ₂ H ₆ / H ₂ gas and PH ₃ / H at the time of forming an i-type layer.
₂ is a graph showing a gas flow pattern and distribution of B atoms and P atoms in an i-type layer in a layer thickness direction.

FIG. 12 is a conceptual diagram showing another example of the photovoltaic device manufacturing apparatus of the present invention.

FIG. 13 is a graph showing a flow pattern of SiH ₄ and CH ₄ gas when an i-type layer is formed.

FIG. 14 is a schematic cross-sectional view illustrating a layer configuration of a tandem solar cell.

FIG. 15 is a schematic cross-sectional view illustrating a layer configuration of a triple solar cell.

FIG. 16 is a block diagram showing a power generation system of the present invention.

FIG. 17 shows a change pattern of a gas flow rate and i in forming an i-type layer.
5 is a graph showing a band gap change and a hydrogen content distribution in a mold layer.

FIG. 18 is a graph showing the relationship between μW power and deposition rate.

FIG. 19 is a graph showing dependence of initial photoelectric conversion efficiency on μW power and RF power.

FIG. 20 is a graph showing pressure dependence of initial photoelectric conversion efficiency.

FIG. 21 is a schematic view showing a cross-sectional TEM image of a p-type layer.

FIG. 22 is a view showing a change in a SiH ₄ and CH ₄ gas flow rate pattern and a band gap in a layer thickness direction when an i-type layer is formed.

FIG. 23 is a graph showing a gas flow pattern at the time of forming an i-type layer, a change in band gap and a distribution of hydrogen content in the i-type layer.

FIG. 24 shows B ₂ H ₆ / H ₂ gas and PH ₃ / H at the time of forming an i-type layer.
₂ is a graph showing a gas flow pattern and distribution of B atoms and P atoms in an i-type layer in a layer thickness direction.

[Explanation of symbols]

Reference Signs List 101 conductive substrate 102 n-type layer (or p-type layer) 103 i-type layer 104 p-type layer (or n-type layer) 105 transparent electrode 106 current collecting electrode 311, 321, 331, 341, 351, 361, 3
71 i-type layer whose band gap changes 312,322,332,333,342,343,3
52, 353, 362, 372, 373 i-type layer having a constant band gap 400, 1200 Deposition apparatus 401, 1201 Deposition chamber 402, 1202 Vacuum gauge 403, 1203 RF power supply 404, 1204 Base 405, 1205 Heater 407, 1207 Conductance Valve 408, 1208 Auxiliary valve 409, 1209 Leak valve 410 RF electrode 411 Gas inlet tube 1212 Waveguide 1213 Dielectric window 1214 Bias rod 2000 Source 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 Yuzo Koda Canon Inc. 3- 30-2 Shimomaruko, Ota-ku, Tokyo (72) Inventor Naoto Okada 3-30-2 Shimomaruko 3-chome, Ota-ku, Tokyo Canon Inc. (72) Inventor Fukasho Matsuyama 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-63-220582 (JP, A) JP-A-63-224371 (JP, A JP-A-59-971 (JP, A) JP-A-3-131072 (JP, A) JP-A-3-208376 (JP, A) JP-A-3-214676 (JP, A) JP-A 64-64 71181 (JP, A) JP-A-59-124772 (JP, A) JP-A-63-55982 (JP, A) JP-A-62-179164 (JP, A) JP-A-3-4569 (JP, A) JP-A-3-19374 (JP, A) JP-A-4-188774 (JP, A) JP-A-4-233282 (JP, A) U.S. Pat. No. 4,985,954 (US, A) Technical Digest of the Int ernation al PVSEC-5 A-IIp-2 p. 529-532 (1990) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 31/04

Claims (17)

(57) [Claims] 1. A photovoltaic device comprising at least a p-type layer, an i-type layer, and an n-type layer, which are made of a silicon-based non-single-crystal semiconductor material, wherein the i-type layer has at least containing and carbon atoms, the band gap changes in the thickness direction of the i-type layer, and the valence control agent comprising the valence control agent and an acceptor which serves as a donor to the i-type layer is doped, the i A photovoltaic device, wherein the content of the valence electron controlling agent is larger in the vicinity of the interface between the i-type layer and the p-type layer and / or the n-type layer than in the i-type layer. 2. A region having a maximum band gap at at least one of an interface between the i-type layer and the p-type layer or an interface between the n-type layer and the i-type layer; the photovoltaic element according to claim 1, wherein the layer thickness of region values is 1nm or more 30nm or less. Wherein the valence control agent serving as the donor is a periodic table Group III element, the acceptor become valence <br/> electronic control agent, the group V of the periodic table or, Group VI The photovoltaic device according to claim 1, wherein 4. The photovoltaic device according to claim 1, wherein the valence electron controlling agent changes in a layer thickness direction inside the i-type layer. 5. The photovoltaic device according to claim 1, wherein the valence electron controlling agent is distributed more in places where the carbon content is high and less in places where the carbon content is low. 6. The photovoltaic device according to claim 1, wherein the i-type layer contains oxygen atoms and / or nitrogen atoms. 7. A photovoltaic device according to claim 6, wherein the content of said oxygen atoms and / or nitrogen atoms are characterized by increases and decreases in response to the content of carbon atoms. 8. The hydrogen content of the i-type layer is as follows:
2. The photovoltaic device according to claim 1, wherein the photovoltaic device changes according to the content of silicon atoms. 9. At least one of the p-type layer and the n-type layer includes a layer mainly composed of Group III or Group V of the periodic table, and a silicon atom containing a valence electron controlling agent and being mainly composed of silicon. The photovoltaic device according to claim 1, wherein the photovoltaic device has a laminated structure with a layer to be formed. 10. The photovoltaic device according to claim 9, wherein the thickness of the layer mainly composed of Group III or Group V of the periodic table is 1 nm or less. 11. The photovoltaic device of claim 1, wherein the position of the minimum value of the band gap is formed offset to the p-type layer closer to the center position of the i-type layer. 12. A p-type layer, an i-type layer, and an n-type layer, which are made of a silicon-based non-single-crystal semiconductor material, are laminated at least, and the i-type layer contains silicon atoms and carbon atoms;
In a method of manufacturing a photovoltaic device in which a band gap changes in a thickness direction of the i-type layer, the i-type layer includes at least a silicon atom-containing gas, a carbon atom-containing gas, and a valence electron serving as a donor. Using a source gas containing a gas containing a control agent, and a gas containing a valence electron control agent to be an acceptor,
Formed by plasma CVD and used as the donor
Becomes a gas containing a valence electron control agent and an acceptor
A photovoltaic device characterized in that a supply amount of a gas containing a valence electron controlling agent is made larger in the vicinity of an interface between the i-type layer and the p-type layer and / or the n-type layer than in other portions. Device manufacturing method. 13. The i-type layer may be a microwave plasma CV.
The magnitude of the microwave energy to be applied, which is formed by the method D, is lower than the microwave energy for decomposing the raw material gas by 100%, and the RF energy is applied.
13. The method according to claim 12, wherein the magnitude of the F energy is higher than the microwave energy. 14. The gas containing a valence electron controlling agent,
13. The method for manufacturing a photovoltaic device according to claim 12, wherein the photovoltaic element is supplied more in a narrow band gap and less in a wide band gap. 15. The method according to claim 12, wherein the source gas contains oxygen atoms and / or nitrogen atoms. 16. The method according to claim 12, wherein the silicon-containing gas and the carbon atom-containing gas are mixed at a distance of 5 m or less from a deposition chamber. 17. The photovoltaic device according to claim 1, a storage battery for storing power supplied from the photovoltaic device and supplying power to an external load, and A power generation system comprising: a control system that monitors voltage and / or current of the electromotive element and controls power supplied from the photovoltaic element to the storage battery and / or the external load.