JP2785885B2 - Photovoltaic element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photovoltaic device, and more particularly to a non-single-crystal semiconductor material containing silicon atoms, such as hydrogenated amorphous silicon, hydrogenated amorphous silicon germanium, and hydrogenated amorphous. A photovoltaic element made of silicon carbide, microcrystalline silicon or polycrystalline silicon, etc.
In particular, the present invention relates to a photovoltaic device having a light reflecting layer. The photovoltaic device of the present invention is suitably applied to, for example, a solar cell, a sensor, an imaging device, and the like.

[0002]

2. Description of the Related Art Many studies have been made on photovoltaic elements from the viewpoint of the material and surface properties of a light reflecting layer.

For example, from the viewpoint of application to solar cells, hydrogenated amorphous silicon semiconductor (a-Si: H) and metal (Ag, Al, Au, Cu, Cr, Fe, Mo, Ni)
(A, Mada)
n, M. P. Shaw, The physics an
d Applications of Amorpho
us Semiconductors, Academi
c Press, 1988). In addition, the reflectance and texture structure of a light reflecting layer composed of silver atoms are studied (for example, “Light confinement effect in a-SiGe solar cell on 29p-MF-2 stainless steel substrate”, Autumn 1990, 51st edition) Proceedings of the Japan Society of Applied Physics Academic Lectures 2nd volume; "a-SiC / a-Si / a-SiG
e MULTI-BANDGAP STACKED S
OLAR CELLS WITHBANDGAP PR
OFILING ", Technical Digest
of the International PVSE
C-5, Kyoto, Japan, 1990, P-IA
-15).

Further, texture substrates such as Al, SUS / Al / polymer, and Ti / Ag / Ti / Al have been studied (M. HIRASAKA et.a.
l. , "DESIGN OF TEXTURED AL
ELECTRODE FORA HYDROGENA
TED AHORPHOUS SILLIC ONSO
LAR CELL ", in Solar Energy
Materials, (1990) 99-110, N.
orth-Holland).

[0005]

The above-described conventional photovoltaic element has excellent photoelectric conversion characteristics.
At present, little consideration has been given from the viewpoints of the use environment, durability characteristics, and the like. Therefore, from a practical point of view, there is a strong demand for a photovoltaic device having excellent durability and further higher characteristics.

[0006] In view of the above circumstances, an object of the present invention is to provide a photovoltaic element capable of maintaining high initial characteristics for a long period of time even in a severe environment.

Another object of the present invention is to provide a photovoltaic element which can be mass-produced at a high yield.

[0008]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the conventional problems and achieve the object of the present invention. S
It has been found that a light reflection layer containing an i atom as a main constituent element and containing an oxygen atom, a nitrogen atom, a carbon atom or an alkali metal atom is suitable.

That is, the photovoltaic device of the present invention comprises a light reflecting layer, a light reflection increasing layer, an n-type layer, a p-type layer and a p-type layer made of a non-single-crystal semiconductor material containing at least silicon atoms on a conductive substrate. In a photovoltaic element formed by stacking a mold layer and a transparent electrode, the light reflection layer has Al and Si atoms as main constituent elements, and at least one of oxygen, nitrogen, carbon or alkali metal atoms. It is characterized by containing one.

[0010]

The light reflecting layer of the photovoltaic device according to the present invention comprises Al and S
It contains i atom as a main constituent element and contains at least one of an oxygen atom, a nitrogen atom, a carbon atom and an alkali metal atom. With this structure, the characteristics of the photovoltaic device are remarkably improved.

In the photovoltaic device of the present invention, AlSi
By including oxygen atoms in the light reflecting layer of the alloy,
It is believed that the strain in the alloy is widely dispersed. That is, Al
Lattice constant (4.05 °) and the lattice constant of Si (5.4
3Å), the lattice constant of aluminum oxide (5.
12-7.9 °) and the lattice constant of silicon oxide (4.9-
It is believed that the strain in the alloy is concentrated near the oxygen atoms, and as a result, the strain is widely dispersed.

Although the details of the cause are unknown, Al and S
By including oxygen atoms in the alloy i, the crystal grain size becomes substantially uniform.

As described above, by adding oxygen to the AlSi alloy, the strain in the alloy is dispersed, and the crystal grain size becomes almost uniform. Adhesion with the increasing layer is improved, and the metal of the light reflecting layer can be prevented from diffusing into the light reflection increasing layer and the semiconductor layer.

In the photovoltaic device of the present invention, AlSi
It is considered that the strain in the alloy can be widely dispersed also by including the carbon atoms in the light reflecting layer. That is, among the Al-Si alloys, those having a small amount of solid solution of Si used in the present invention have almost the same structure as that of a single Al metal and have the same face-centered cubic lattice. It is considered that they are randomly arranged in this lattice. Here, the shortest interatomic distance of carbon (1.54 °) in the simple substance state is the shortest interatomic distance of Al (2.86 °).
And the shortest interatomic distance of Si and Si (2.35 °), it is considered that the strain of the alloy is concentrated near the carbon atoms, and as a result, the strain is widely dispersed. Seem.

Although the cause is not well understood, the inclusion of carbon atoms in the alloy of Al and Si makes the crystal grain size almost uniform.

As described above, by adding carbon to the AlSi alloy, the strain in the alloy is dispersed, and the crystal grain size becomes almost uniform. Adhesion with the increasing layer is improved, and the metal of the light reflecting layer can be prevented from diffusing into the light reflection increasing layer and the semiconductor layer.

In the photovoltaic device of the present invention, AlSi
The light reflecting layer made of an alloy contains nitrogen atoms.

When nitrogen atoms are mixed during the production of the thin film of the light reflection layer, the nitrogen atoms are taken into the thin film so as to be distributed mainly in the grain boundaries to generate a compressive stress.
It is considered that the tensile stress remaining in the light reflection layer of the Si alloy is reduced.

Although the cause is still unknown, A
The inclusion of nitrogen atoms in the lSi alloy makes the crystal grain size substantially uniform.

As described above, by adding nitrogen to AlSi, the stress in the alloy is reduced, and the crystal grain size becomes almost uniform. Adhesion with the layer is improved, and diffusion of the metal of the light reflection layer into the light reflection increasing layer and the semiconductor layer can be prevented.

Further, by containing not only one kind of nitrogen atom, carbon atom and oxygen atom but also two or more kinds thereof, the above-mentioned effect is increased and the function as a light reflecting layer is further improved.

The light reflecting layer of the photovoltaic element of the present invention is made of Al
Alkali metal (Li, Na, K, R
b, Cs).

Al-Si alloys may be made of alkali metals, especially N
Addition of a results in a surface-treated state, and the size of each crystal grain becomes very small.

Although the cause is still unknown, A
By including an alkali metal atom in the lSi alloy, the crystal grain size becomes substantially uniform.

As described above, by adding an alkali metal atom to an AlSi alloy, the size of crystal grains in the alloy is reduced, the surface condition of the alloy is improved, and the crystal grain size becomes substantially uniform. Thereby, the adhesion of the light reflection layer to the substrate and the reflection increasing layer, which is an effect of the present invention, is improved, and it is possible to prevent metal of the light reflection layer from diffusing into the light reflection increasing layer and the semiconductor layer. is there.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1, FIG. 2 and FIG. 3 are conceptual diagrams schematically showing a configuration example of a photovoltaic element of the present invention.

The photovoltaic element shown in FIG. 1 has Al and Si atoms as main constituent elements and contains at least one of oxygen, nitrogen, carbon and alkali metal atoms on an opaque conductive substrate 101. Light reflecting layer 102, reflection increasing layer 103, n-type (or p-type) non-single-crystal silicon-based semiconductor layer 104, i-type (substantially intrinsic) non-single-crystal silicon-based semiconductor layer 105, p-type (or n-type)
Non-single-crystal silicon-based semiconductor layer 106, transparent electrode 10
7, a collecting electrode 108. Light 109 is applied to the photovoltaic element from the transparent electrode 107 side.

The photovoltaic element shown in FIG. 2 is an example of a tandem structure, in which a current collecting electrode 208, a transparent electrode 207, and a p-type (or n-type) non-single-crystal silicon-based semiconductor layer 206b are formed on a transparent substrate 201. , I-type (substantially intrinsic)
Non-single-crystal silicon-based semiconductor layer 205b, n-type (or p-type) non-single-crystal silicon-based semiconductor layer 204b, p-type (or n-type) non-single-crystal silicon-based semiconductor layer 206
a, i-type (substantially intrinsic) non-single-crystal silicon-based semiconductor layer 205a, n-type (or p-type) non-single-crystal silicon-based semiconductor layer 204a, reflection enhancement layer 203,
Al and Si atoms are the main constituent elements, and at least one of oxygen atoms, nitrogen atoms, carbon atoms or alkali metal atoms
And a conductive layer (or / and a protective layer) 210.

Although not shown, the pin unit is 3
A triple-layered photovoltaic element is also a suitable photovoltaic element of the present invention.

The photovoltaic element shown in FIG. 3 is an example of a tandem cell having a texture structure. On a opaque conductive substrate 301, Al and Si atoms are mainly composed of a texture structure, and oxygen atoms and nitrogen atoms are arranged. Light reflecting layer 3 containing at least one of carbon atoms or alkali metal atoms
02, a reflection increasing layer 303, an n-type (or p-type) non-single-crystal silicon-based semiconductor layer 304a, an i-type (substantially int
rinsic) non-single-crystal silicon-based semiconductor layer 305
a, p-type (or n-type) non-single-crystal silicon-based semiconductor layer 306a, n-type (or p-type) non-single-crystal silicon-based semiconductor layer 304b, i-type (substantially intrinsic)
305b, a p-type (or n-type) non-single-crystal silicon-based semiconductor layer 306b, a transparent electrode 307, and a current collecting electrode 308. Light 309 is applied to the photovoltaic element from the transparent electrode 307 side.

In the example of FIG. 3, the texture structure is formed by the light reflecting layer, but may be formed by the substrate 301, the reflection increasing layer 303 and the like.

Hereinafter, the components of the photovoltaic device of the present invention will be described in detail.

Light Reflecting Layer In the photovoltaic device of the present invention, the light reflecting layer is a layer having an important function that affects the environment resistance and durability of the photovoltaic device. The light reflecting layer suitable for the photovoltaic device of the present invention comprises Al and Si atoms as main constituent elements and at least one of oxygen atoms, nitrogen atoms, carbon atoms or alkali metal atoms.
And the preferred content of oxygen atoms, nitrogen atoms or carbon atoms is 0.1 to 1000 ppm. When the content is 0.1 to 1000 ppm, the photoelectric conversion characteristics, the durability of the element, and the environmental resistance are further improved. Also,
The preferred content of the alkali metal atom is 2 to 100 pp.
m, and within this range, the durability and environmental resistance of the element are further improved.

As a deposition method suitable for the light reflecting layer of the photovoltaic element of the present invention, a sputtering method, a vacuum deposition method, and the like can be mentioned.

The suitable content of Si in the AlSi alloy suitable for the light reflecting layer of the photovoltaic device of the present invention is 1 to 30%, and 3 to 10% is the optimum range.

FIG. 4 is a schematic view showing an example of a DC magnetron sputtering apparatus suitable for depositing a light reflecting layer of the photovoltaic device of the present invention. The apparatus includes a deposition chamber 401, a substrate 402, a heater 403, a target 404, an insulating support 405, a DC power supply 406, a shutter 407, a vacuum gauge 408, a conductance valve 409, gas introduction valves 410, 412, 414, 416, It is composed of mass flow controllers 411, 413, 415, 417 and the like. When the light reflecting layer is deposited by the DC magnetron sputtering apparatus, oxygen atoms, nitrogen atoms, carbon atoms or alkali metal atoms (Li, Na, K, R
A target of AlSi to which a predetermined amount of (b, Cs) is added is prepared and set on the target 404 of the deposition chamber 401, and the substrate on which the light reflection layer is to be deposited is set on the substrate 402.

The content of oxygen, nitrogen or carbon atoms contained in the AlSi target is 0.1 to 150.
0 ppm is mentioned as a preferable range. The content of the alkali metal atom is preferably in the range of 2 to 100 ppm. Then, the deposition chamber 401 is evacuated to 5 × 10 ⁻⁵ Torr or less through a conductance valve 409 by an exhaust system (not shown) including an oil diffusion pump and a rotary pump. Further, the temperature of the substrate 402 is
It is preferable to set the temperature in a range from room temperature to 400 ° C.

At the time of substrate heating, it is preferable to purge the inside of the deposition chamber 401 by flowing a gas which does not easily react with the AlSi target, such as hydrogen, helium, neon, argon, and krypton, into the deposition chamber 401. As an inert gas for sputtering, for example, helium, neon, argon,
Krypton and the like are introduced, the introduction pressure into the deposition chamber 401 is 5 × 10 ⁻⁴ to 10 ⁻² Torr, and the introduction amount is 1 to
200 sccm is preferred.

When an AlSi target containing oxygen, nitrogen, carbon or alkali metal atoms is used, the DC voltage is preferably from 10 to 500 V, and the deposition rate of the light reflecting layer is preferably from 0.1 to 100 ° / sec. .

Similarly, an RF sputtering method can be used instead of the DC magnetron sputtering method. In the case of the RF sputtering method, D
An RF power source is used instead of the C power source.
A frequency near 3.56 MHz is a preferred frequency. The RF power supplied from the RF power source to the deposition chamber 401 is preferably 0.01 to 10 W / cm ² .

Next, when the light reflecting layer is deposited by the reactive sputtering method, the AlSi target containing oxygen, nitrogen or oxygen is replaced with an AlSi target containing little or no oxygen, nitrogen or carbon. Further, the light reflection layer can be deposited by using the inert gas to which an oxygen-containing gas, a nitrogen-containing gas, or a carbon-containing gas is added instead of the inert gas as a sputtering gas. In the case of the reactive sputtering method, the addition amount of oxygen atoms, nitrogen atoms or carbon atoms in the inert gas is preferably 1 to 2000 ppm.

FIG. 8 shows a sputtering apparatus capable of continuously depositing the light reflection layer and the light reflection increasing layer without breaking the vacuum in the deposition chamber. The apparatus includes a deposition chamber 801, a substrate 802, a heater 803, a target 804 for depositing a light reflecting layer,
It is composed of a target 818 for depositing a light reflection increasing layer. The deposition conditions for the light reflecting layer are the same as the deposition conditions for the deposition apparatus shown in FIG.

FIG. 9 shows a light reflecting layer deposition apparatus (vacuum deposition apparatus) using a vacuum deposition method. The vacuum evaporation apparatus includes a deposition chamber 901, a substrate 902, a heater 903, an evaporation source 90
4. Electron beam (EB) gun 905, high voltage power supply 90
6, shutter 907, vacuum gauge 908, conductance valve 909, gas introduction valves 910, 912, 91
4,916 Mass flow controller 911, 913, 9
15, 917 and an exhaust device (not shown). When depositing a light reflection layer with this vacuum deposition apparatus, the substrate is set in a deposition chamber, and an oxygen atom, a nitrogen atom, a carbon atom or an alkali metal atom-containing Al atom is contained as a deposition source.
Set Si. The preferred content of oxygen atoms, nitrogen atoms or carbon atoms contained in AlSi of the evaporation source is 1 to
2000 ppm. The preferable content of the alkali metal atom is 2 to 200 ppm. Then, the deposition chamber is evacuated to 5 × 10 ⁻⁵ Torr or less, and the substrate temperature is set between room temperature and 400 ° C. When the substrate temperature reaches a predetermined temperature, an electron beam is emitted from the EB gun to the evaporation source. The pressure in the deposition chamber during vapor deposition is 1 × 10 ^{−5 to} 5 × 10
^-4 Torr is preferable, and the deposition rate of the light reflecting layer is preferably 0.1 to 100 ° / sec.

When the light reflecting layer is deposited by reactive deposition, AlSi having a small or no content of the above-mentioned atoms is used as a deposition source in place of the above-mentioned AlSi containing oxygen, nitrogen or carbon atoms. , An oxygen atom-containing gas, a nitrogen-containing gas or a carbon-containing gas in an amount of 1 × 10 ^-4 to
5 × 10 ⁻³ Torr is introduced. The light reflecting layer can be formed by electron beam evaporation of the AlSi atoms under such a pressure.

FIG. 12 shows an apparatus in which a method of depositing a light reflection layer by an electron beam evaporation method and a method of depositing an increase in light reflection by a sputtering method are incorporated in the same deposition apparatus. The deposition conditions for the light reflecting layer are the same as the deposition conditions using the electron beam evaporation apparatus shown in FIG.

When a light reflecting layer containing oxygen, carbon and nitrogen atoms is deposited by reactive sputtering or reactive vapor deposition, the source gas for introducing oxygen, carbon and nitrogen atoms is , For example, O ₂ , C
H ₄ and N ₂ are used.

In order to form a light reflecting layer mainly composed of AlSi containing oxygen, nitrogen, carbon or alkali metal atoms into a textured structure, for example, the substrate temperature is set relatively high (300 ° C. or higher). Obtained by deposition.

The AlSi crystal grain size of the light reflecting layer suitable for the photovoltaic device of the present invention is in a range of 100 ° to 10 μm, and an optimum range of 500 ° to 2 μm. The thickness of the light reflecting layer suitable for the photovoltaic device of the present invention is 5
00 ° to 3 μm.

Reflection Increasing Layer In the photovoltaic device of the present invention, the light reflection increasing layer is an important layer that comes into contact with the light reflecting layer and is closely related to the characteristics of the photovoltaic device. For example, ZnO, SnO ₂ , In ₂ O ₃ , IT
O, TiO ₂ , CdO, Cd ₂ SnO ₄ , Bi ₂ O ₃ ,
MoO ₃ , Na _X WO ₃ (x = 2 to 3) and the like are preferably used.

As a method for depositing the reflection increasing layer, for example, a vacuum deposition method, a sputtering method, a CVD method, a spray method,
Suitable methods include a spin-on method and a dipping method.

The optimum layer thickness varies depending on the refractive index.
10 μm.

When a texture structure is to be formed with the light reflection increasing layer, the substrate temperature at the time of depositing the light reflection increasing layer is set to 300.
It can be formed by setting the temperature higher than ℃ and depositing it to a thickness of 2 μm or more.

P-type layer or n-type layer In the photovoltaic device of the present invention, the p-type layer or the n-type layer is an important layer that affects the characteristics of the photovoltaic device.

The amorphous material (denoted by a-) and the microcrystalline material (μc-) of the p-type layer or the n-type layer of the photovoltaic device of the present invention.
) Or a polycrystalline material (denoted as "poly-"), a p-type valence electron control agent (Group III atom B, Al, Ga, In, Tl) or an n-type valence electron Materials to which a control agent (group V atom P, As, Sb, Bi in the periodic table) is added at a high concentration can be given.

As the amorphous material, for example, a-Si:
H, a-Si: HX, a-SiC: H, a-SiC: H
X, a-SiGe: H, a-SiGeC: H, a-Si
O: H, a-Sin: H, a-SiON: HX, a-S
iOCN: HX, μc-Si: H, and microcrystalline materials include, for example, μc-SiC: H, μc-Si: HX, μc
—SiC: HX, μc-SiGe: H, μc-SiO:
H, μc-SiGeC: H, μc-SiN: H, μc −
SiON: HX, μc-SiOCN: HX,), and polycrystalline materials include, for example, poly-Si: H, poly-
Si: HX, poly-SiC: H, poly-Si
C: HX, poly-SiGe: H, poly-Si,
Poly-SiC, poly-SiGe and the like can be mentioned. Here, X is a halogen atom.

In particular, the p-type layer or the n-type layer on the light incident side includes:
An amorphous semiconductor layer having a wide band gap is suitable as a crystalline semiconductor layer with low light absorption.

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 set to 0.3.
An appropriate amount is 1 to 50 at%.

A hydrogen atom (H, D) or a halogen atom X contained in the p-type layer or the n-type layer is
It functions to compensate for dangling bonds of the type layer and to improve the doping efficiency of the p-type layer or the n-type layer. The appropriate amount of hydrogen atoms or halogen atoms added to the p-type layer or the n-type layer is 0.1 to 40 at%. In particular, a p-type layer or n
When the mold layer is crystalline, the preferred content of hydrogen atoms or halogen atoms is 0.1 to 8 at%.

Further, it is preferable that a large amount of hydrogen atoms and / or halogen atoms be distributed on each interface side of the p-type layer / i-type layer and the n-type layer / i-type layer. The preferred content of atoms and / or halogen atoms is 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.

Further, a transparent electrode / p-type layer or a transparent electrode /
A preferred distribution form includes a large distribution of hydrogen atoms and / or halogen atoms at each interface side of the n-type layer, and the content of hydrogen atoms and / or halogen atoms near the interface is bulk. The content is preferably 1.1 to 2 times the content. By increasing the content of hydrogen atoms or halogen atoms near each interface between the transparent electrode / p-type layer and the transparent electrode / n-type layer, the defect levels and mechanical strain near the interface can be 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 device of the present invention are preferably those having an activation energy of 0.2 eV or less, more preferably 0.1 eV or less. The specific resistance is preferably 100 Ωcm or less,
It is more preferably 1 Ωcm or less. Further, the thickness of the p-type layer and the n-type layer is preferably from 10 to 500 °, more preferably from 30 to 100 °.

As the source gas suitable for depositing the p-type layer or the n-type layer of the photovoltaic device of the present invention, for example, a gasizable compound containing a silicon atom, a gasizable compound containing a germanium atom, nitrogen Examples thereof include a gasizable compound containing an atom and a mixed gas of the compound.

Specific examples of the gasizable compounds containing silicon atoms include SiH ₄ , SiH ₆ , and SiH ₄ .
_{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, SiFD ₃ , SiF ₂ D ₂ , SiD ₃ H, Si ₂ D
₃ H _{3 and the} like. Examples of the gasifiable compound containing a germanium atom include, for example, GeH ₄ , G
eD ₄ , GeF ₄ , GeFH ₃ , GeF ₂ H ₂ , GeF
₃ H, GeHD ₃ , GeH ₂ D ₂ , GeH ₃ D, Ge ₂
H ₆ and Ge ₂ D ₆ are exemplified. 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 can be mentioned. Examples of the nitrogen-containing gas include N ₂ , NH ₃ , ND ₃ , N
O, NO ₂ and N ₂ O are mentioned. Examples of the oxygen-containing gas include O ₂ , CO, CO ₂ , NO, NO ₂ , N
₂ O, CH ₃ CH ₂ , OH, CH ₃ OH and the like.

In the present invention, the substance introduced into the p-type layer or the n-type layer for controlling the valence electrons may be any of the materials listed in Periodic Table I.
Group II and Group V atoms are included. Examples of useful starting materials for introducing Group III atoms include, for example, 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
Borohydride such as ₆ H _14, it can be mentioned BF _3, BCl ₃ or the like boron halide or the like. In addition, AlC
Examples include l ₃ , GaCl ₃ , InCl ₃ , and TlCl _3, but B ₂ H ₆ and BF ₃ are particularly suitable.
In addition, for example, PH ₃ , P ₂ H is used effectively as a starting material for introducing a group V atom for introducing a phosphorus atom.
Phosphorus hydride such as 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 ,
AsCl ₃ , AsBr ₃ , AsF ₅ , SbH ₃ , SbF
_{3, SbF 5, SbCl 3,} SbCl 5, BiH 3, B
iCl ₃ , BiBr _{3 and the} like can also be mentioned. Of these, PH ₃ and PF ₃ are particularly suitable.

The p-type layer or the n-type layer is deposited by RF plasma CVD or μW plasma CVD. Especially R
When deposition is performed by the F plasma CVD method, 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 is 100 to 350 ° C., the internal pressure is 0.1 to 10 Torr, and the RF power is 0.05.
１．０1.0 W / cm ² , deposition rate is 0.1０．１30 / s
ec and the like are preferable conditions.

The compound capable of being gasified is 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. In particular, microcrystalline semiconductors and a-Si
In the case of depositing a wide band gap layer such as C: H having a small light absorption, it is preferable to dilute the source gas by a factor of 2 to 100 with hydrogen gas and introduce the RF gas at a relatively high power. An appropriate RF frequency is 1 to 100 MHz, and a frequency near 13.56 MHz is particularly preferable.

When a p-type layer or an n-type layer is deposited by the μW plasma CVD method, the μW plasma CVD apparatus
A method in which microwaves are introduced into the deposition chamber through a waveguide through a dielectric window (such as alumina ceramics) is suitable. When a p-type layer or an n-type layer is deposited by the μW plasma CVD method, the substrate temperature in the deposition chamber is 100 to 400 ° C., the internal pressure is 0.5 to 30 mTorr, and the μW power is 0.01 to 1 W.
/ Cm ³ , μW is preferably 0.5 to 10 GHz.

At this time, the compound capable of being gasified is H ₂ ,
The gas may be appropriately diluted with a gas such as He, Ne, Ar, Xe, or Kr and introduced into the deposition chamber. In particular, microcrystalline semiconductors and a-Si
When depositing a layer having a small light absorption or a wide band gap such as C: H, it is preferable to dilute the source gas 2 to 100 times with hydrogen gas and to introduce a relatively high power of μW.

I-Type Layer In the photovoltaic device of the present invention, the i-type layer is an important layer that generates and transports carriers with respect to irradiation light.

As the i-type layer of the photovoltaic device of the present invention,
It may be slightly p-type and slightly n-type. When a semiconductor layer in which the product of the hole mobility and the lifetime is smaller than the product of the electron mobility and the lifetime is used as the i-type layer, a slightly p-type layer is suitable. In the opposite case, that is, when a semiconductor layer in which the product of electron mobility and lifetime is smaller than the product of hole mobility and lifetime is used, a slightly n-type layer is suitable.

As the i-type layer, for example, a-Si: H, a
-Si: HX, a-SiC: H, a-SiC: HX, a
-SiGe: H, a-SiGe: HX, a-SiGe
C: An amorphous material such as HX is exemplified. In particular, as the i-type layer, a material which is intrinsically formed by adding a group III atom and / or a group V atom of the periodic table as a valence control agent to the amorphous material is preferable. Are listed.

The hydrogen atoms (H, D) or the halogen atoms (X) contained in the i-type layer work to compensate for the dangling bonds of the i-type layer, and the mobility and lifetime of carriers in the i-type layer. To improve the product of In addition, these atoms form a p-type layer /
It works to compensate for the interface state of each interface of the i-type layer and the n-type layer / i-type layer, and has the effect of improving the photovoltaic power, photocurrent and photoresponsiveness of the photovoltaic element. The preferred content of hydrogen atoms and / or halogen atoms in the i-type layer is 1 to 40 at.
%. In particular, on each interface side of the p-type layer / i-type layer and the n-type layer / i-type layer, those having a large distribution of the content of hydrogen atoms and / or halogen atoms are mentioned as a preferable distribution form. The content of hydrogen atoms and / or halogen atoms in the vicinity is preferably 1.1 to 2 times the content in the bulk.

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.

To achieve the object of the present invention effectively,
Basic physical properties of the i-type layer include, for example, electron mobility of 0.01 cm ² / V / sec or more and hole mobility of 0.1 cm ² / V / sec.
0001 cm ² V / sec or more, band gap is 1.
1 to 2.2 eV, localization density at the center of the forbidden zone is 10 ¹⁸ / cm
³ / eV or less, and the inclination of the Urbach tail on the valence band side is preferably 65 meV or less. Furthermore, the current-voltage characteristics of the photovoltaic device of the present invention were measured at AM 1.5 and 100 mW / cm ² , and curve fitting was performed by the Hecht equation. The product of the mobility and the life obtained from the curve fitting was 10 ^−1. Desirably, it is ⁰ cm ² / V or more.

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.

The source gas suitable for depositing the i-type layer of the photovoltaic device of the present invention includes a gasizable compound containing a silicon atom, a gasizable compound containing a germanium atom, and a gas containing a carbon atom. Compounds that can be
And a mixed gas of the compounds.

Specific examples of the gasizable compound containing silicon atoms include SiH ₄ , SiH ₆ , and SiH ₄ .
_{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, SiFD ₃ , SiF ₂ D ₂ , SiD ₃ H, Si ₂ D
₃ H _{3 and the} like. Examples of the gasifiable compound containing a germanium atom include, for example, GeH ₄ , G
eD ₄ , GeF ₄ , GeFH ₃ , GeF ₂ H ₂ , GeF
₃ H, GeHD ₃ , GeH ₂ D ₂ , GeH ₃ D, Ge ₂
H ₆ and Ge ₂ D ₆ are exemplified. 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 and the} like.

In the present invention, the valence electrons of the i-type layer are controlled.
The substance to be introduced into the i-type layer for the
Group atoms and group V atoms. Group III atom conduction
Some of the useful starting materials to use include:
Specifically, for boron atom introduction, B_TwoH₆, B_Four
H_Ten, B_FiveH₉, B_FiveH₁₁, B₆H_Ten, B₆H₁₂, B₆ H
₁₄Borohydride, BF_Three, BCl_ThreeHalogenation
Boron and the like can be mentioned. In addition, AlC
l_Three, GaCl_Three, InCl_Three, TlCl_ThreeAlso use
be able to. In addition, as a starting material for introducing a group V atom,
What is effectively used is, for example, for introducing a phosphorus atom.
PH_Three, P_TwoH_FourPhosphorus hydride, PH_FourI, PF_Three, P
F_Five, PCl_Three, PCl_Five, PBr_ThreePBr_Five, PI_Three
And the like. In addition, AsH_Three, A
sF_Three, AsCl_Three, AsBr_Three, AsF_Five, Sb
H_Three, SbF_Three, SbF_Five, SbCl_Three, SbCl_Five,
BiH_Three, BiCl_Three, BiBr_ThreeAnd so on.
Wear.

The amount of Group III and Group V atoms introduced into the i-type layer for controlling the conductivity type is 1
It is preferably at most 000 ppm.

Examples of the method for depositing an i-type layer suitable for the present invention include an RF plasma CVD method and a μW plasma CVD method. In the case of the RF plasma CVD method, a capacitively coupled RF plasma CVD method is particularly suitable.

When an i-type layer is deposited by the RF plasma CVD method, the substrate temperature is 100 to 350 ° C., and the internal pressure is 0.
1 to 10 Torr, RF power is 0.05 to 1.0 W
/ Cm ² , and a deposition rate of 0.1 to 30 ° / sec are preferably used.

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. In particular, when depositing a layer having a wide band gap such as a-SiC: H, it is preferable to use hydrogen gas at 2-1 to 1: 1.
It is preferable to dilute the source gas by a factor of 00 and to introduce a relatively high RF power. RF frequency is 1
MHz to 100 MHz is a suitable range, particularly 13.
A frequency near 56 MHz is preferred.

In the case where the i-type layer is deposited by the μW plasma CVD method, a method of introducing microwaves into the deposition chamber through a waveguide through a dielectric window (alumina ceramics or the like) is suitable. The substrate temperature in the deposition chamber is 100 to 400 ° C., the internal pressure is 0.5 to 30 mTorr, and the μW power is 0.01 to 1 W
/ Cm ³ , μW is preferably 0.5 to 10 GHz. Further, when a bias rod (plate-like or ring-like) may be provided in the plasma to control the plasma potential, the characteristics are further improved. Particularly in a region where the deposition rate is not saturated with respect to the introduced μW power, the control of the plasma potential by the bias rod works effectively. At this time, it is most effective to make the bias rod positive with respect to the potential of the substrate. When the bias applied to the bias rod is a DC bias, the voltage is preferably 10 to 500 V. When the bias is an AC bias, the voltage between the maximum and minimum applied voltages is 10 to 500 V.
Is preferred. Further, when applying an RF bias to the bias rod, the RF power is preferably 10 W to 3 KW. RF
In the case of Baice, the characteristics are improved especially when RF power is introduced above the μW power. In both cases of the AC bias and the RF bias, it is preferable that the substrate has a negative potential with respect to the bias rod as in the case of the DC bias.

The reason why the characteristics of the deposited film are improved by the bias is considered that positive ions play an important role in the μW plasma CVD method. Further, it is considered that the combination of the active species and the ionic species in the plasma is important because the characteristics are improved in a unique combination of the μW power and the bias.

The compound capable of being gasified is 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. In particular, when a layer having a wide band gap such as a-SiC: H is deposited, 2 to 10
It is preferable to dilute the source gas by a factor of 0 and to introduce a relatively high μW power.

FIGS. 13 and 14 show a .mu.W plasma CVD apparatus suitable for depositing a p-type layer, an n-type layer and an i-type layer according to the present invention and an R-type plasma CVD apparatus.
FIG. 2 is a schematic explanatory view of an F plasma CVD apparatus.

The μW plasma CVD apparatus shown in FIG. 13 has a deposition chamber 1301, a microwave introduction dielectric window 1302, a gas introduction pipe 1303, a substrate 1304, a heater 130
5, vacuum gauge 1306, conductance valve 1307,
Auxiliary valve 1308, leak valve 1309, waveguide 1
310, a bias power supply 1311, a bias rod 1312,
Source gas supply device 1320, mass flow controllers 1321 to 1326, gas inflow valves 1331 to 133
6, gas outflow valves 1341 to 1346, raw material gas cylinder valves 1351 to 1356, pressure regulator 1361 to
1366, raw material gas cylinders l371 to 1376 and the like.

The RF plasma CVD apparatus shown in FIG.
Deposition chamber 1401, cathode 1402, gas inlet tube 140
3, substrate 1404, heater 1405, vacuum gauge 14
06, conductance valve 1407, auxiliary valve 14
08, a leak valve 1409, an RF matching box 1412, and the like.

FIG. 1 suitable for depositing the photovoltaic device of the present invention
The deposition apparatus shown in FIG. 3 and FIG. 14 is preferably made of stainless steel or aluminum material. SUS304, SUS304N especially when made of stainless steel
2, SUS304L, SUS304LN, SUS32
Stainless steels having excellent corrosion resistance, pitting corrosion resistance, intergranular corrosion resistance, and heat resistance, such as 1, SUS347, SUS316, and SUS316L, are mentioned as the optimum materials. In addition, when manufacturing a deposition apparatus using an aluminum material, JIS 5
Al-Mg-based materials of the 000's are mentioned as the most suitable ones.

As the material of the dielectric window for introducing microwaves in the μW plasma CVD apparatus shown in FIG. 13, a material containing 95% or more of alumina ceramics (Al ₂ O ₃ ) is the most suitable.

Transparent Electrode As the transparent electrode used in the photovoltaic device of the present invention, for example, a transparent electrode such as tin oxide, indium oxide or indium-tin oxide is suitable. And / or oxide transparent electrodes containing carbon atoms are suitable.

By including a nitrogen atom in tin oxide, indium oxide and indium-tin oxide, the crystal grain size of the oxide constituting the transparent electrode is increased, and the dispersion of the crystal grain size is small. Become. Further, the distortion of the transparent electrode can be reduced. As a result, the specific resistance of the transparent electrode can be reduced, and the transmittance of the transparent electrode can be improved.

In addition, by adding nitrogen atoms to the transparent electrode, the crystal shape of the oxide constituting the transparent electrode can be made relatively smooth, and the surface properties of the transparent electrode can be improved. it can. In particular, when the transparent electrode is deposited on the semiconductor layer, the adhesion between the semiconductor layer and the transparent electrode is significantly improved. In addition, when a non-single-crystal silicon-based semiconductor layer is deposited on the transparent electrode, abnormal deposition of the non-single-crystal silicon-based semiconductor layer can be reduced.
Therefore, even if a thin p-type layer (or n-type layer) is deposited, electric leakage can be reduced. As a result, the average characteristics of the photovoltaic element are improved.

Although the details are unknown, it is considered that nitrogen atoms are involved in the crystal growth of the oxide. By introducing nitrogen atoms, a transparent electrode having good characteristics can be obtained even at a relatively low temperature.

The transparent electrode containing a nitrogen atom of the present invention is deposited as follows.

For deposition of the transparent electrode, a sputtering method and a vacuum deposition method are suitable deposition methods. For example, in a DC magnetron sputtering apparatus, when depositing a transparent electrode made of tin oxide containing a nitrogen atom on a substrate, the target is metal tin (Sn) or tin oxide (Sn).
A target containing a nitrogen atom-containing substance in O ₂ ) or the like is used.

When depositing a transparent electrode made of indium oxide containing nitrogen atoms, the target may be a metal indium (In) or a target containing indium oxide (In ₂ O ₃ ) containing a nitrogen atom-containing substance. Used. In the case of depositing a transparent electrode composed of indium-tin oxide containing nitrogen atoms, the target is metal tin, metal indium or an alloy of metal tin and metal indium, tin oxide, indium oxide, indium-tin oxide. For example, a target containing a nitrogen atom may be used in appropriate combination.

When the transparent electrode of the present invention is deposited by the reactive sputtering method, the target or / and the target which does not contain a nitrogen atom are appropriately combined as a sputtering target, and a nitrogen atom-containing source gas is used. Can be introduced into the deposition chamber, and nitrogen atoms can be introduced into the transparent electrode using plasma energy.

As a source gas containing a nitrogen atom suitable for the reactive sputtering method, for example, N ₂ , NH ₃ , N
D ₃ , NO, NO ₂ , and N ₂ O.

The content of nitrogen atoms contained in the transparent electrode of the present invention is preferably 100 ppm or less. In addition, the content of nitrogen atoms contained in the target largely depends on sputtering conditions in order to contain nitrogen atoms of 100 ppm or less in the transparent electrode.
It is 0 ppm.

In order to make the transparent electrode contain 100 ppm or less of nitrogen atoms by the reactive sputtering method, the mixing ratio of the nitrogen atom-containing gas to the sputtering gas is preferably 200 ppm or less.

When depositing the nitrogen-containing transparent electrode of the present invention by a sputtering method, the substrate temperature is an important factor, and is preferably from 25 to 600 ° C. 25-250 ° C
Even at a low temperature, a transparent electrode exhibiting excellent characteristics as compared with the prior art can be obtained. As a sputtering gas, an inert gas such as an argon gas (Ar), a neon gas (Ne), a xenon gas (Xe), and a helium gas (He) is used, and an Ar gas is particularly preferable. In addition, it is preferable to add oxygen gas (O ₂ ) to the inert gas as needed. Particularly when a metal is targeted, the oxygen gas (O ₂ ) is essential.

In the case of sputtering, the pressure in the discharge space is set to 0.1 to 50 for effective sputtering.
mTorr is preferred. As a power supply, DC power supply and RF
A power supply is suitable. A suitable range for the electric power during sputtering is 10 to 1000 W.
Further, the deposition rate depends on the pressure in the discharge space and the discharge power, and a preferable deposition rate is 0.1 to 100 ° / s.
ec.

It is preferable that the layer thickness of the transparent electrode containing a nitrogen atom of the present invention is deposited so as to satisfy the conditions of the antireflection film. The specific layer thickness is 500-3000
Å.

A second method suitable for depositing the nitrogen-containing transparent electrode of the present invention is a vacuum deposition method. As the evaporation source, a metal tin, a metal indium, or an indium-tin alloy to which the above-mentioned nitrogen atom-containing substance is added is used. The suitable content of the nitrogen atom is approximately 100 ppm or less.

The deposition conditions are as follows.
After reducing the pressure to about 600 ° C. to a pressure of 1 × 10 ⁻⁶ Torr or less, oxygen gas (O ₂ ) was added to 5 × 10 ^{−5 to} 9 × 10 ^−4.
It is introduced into the deposition chamber within the range of 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.

A transparent electrode containing a nitrogen atom by reactive vapor deposition
When depositing, the above-mentioned vapor deposition source and / or
No deposition source, nitrogen gas containing 5 × in the deposition chamber
10 ^-FourEvaporate to a transparent electric
Poles may be deposited. In addition, RF power is conducted at the vacuum level.
To generate plasma and deposit through the plasma
May be performed.

The preferable deposition rate of the transparent electrode under the above conditions is 0.1 to 100 ° / sec. When the deposition rate is less than 0.1Å / sec, the productivity is reduced, and
If it exceeds 0 ° / sec, the film becomes a coarse film, and the transmittance, the electrical conductivity and the adhesion are reduced.

By simultaneously containing carbon atoms in the nitrogen-containing transparent electrode of the present invention, the characteristics of the photovoltaic element can be further improved. That is, by simultaneously containing a nitrogen atom and a carbon atom in the transparent electrode, the resistance of the photovoltaic device to heat cycles is further improved, and the flexibility of the transparent electrode is further improved to prevent the photovoltaic device from cracking. Effect is further improved.
The preferred amount of carbon atoms added in the present invention is 10
It is 0 ppm or less.

The method for introducing carbon atoms into the transparent electrode can be carried out in the same manner as the method for introducing nitrogen atoms.

For example, carbon atoms can be contained in the transparent electrode by performing sputtering or vacuum deposition using a target or deposition source for depositing a transparent electrode or a deposition source containing carbon atoms. At this time, graphite-like carbon, diamond-like carbon, or the like is suitable as a starting material of carbon atoms to be contained in the target or the evaporation source.

When a transparent electrode containing nitrogen and carbon atoms is deposited by a reactive sputtering method, the target and / or the target not containing carbon atoms are appropriately combined, and the nitrogen target is used as a sputtering target. In addition to the contained source gas, a carbon atom-containing source gas is introduced into the deposition chamber, and the plasma energy can be used to introduce carbon atoms in addition to nitrogen atoms into the transparent electrode using plasma energy.

Examples of the carbon atom-containing source gas suitable for the reactive sputtering method include CH ₄ , CD ₄ , and 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.

When a transparent electrode containing carbon atoms in addition to nitrogen atoms is deposited by reactive vapor deposition, the above-mentioned vapor deposition source and / or the above-mentioned vapor deposition source which does not contain carbon atoms are placed in the deposition chamber by the above-mentioned carbon-containing gas. The transparent electrode may be deposited by evaporating in the state of being introduced at 10 × 10 ⁻⁴ Torr or less. In addition, RF power may be introduced at the vacuum degree to generate plasma, and vapor deposition may be performed via the plasma.

On the other hand, when forming a transparent electrode made of the oxide containing no nitrogen atom and / or carbon atom, the transparent electrode may be deposited by a conventional method.

Conductive Substrate As the conductive substrate, a conductive material may be used as it is, or a support formed of an insulating material or a conductive material and then subjected to a conductive treatment may be used. . Examples of the conductive support include NiCr, stainless steel, Al, and C.
r, Mo, Au, Nb, Ta, V, Ti, Pt, Pb,
Metals such as Sn and alloys thereof are exemplified. Examples of the electrically insulating support include synthetic resin films such as polyester, polyethylene, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, and polyamide, or sheets, glass, ceramics, and paper. Is mentioned. It is preferable that at least one surface of these electrically insulating supports is subjected to conductive treatment, and a photovoltaic layer is provided on the conductive-treated surface side.

For example, in the case of glass, for example, NiCr, Al, Cr, Mo, Ir, Nb, Ta,
V, Ti, Pt, Pb, In ₂ O ₃ , ITO (In ₂ O
₃ + Sn) to provide conductivity by providing a thin film, or a synthetic resin film such as a polyester film, for example, NiCr, Al, Ag, Pb,
Zn, Ni, Au, Cr, Mo, Ir, Nb, Ta,
A metal thin film of V, Ti, Pt or the like 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. However, when flexibility as a photovoltaic element is required, the thickness can be set within a range where the function as a support can be sufficiently exhibited. It can be as thin as possible. However, due to the manufacturing and handling of the support,
In terms of mechanical strength and the like, the thickness is usually 10 μm or more.

Conductive Layer (and Protective Layer) The conductive layer may be a conductive material, or a conductive material formed by forming an insulating material. Examples of the conductive material include NiCr, stainless steel, Al, Cr,
Mo, Au, Nb, Ta, V, Ti, Pt, Pb, Sn
And alloys thereof. The metal may be formed as a thin film by a vacuum evaporation method, a sputtering method, or the like. Examples of the electrically insulating material include films or sheets of synthetic resins such as polyester, polyethylene, polycarbonate 2, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, and polyamide, or sheets, glass, ceramics, and paper. . These electrically insulating materials are preferably applied with an adhesive on at least one surface thereof and adhered on the metal thin film layer.

The electrically insulating material can be made as thin as possible as long as the function as the protective layer is sufficiently exhibited.
However, the thickness is usually 10 μm or more in terms of production, handling, mechanical strength, and the like.

(Experimental Examples) The effects of the present invention will be described in detail with reference to the following experimental examples conducted in the course of reaching the present invention.

(Experimental Example 1-1) First, a light reflecting layer of AlSi containing oxygen atoms was formed on a stainless steel substrate by using a DC magnetron sputtering apparatus shown in FIG.

In the drawing, reference numeral 402 denotes a 50 mm square and a thickness of 0.2 m.
m, mirror-finished stainless steel (SUS43
0), with acetone (CH ₃ OCH ₃ ) for 10 minutes,
Ultrasonic cleaning was performed for 10 minutes with isopropanol (CH ₃ CHOHCH ₃ ), and hot air drying was performed at 80 ° C. for 30 minutes.

In the drawing, reference numeral 404 denotes an aluminum-silicon alloy (AlSi) target having a purity of 99.999%, which is insulated from the deposition chamber 401 by an insulating support 405. In the figure, reference numerals 410, 412, 414, and 416 denote gas introduction valves, respectively, which are not shown in the drawings. Argon (Ar) gas cylinder (purity: 99.9999%) and nitrogen (N ₂ / Ar) diluted to 50 ppm with argon (Ar) gas. ) Gas cylinder, methane (CH ₄ / Ar) gas cylinder diluted to 50 ppm with argon (Ar) gas, argon (Ar)
It is connected to an oxygen (O ₂ / Ar) gas cylinder diluted to 50 ppm with gas.

First, the inside of the deposition chamber 401 is evacuated by a vacuum pump (not shown), and the reading of the vacuum gauge 408 is about 1 × 10 ⁻⁶ T.
orr, the gas introduction valves 410, 416
Is gradually opened so that the O ₂ / Ar gas flow rate is ₂ sccm and A
The mass flow controllers 411 and 417 adjust the flow rate of the r gas to 10 sccm, and
01 and a vacuum gauge 40
While watching 8, conductance valve (pattern fly type) 4
09 opening was adjusted. Thereafter, the voltage of the DC power supply 406 was set to -400 V, DC power was introduced to the target 404, and a DC glow discharge was generated. After a lapse of 5 minutes, the shutter 407 is opened and the AlS
Production of the light reflection layer of i was started. When a light reflection layer having a thickness of 450 nm was produced, the shutter 407 was closed, the output of the DC power supply 406 was turned off, and the DC glow discharge was stopped. Next, the gas introduction valve 416 is closed to stop the flow of the O ₂ / Ar gas into the deposition chamber 401, and the flow rate of the Ar gas becomes
Mass flow controller 411 so as to be 0 sccm
Was adjusted.

Next, the conductance valve 409 is closed, the deposition chamber 401 is gradually leaked, and A containing oxygen atoms is leaked.
The fabrication of the 1Si light reflecting layer was completed.

(Experimental Example 1-2) In Experimental Example 1-1,
Instead of oxygen gas diluted with Ar gas, 5
Experimental Example 1 was used except that CH ₄ gas diluted to 0 ppm was used.
In the same manner as in Example 1, an AlSi light reflecting layer containing carbon atoms was produced.

(Experimental example 1-3) In Experimental example 1-1,
Instead of oxygen gas diluted with Ar gas, 5
Using N ₂ gas diluted to 0 ppm, other Examples 1-1
In the same manner as in the above, an AlSi light reflecting layer containing a nitrogen atom was produced.

(Experimental example 1-4) In Experimental example 1-1,
Alkali metal atoms (Li, Na, K,
Rb, Cs) using an aluminum-silicon alloy (AlSi) to which 20 ppm has been added,
An AlSi light reflecting layer containing any of alkali metal atoms (Li, Na, K, Rb, Cs) was prepared in the same manner as in Experimental Example 1-1 except that the flow rate was 0 sccm.

(Comparative Experimental Example 1) An AlSi light reflective layer was produced in the same manner as in Experimental Example 1-1 except that no O ₂ gas was flowed into the deposition chamber 401 during the production of the light reflective layer.

In the DC magnetron sputtering apparatus shown in FIG. 4, first, an Ar gas flow rate of 35 sccm was introduced into the deposition chamber 401 and the pressure in the deposition chamber 401 was reduced to 6 mT.
Adjusted to orr. Thereafter, the voltage of the DC power supply 406 is
At a setting of 400 V, DC power was introduced into the target 404 to generate a DC glow discharge. Next, the shutter 407 is opened to start manufacturing a light reflecting layer of AlSi on the substrate 402. When the light reflecting layer having a thickness of 450 nm is formed, the shutter 407 is closed, and the output of the DC power supply 406 is turned off. Discharge was stopped. Next, the flow rate of Ar gas was set to 100 sccm, and the conductance valve 409 was set.
Was closed, the deposition chamber 401 was gradually leaked, and the fabrication of the aluminum-silicon alloy light reflecting layer of the conventional photovoltaic element was completed.

The following four evaluation tests were performed on the light reflecting layer manufactured as described above in order to demonstrate the effect of the present invention.

(Evaluation a) Variation in crystal grain size (Evaluation b) Adhesion (Evaluation c) Temperature dependence of crystal grain size (Evaluation d) Adhesion in laminated structure The crystal grain size of AlSi in the light reflection layer In order to examine the variation, a Hitachi scanning electron microscope (SEM) S-
The surface was observed using 530, and the area was 100 μm × 1
The grain size of all crystals within the 00 μm square was measured.
The particle size distribution of the sample is as shown in FIG.
It was found that the dispersion of the crystal grain size was much smaller in Examples 1-4 than in Comparative Experimental Example 1. Experimental Example 1
Almost no difference was observed between samples 1-4.

(Evaluation b) Adhesion In order to check the adhesion of the light reflection layer, a stainless steel substrate 60 on which the light reflection layer was formed using a bending tester as shown in FIG.
No. 1 bending test was performed. In the figure, first, the surface 601a on which the light reflecting layer is formed is turned rightward, and the end of the stainless steel substrate 601 is firmly fixed so as to slightly contact the tip of the bending rod 602. Next, compressed air was introduced into the air cylinder 603, and the pressure of the compressed air was adjusted so that the extrusion speed of the bending rod was about 1 m / s, the retraction speed was about 1 m / s, and the stroke was 3.0 cm. The bending test was performed 10,000 times in a normal atmosphere, and the area of the peeled light reflecting layer was calculated using a normal optical microscope. (B) Further, a similar bending test was performed with the surface 601a on which the light reflecting layer was formed facing left. Table 1 shows the results
Shown in

As is clear from Table 1, Experimental Examples 1-1 to 1-1
It can be seen that the light reflecting layer of 1-4 has significantly improved adhesion as compared with Comparative Example 1.

(Evaluation c) Temperature Dependence of Crystal Grain Size In order to examine the relationship between the growth of AlSi crystals in the light reflection layer and the temperature, the apparatus shown in FIG. 4 was used to heat the stainless steel substrate on which the light reflection layer was formed. Was done. First, the stainless steel substrate on which the light reflection layer is formed is attached to the heater 403 so that the light reflection layer faces downward, the inside of the deposition chamber 401 is evacuated by a vacuum pump (not shown), and the vacuum gauge 408 reads about 1 × 10 ^{−. When the} pressure reaches ⁶ Torr, the gas introduction valve 410 is gradually opened, and the Ar gas flow rate becomes 100 sccm.
, And the opening of the conductance valve 409 was adjusted so that the pressure in the deposition chamber 401 became 8 mTorr. Next, electric power was supplied to the heater 403, and the temperature of the stainless substrate 402 was adjusted to 400 ° C. by a temperature controller (not shown). After performing the heating annealing for 3 hours, the power supply to the heater is stopped, and the conductance valve 40 is controlled so that the pressure in the deposition chamber 401 becomes 10 Torr.
The opening of No. 9 was adjusted, and the stainless steel substrate 402 was gradually cooled.
When the temperature of the stainless substrate 402 has dropped to room temperature, the conductance valve 409 is closed and the deposition chamber 401 is closed.
Was leaked, and the stainless steel substrate was taken out.

The crystal grain size of each stainless steel substrate taken out was examined in the same manner by using a scanning electron microscope using (evaluation a). As a result, Experimental Examples 1-1 to 1-
As shown in FIG. 7A, no change was observed in the crystal grain size of the sample No. 4 due to the heat annealing (average grain size: 0.2 μm). On the other hand, as shown in FIG. 7B, it was found that the average grain size of the sample of Comparative Experimental Example 1 increased from 0.2 μm to 0.5 μm due to annealing.

(Evaluation d) Adhesion in Laminated Structure In order to evaluate the adhesion in the case of the laminated structure, a light reflection increasing layer of zinc oxide (ZnO) was formed on the light reflection layer.

First, the same light reflection layers as those of Experimental Examples 1-1 to 1-4 and Comparative Experimental Example 1 were formed on a substrate by a DC magnetron sputtering apparatus shown in FIG. Experimental example 1-1
The shutter 807 is opened according to the same procedure as in steps 1-4 to start production of the AlSi light reflection layer on the substrate 802. When the light reflection layer having a thickness of 450 nm is produced, the shutter 807 is closed and the DC power supply 806 is turned off. Turn off the output, D
C glow discharge was stopped. Next, close the gas introduction valve,
Evacuation was sufficiently performed again until the pressure in the deposition chamber 801 became 1 × 10 ⁻⁶ Torr.

Next, a light reflection increasing layer of zinc oxide (ZnO) was formed on the light reflection layer of AlSi. 818 in the figure is
A zinc oxide (ZnO) target with a purity of 99.99%, which is insulated from the deposition chamber 801 by an insulating support 805. First, the gas introduction valve 810 is gradually opened, and Ar
The mass flow controller 811 was adjusted so that the gas flow rate was 30 sccm, and the pressure in the deposition chamber 801 was 6 m.
The opening of the conductance valve 809 was adjusted to be Torr. Then, the voltage of the DC power supply 820 is
The voltage was set to 00 V, and DC power was introduced to the ZnO target 818 to generate DC glow discharge. After a lapse of 5 minutes, the shutter 821 is opened to start forming a ZnO light reflection increasing layer on the AlSi light reflection layer.
When the light reflection increase amount of 0 μm was produced, the shutter 8
21 was closed, the output of the DC power supply 820 was turned off, and the DC glow discharge was stopped. Next, the flow rate of Ar gas is 100 sccm.
The mass flow controller 811 is adjusted so as to satisfy the condition, the conductance valve 809 is closed, and the deposition chamber 80 is closed.
1 was gradually leaked, and the production of the ZnO light reflection increase amount was completed.

Similarly, a ZnO light reflection increasing layer was formed on the light reflection layer of Comparative Experimental Example 1. The above samples were evaluated for adhesion in the same manner as in (Evaluation b). Table 2 shows the results.

As shown in Table 2, Experimental Examples 1-1 to 1-4
It was found that the sample of Example 2 showed less peeling of the film as compared with Comparative Example 1, and showed high adhesion even in the case of a laminated structure.

(Experimental example 2-1) A light reflecting layer of AlSi of the present invention was manufactured by electron beam (EB) vacuum evaporation.

First, a light reflecting layer of AlSi containing oxygen atoms was formed on a substrate by a manufacturing apparatus using an electron beam (EB) vacuum evaporation method shown in FIG.

In the figure, 902 is the same as the stainless steel substrate used in Experimental Example 1, and 904 is 99.999 purity.
% Of AlSi for EB evaporation. 91 in the figure
0, 912, 914, 916 are gas introduction valves,
Argon (Ar) cylinders (purity 99.
999%), a nitrogen (N ₂ / Ar) gas cylinder diluted to 50 ppm with argon (Ar) gas, argon (A)
r) Methane (CH ₄ / A) diluted to 50 ppm with gas
r) Gas cylinder, connected to an oxygen (O ₂ / Ar) gas cylinder diluted to 50 ppm with argon (Ar) gas. First, the inside of the deposition chamber 901 is evacuated by a vacuum pump (not shown), and the vacuum gauge 908 reads about 1 × 10 ⁻⁶ Torr.
At this point, the gas introduction valve 916 is gradually opened, and the mass flow controller 917 adjusts the flow rate of the O ₂ / Ar gas to ₂ sccm.
Vacuum gauge 9 so that the internal pressure becomes 1 × 10 ⁻⁴ Torr.
08 conductance valve (butterfly type)
The opening of 909 was adjusted. Thereafter, a high voltage was applied to the electron gun 905, and the voltage of the high-voltage power supply 906 was adjusted so that the film formation rate was 2.5 A / sec. After a lapse of 5 minutes, the shutter 907 is opened to start manufacturing a light reflecting layer of AlSi on the substrate 902. When a light reflecting layer having a thickness of 450 nm is formed, the shutter 907 is closed and the output of the high voltage power supply 906 is turned off. , EB vacuum deposition was completed. Next, the gas introduction valve 916 is closed, and O
The flow of the ₂ / Ar gas was stopped, the gas introduction valve 910 was opened, and the mass flow controller 911 was adjusted so that the flow rate of the Ar gas became 100 sccm.

Next, the conductance valve 909 is closed, the deposition chamber 901 is gradually leaked, and the A
The fabrication of the 1Si light reflecting layer was completed.

(Experimental example 2-2) In Experimental example 2-1,
Instead of oxygen gas diluted with Ar gas, 5
Experimental Example 2 was used except that CH ₄ gas diluted to 0 ppm was used.
In the same manner as in Example 1, an AlSi light reflecting layer containing carbon atoms was produced.

(Experimental example 2-3) In Experimental example 2-1,
Instead of oxygen gas diluted with Ar gas, 5
Experimental Example 2-1 using N ₂ gas diluted to 0 ppm
In the same manner as in the above, an AlSi light reflecting layer containing a nitrogen atom was produced.

(Experimental example 2-4) Alkali metal atom (L
i, Na, K, Rb, Cs), an aluminum-silicon alloy (Al
Except that Si) was used as the evaporation source and no gas was introduced, the alkali metal atoms (Li, Na,
K, Rb, Cs) was prepared.

(Comparative Experimental Example 2) No O ₂ / Ar gas was flowed into the deposition chamber 901 during fabrication of the light reflecting layer.
A conventional light reflecting layer was produced in the same manner as in Example 1.

As described above, the two AlSs formed by the vacuum evaporation method were used.
Evaluation tests similar to those of Experimental Examples 1-1 to 1-4 and Comparative Experimental Example 1 were performed on the light reflecting layer of i to demonstrate the effects of the present invention.

(Evaluation a) FIG. 10 shows the variation in the crystal grain size of AlSi in the light reflection layer. In Experimental Examples 2-1 to 2-4, almost no difference was observed, and as is clear from the figure, the samples of Experimental Examples 2-1 to 2-4 were the same as Comparative Experimental Example 2.
Crystal grain size (average grain size 0.1μm)
Was found to be small.

(Evaluation b) Table 3 shows the results of the evaluation of the adhesion of the light reflection film by the bending test.

As shown in Table 3, Experimental Examples 2-1 to 2-4
It can be seen that the light reflecting layer of No. 1 shows excellent adhesion as compared with the conventional example.

(Evaluation c) FIG. 11 shows the measurement results of the temperature dependence of the crystal grain size of AlSi in the light reflection layer. Experimental example 2-1
~ 2-4 gave almost the same results. As is clear from the figure, in the samples of Experimental Examples 2-1 to 2-4, there is almost no change in the crystal grain size due to the heat annealing.
In Comparative Example 2, it was found that the crystal grain size was large.

(Evaluation d) In order to evaluate the adhesion in the case of the laminated structure, zinc oxide (Z
nO) was formed.

Using an apparatus having both the EB vacuum deposition method and the DC magnetron sputtering method shown in FIG. 12, an experimental example 2-1 was first formed on a stainless steel substrate by the EB vacuum deposition method.
2 to 4-4 were prepared. In the drawing, reference numeral 1202 denotes a stainless steel substrate, and 1204 denotes E having a purity of 99.999%.
It is an evaporation source of AlSi for B evaporation.

In the figure, 1210, 1212, 1214, 12
Reference numeral 16 denotes a gas introduction valve, each of which is described in Experimental Examples 2-1 to 2-1.
The same cylinder as 2-4 is connected (not shown). The procedure is the same as in Experimental Examples 2-1 to 2-4.

Next, a light reflection increasing layer of zinc oxide (ZnO) was formed on the light reflection layer of AlSi.

In the figure, reference numeral 1218 denotes a zinc oxide (ZnO) target having a purity of 99.99%.
9 is insulated from the deposition chamber 1201. First, AlS
The substrate 1202 on which the light reflection layer of the i
03, and maintained at 350 ° C.
10 is gradually opened, and the mass flow controller 1211 is adjusted so that the Ar gas flow rate becomes 20 sccm,
The pressure in the deposition chamber 1201 is set to 5 mTorr.
The opening of the conductance valve 1209 was adjusted. Then, the voltage of the DC power supply 1220 is set to -400V,
DC power is introduced into the ZnO target 1218,
A glow discharge was generated.

After elapse of 5 minutes, the shutter 1221 is opened to start the formation of the ZnO light reflection increasing layer on the AlSi light reflection layer. When the light reflection increasing layer having a thickness of 1.0 μm is formed, the shutter 1221 is opened. And close the DC power supply 12
20 was turned off, and DC glow discharge was stopped. Next, A
The mass flow controller 1212 was adjusted so that the flow rate of the r gas became 100 sccm, the conductance valve 1209 was closed, the deposition chamber 1201 was gradually leaked, and the formation of the ZnO light reflection increasing layer was completed.

Similarly, the same amount of ZnO light reflection increase as described above was formed on the light reflection layer of Comparative Experimental Example 2.

The adhesion of the laminated structure manufactured as described above was evaluated by the method described above. Table 4 shows the results.

As apparent from Table 4, Experimental Examples 2-1 to 2-1
It can be seen that the light reflecting layer of 2-4 has a higher adhesion than the comparative example even in the case of a laminated structure. As described above, the light reflection layer of the present invention was found to be superior to the conventional light reflection layer as a result of four evaluation tests.

[0167]

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

Examples 1 to 4 and Comparative Example 1 (Example 1) A photovoltaic element having the structure shown in FIG. 1 was manufactured by a DC magnetron sputtering method and a microwave (hereinafter abbreviated as “μW”) glow discharge decomposition method. Produced.

An oxygen atom was contained on a 50 mm square, 0.2 mm thick mirror-polished stainless steel (SUS430) substrate in the same manner as in Experimental Example 1-1 by the DC magnetron sputtering manufacturing apparatus shown in FIG. AlSi
The light reflection layer of 450 nm and the light reflection increasing layer of 1 μm were produced.

Next, the raw material gas supply device 13 shown in FIG.
A non-single-crystal silicon-based semiconductor layer was formed on the light reflection-enhancing layer by a manufacturing apparatus including a deposition apparatus 1300 and a μW glow discharge decomposition method.

The gas cylinders 1371 to 1376 in the figure are sealed with a source gas for producing the non-single-crystal silicon semiconductor layer of the present invention, and 1371 is a SiH ₄ gas (99.999% purity) cylinder. , 1372 H ₂ gas (99.9999% purity) cylinder, 1373 PH ₃ gas (99.99% pure diluted to 10% with H ₂ gas,
The "PH ₃ / H _2" and abbreviated) bomb, 1374 was diluted to 10% with H ₂ gas B ₂ H ₆ gas (purity 9
9.99%, hereinafter abbreviated as “B ₂ H ₆ / H ₂ ”) cylinder, 1375 is a CH ₄ gas (purity 99.9999%) cylinder, and 1376 is a GeH ₄ gas (purity 99.99%) cylinder. . In addition, gas cylinders 1371 to
When installing 1376, each gas is supplied to valve 13
From 51 to 1356, they are introduced into the gas pipes of the inflow valves 1331 to 1336.

In the figure, reference numeral 1304 denotes a substrate on which a light reflecting layer and a light reflection increasing layer are formed by the above-described method.

First, SiH ₄ gas is supplied from the gas cylinder 1371, H ₂ gas is supplied from the gas cylinder 1372, and the gas cylinder 13 is released.
PH ₃ / H ₂ gas from 73, B from gas cylinder 1374
₂ H ₆ / H ₂ gas, CH ₄ gas from gas cylinder 1375, GeH ₄ gas from gas cylinder 1376, valve 1
351 to 1356 are opened and introduced, and the pressure regulator 1361 is opened.
According to 圧 力 1366, each gas pressure was adjusted to about 2 kg / cm ² .

Next, it is confirmed that the inflow valves 1331 to 1336 and the leak valve 1309 of the deposition chamber 1301 are closed.
After confirming that the auxiliary valve 1308 is opened, the conductance (butterfly type) valve 1307 is fully opened, and the inside of the deposition chamber 1301 and the gas pipe is evacuated by a vacuum pump (not shown). 1 × 10
Outflow valves 1341 to 134 when ^-4 Torr is reached
6 was closed.

Next, the inflow valves 1331 to 1336 are gradually opened, and each gas is supplied to the mass flow controller 1.
321 to 1326.

After the preparation for film formation was completed as described above, an n-type layer, an i-type layer, and a p-type layer were formed on the substrate 1304.

In order to form an n-type layer, the substrate 1304 is heated to 350 ° C. by the heater 1305, and the outflow valves 1341 to 1343 are gradually opened, and the SiH ₄ gas,
H ₂ gas, PH ₃ / H ₂ gas flow rate is 30 sccm, H ₂ gas
Gas flow rate is 100 sccm, PH ₃ / H ₃ gas flow rate is 6
The mass flow controllers 1321 to 1323 were adjusted to be sccm. The opening of the conductance valve 1307 was adjusted while watching the vacuum gauge 1306 so that the pressure in the deposition chamber 1301 became 10 mTorr. After that, the power of a μW power supply (not shown) is increased to 50 mW / cm.
^It is set to ³ , and μW power is introduced into the deposition chamber 1301 through the waveguide, the waveguide portion 1310 and the dielectric window 1302 (not shown) to generate μW glow discharge, and n is formed on the light reflection increasing layer.
The production of the mold layer was started, and when the n-type layer having a layer thickness of 10 nm was produced, the μW glow discharge was stopped.
1343 and the auxiliary valve 1308 are closed, and the deposition chamber 13 is closed.
The flow of gas into 01 was stopped, and the fabrication of the n-type layer was completed.

Next, in order to produce an i-type layer, the substrate 130
4 was heated to 350 ° C. by the heater 1305, and the outflow valves 1341 and 1342 were gradually opened to obtain SiH _4.
Gas and H ₂ gas through the gas introduction pipe 1303 to the deposition chamber 1
It flowed into 301. At this time, the flow rate of the SiH ₄ gas is
Each of the mass flow controllers 1321 and 13 is set so that the flow rate of H ₂ gas becomes 100 sccm and the flow rate of H ₂ gas becomes 200 sccm.
Adjusted at 22. The pressure in the deposition chamber 1301 is 5 mTo
The opening of the conductance valve 1307 was adjusted while looking at the vacuum gauge 1306 so as to obtain rr. Next, the high frequency (hereinafter abbreviated as “RF”) bias of the bias power supply is set to 1
At 00 mW / cm ³ , the DC bias was set to 75 V with respect to the substrate 1304 and applied to the bias bar 1312. After that, the power of a μW power supply (not shown) is set to 100 mW / cm ³ , and μW power is introduced into the deposition chamber 1301 through a waveguide (not shown), a waveguide section 1310, and a dielectric window 1302 to perform μW glow discharge. Then, the production of the i-type layer was started on the n-type layer. When the i-type layer having a thickness of 400 nm was produced, the μW glow discharge was stopped, the output of the bias power supply 1311 was turned off, and the production of the i-type layer was completed. .

In order to form a p-type layer, the substrate 1304 is heated to 300 ° C. by the heater 1305, and the outflow valve 1344 is gradually opened, and the SiH ₄ gas, H ₂ gas,
B ₂ H ₆ / H ₂ gas was caused to flow into the deposition chamber 1301 through the gas introduction pipe 1303. At this time, SiH ₄ gas flow rate 10 sccm, H ₂ gas flow rate 100 sccm, B ₂
Each of the mass flow controllers 1321, 1322, 1324 so that the H ₆ / H ₂ gas flow rate is 5 sccm.
Was adjusted. The pressure in the deposition chamber 1301 is 20 mTorr
The opening of the conductance valve 1007 was adjusted while watching the vacuum gauge 1306 so as to obtain r. Thereafter, the power of the μW power supply is set to 400 mW / cm ³ , and μW power is introduced into the deposition chamber 1301 through a waveguide (not shown), a waveguide 1310 and a dielectric window 1302 to generate a μW glow discharge, Preparation of the p-type layer on the i-type layer is started, and the layer thickness is 5 nm.
When the p-type layer was formed, the μW glow discharge was stopped, the outflow valves 1341, 1342, 1344 and the auxiliary valve 1308 were closed, the gas flow into the deposition chamber 1301 was stopped, and the p-type layer was completed.

When producing the respective layers, it goes without saying that the outflow valves 1341 to 1346 other than the necessary gas are completely closed, and the respective gases are stored in the deposition chamber 1301 and outflow valves 1341 to 1346. Outflow valves 1341 to 1346, auxiliary valve 1308 is opened, and conductance valve 1301
7 is fully opened, and the operation of once evacuating the system to a high vacuum is performed as necessary.

Next, on the p-type layer, as a transparent electrode, IT
O (In ₂ O ₃ + SnO ₂ ) was vapor-deposited to a thickness of 80 nm by vacuum vapor deposition, and Cr was vapor-deposited to a thickness of 1 μm as a current collecting electrode to produce a photovoltaic device (device example 1). Table 5 shows the conditions for manufacturing the photovoltaic element described above.

Example 2 Under the conditions of Experimental Example 1-2, a light reflecting layer of 450 nm AlSi containing carbon atoms and a light reflection increasing layer of 1 nm were formed on a stainless steel substrate in the same manner as in Example 1.
μm was formed. Subsequently, the n-type layer,
An i-type layer, a p-type layer, a transparent electrode, and a current collecting electrode were formed to produce the photovoltaic element of FIG. 1 (element example 2).

Example 3 Under the conditions of Experimental Examples 1-3, a light reflecting layer of AlSi containing nitrogen atoms was 450 nm on a stainless steel substrate and a light reflection increasing layer was 1 on a stainless steel substrate in the same manner as in Example 1.
μm was formed. Subsequently, the n-type layer,
An i-type layer, a p-type layer, a transparent electrode, and a current collecting electrode were formed to produce the photovoltaic element of FIG. 1 (element example 3).

Example 4 An alkali metal (L) was formed on a stainless steel substrate in the same manner as in Example 1 under the conditions of Experimental Examples 1-4.
i, Na, K, Rb, Cs)
The light reflection layer was formed at 450 nm, and the light reflection increasing layer was formed at 1 μm. Subsequently, the n-type layer, the i-type layer, the p-type
A mold layer, a transparent electrode, and a current collecting electrode were formed to produce the photovoltaic element of FIG. 1 (element examples 4-1 to 4-5).

Comparative Example 1 A conventional photovoltaic device was manufactured in the same manner as in Example 1.

First, an AlSi light reflecting layer containing no oxygen atoms was formed on a substrate to a thickness of 450 nm by a method similar to that of Comparative Experiment 1 using a DC magnetron sputtering apparatus shown in FIG.

Next, under the same manufacturing conditions as in Example 1, a light 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 on the light reflecting layer, and the A power element was manufactured (element ratio 1).

For the photovoltaic devices of Examples 1 to 4 and Comparative Example 1 manufactured as described above, the following three evaluations were performed in order to demonstrate the effects of the present invention. (A) Initial characteristics (B) Dependence of characteristics on adhesion (C) Dependence of characteristics on environmental change In order to examine the initial characteristics of the photovoltaic device and the solar cell characteristics, the photovoltaic device was subjected to AM-1.5 (100 mW). / C
m ² ) Installed under light irradiation and evaluated by photoelectric conversion efficiency obtained by measuring V-1 characteristics. Table 6 shows the results.

As shown in Table 6, the photovoltaic elements of Examples 1 to 4 have higher photoelectric conversion efficiency than the photovoltaic element of Comparative Example 1, and the oxygen atom, carbon atom, and nitrogen atom of the present invention. Alternatively, a photovoltaic device using a light reflecting layer containing an alkali metal atom shows superior characteristics as compared with a photovoltaic device using a conventional light reflecting layer. (B) Adhesion Dependence of Characteristics In order to examine the dependence of the solar cell characteristics on the adhesion of the photovoltaic element, the photovoltaic element was deposited using a bending tester as shown in FIG. A 601 bending test was performed on the stainless steel substrate thus subjected.

As for the characteristics, the photoelectric conversion efficiency was measured as described above, and then the surface 60 on which the photovoltaic element was deposited was measured.
1a is turned to the right, the end of the stainless steel substrate 601 is firmly fixed so that it slightly contacts the tip of the bending rod 602, and then compressed air is introduced into the air cylinder 603, and the extrusion speed of the bending rod is about 1 m / s, the retraction speed was about 1 m / s, and the pressure of the compressed air was adjusted so that the stroke was 3.0 cm. After performing a bending test 10,000 times in a normal atmosphere, the sample was again irradiated with AM-1.5 light. ,
The photoelectric conversion efficiency was measured. Table 6 summarizes the measurement results.

From these results, the photoelectric conversion efficiencies of the photovoltaic elements of Examples 1 to 4 were higher than those of Comparative Example 1, and the oxygen, carbon, nitrogen, or alkali metal atom of the present invention was used. The photovoltaic device using the light reflecting layer containing the compound showed excellent durability as compared with the conventional photovoltaic device. (C) Dependence of Characteristics on Environmental Change The photovoltaic element was left in a dark place at a relative temperature of 85% at a temperature of 85 ° C., and subjected to a heat cycle of 85 ° C. for 4 hours and a temperature of −40 ° C. for 40 minutes for 30 minutes. This was repeated twice and the photoelectric conversion efficiency was examined. Table 6 shows the results.

As is clear from the table, in the photovoltaic elements of Examples 1 to 4, a decrease in the photoelectric conversion efficiency due to the heat cycle was suppressed, and the environmental resistance was higher than that of the photovoltaic element of Comparative Example 1. It turned out to be excellent.

From the above evaluation tests, it was found that the photovoltaic device using the light reflecting layer containing an oxygen atom of the present invention had better environmental resistance than the conventional photovoltaic device. The effect of the present invention was demonstrated.

Examples 5 to 8 and Comparative Example 2 (Example 5) A photovoltaic device of the present invention was manufactured by a DC magnetron sputtering method and a radio frequency (RF) glow discharge decomposition method.

First, under the same manufacturing conditions as in Example 1, a 450 nm-thick AlSi light reflecting layer containing oxygen atoms and a 1 μm-thick light reflection increasing layer were formed on a substrate using the DC magnetron sputtering apparatus shown in FIG.

Next, the source gas supply device 13 shown in FIG.
A non-single-crystal silicon-based semiconductor layer was formed on the light reflection-enhancing layer by a manufacturing apparatus including an RF glow discharge decomposition method and a deposition apparatus 1400.

In the figure, reference numeral 1404 denotes a substrate on which the light reflection increasing layer and the light reflection layer described above are formed. In the figure, gas cylinder 1
The same source gas as in Example 1 is sealed in each of the gas cylinders 371 to 1376, and each gas is supplied to the mass flow controllers 1321 to 1321 by the same operation procedure as in Example 1.
326.

After the preparation for film formation was completed as described above, an n-type layer, an i-type layer, and a p-type layer were formed on the substrate 1404.

In order to form an n-type layer, the substrate 1404 is heated to 300 ° C. by the heater 1405, and the outflow valves 1341 to 1343 and the auxiliary valve 1408 are opened gradually, and SiH ₄ gas, H ₂ gas, PH ₃ / H ₂ gas was introduced into the deposition chamber 1401 through the gas introduction pipe 1403. At this time, the flow rate of the SiH ₄ gas is ₂ sccm, the flow rate of the H ₂ gas is 20 sccm, and the flow rate of the PH ₃ / H ₂ gas is 1 sccm.
cm each mass flow controller 13
Adjusted at 21 to 1323. The opening of the conductance valve 1407 was adjusted while watching the vacuum gauge 1406 so that the pressure in the deposition chamber 1401 became 1 Torr. Thereafter, the power of an RF power source (not shown) is set to 5 mW / cm ³ , and RF power is introduced to the cathode 1402 through the RF matching box 1412 to generate RF glow discharge, thereby forming an n-type layer on the light reflection increasing layer. To start with a layer thickness of 10
The RF glow discharge was stopped at the time when the n-type layer of nm was produced, the outflow valves 1341 to 1343 were closed, and the deposition chamber 1 was closed.
The gas flow into 401 was stopped, and the fabrication of the n-type layer was completed.

Next, in order to form an i-type layer, the substrate 140
4 was heated to 300 ° C. by the heater 1405, by gradually opening the discharge valves 1341 and 1342, SiH ₄
Gas and H ₂ gas are supplied through the gas introduction pipe 1403 to the deposition chamber 1
It flowed into 401. At this time, the flow rate of the SiH ₄ gas is 2
The mass flow controllers 1321 and 1322 adjusted the flow rates of sccm and H ₂ gas to 20 sccm. The opening of the conductance valve 1407 was adjusted while watching the vacuum gauge 1406 so that the pressure in the deposition chamber 1041 became 1 Torr. After that, the power of an RF power source (not shown) is set to 5 mW / cm ³ , RF power is introduced to the cathode 1402 through the RF matching box 1412 to generate RF glow discharge, and the i-type layer is formed on the p-type layer. Starting, the RF glow discharge was stopped at the time when an i-type layer having a thickness of 400 μm was produced, and the production of the i-type layer was completed.

Next, to form a p-type layer, the substrate 1404
Was heated to 250 ° C. by the heater 1405, the outflow valve 1344 was gradually opened, and SiH ₄ gas, H ₂ gas, and B ₂ H ₆ / H ₂ gas were introduced into the deposition chamber 1401 through the gas introduction pipe 1403. . At this time, SiH ₄ gas flow rate 2 sccm, H ₂ gas flow rate 50 sccm, B ₂
Each mass flow controller 1321, 1322, 1324 so that the flow rate of H ₆ / H ₂ gas is 1 sccm.
Was adjusted. The opening of the conductance valve 1407 was adjusted while watching the vacuum gauge 1406 so that the pressure in the deposition chamber 1401 became 1 Torr. Then, RF (not shown)
The power of the power supply was set to 200 mW / cm ³ , and RF was applied to the cathode 1402 through the RF matching box 1412.
Electric power was introduced to generate an RF glow discharge, a p-type layer was started to be formed on the i-type layer, and the RF glow discharge was stopped after a p-type layer having a thickness of 5 nm was formed.
By closing 1342, 1344 and the auxiliary valve 1408,
The gas flow into the deposition chamber 1401 was stopped, and the formation of the p-type layer was completed.

When producing each layer, it goes without saying that the outflow valves 1341 to 1346 other than the necessary gas are completely closed, and the respective gases are supplied into the deposition chamber 1401 and outflow valves 1341 to 1346. In order to avoid remaining in the piping from the flow to the deposition chamber 1401, the outflow valves 1341 to 1346 are closed, the auxiliary valve 1408 is opened, and the conductance valve 1401 is opened.
7 is fully opened, and the operation of once evacuating the system to a high vacuum is performed as required.

Next, on the p-type layer, an IT
O (In ₂ O ₃ + SnO ₂ ) was vapor-deposited to a thickness of 80 nm, and Cr was vapor-deposited as a current collecting electrode to a thickness of 1 μm to produce a photovoltaic device (device example 5). Table 7 shows the conditions for manufacturing the photovoltaic element described above.

(Example 6) A light reflecting layer of AlSi containing carbon atoms was formed on a stainless steel substrate in the same manner as in Example 2, and a light reflection increasing layer was formed thereon in the same manner as in Example 5.
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 photovoltaic element (element 6).

Example 7 A light reflecting layer of AlSi containing nitrogen atoms was formed on a stainless steel substrate in the same manner as in Example 3, and a light reflection increasing layer was formed thereon in the same manner as in Example 5.
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 photovoltaic element (element example 7).

(Example 8) In the same manner as in Example 4, an alkali metal (Li, Na, K, Rb, C
s) is formed, and a light reflection increasing layer, an n-type layer and an i-type layer are formed thereon in the same manner as in Example 5.
A photovoltaic element was manufactured by forming a mold layer, a p-type layer, a transparent electrode, and a current collecting electrode (element examples 8-1 to 8-5).

(Comparative Example 2) A light reflecting layer was formed in the same manner as in Comparative Example 1, and then a light reflection increasing layer, a semiconductor layer, a transparent electrode, and a collecting electrode were formed in the same manner as in Example 5. A conventional photovoltaic element was manufactured (element ratio 2).

In order to demonstrate the effect of the present invention on the solar cell characteristics of the photovoltaic elements manufactured in Examples 5 to 8 and Comparative Example 2, the same evaluation test as in Example 1 was performed. Table 8 shows the results.

As is clear from Table 8, the photovoltaic elements of Examples 5 to 8 have significantly improved durability and environmental resistance as well as the initial characteristics as compared with the element of Comparative Example 2. Was. Ninth Embodiment As in the first embodiment, the flow rate of the O ₂ gas introduced into the deposition chamber 801 on the substrate by the DC magnetron sputtering method shown in FIG. 0.1 to 25,000 for gas flow rate
ppm to change the content of Al
A 450 nm Si light reflection layer was formed. Next, with respect to the substrate on which each light reflection layer was deposited, a part of the substrate was subjected to secondary ion mass spectrometry (SIMS) to measure the amount of oxygen in the AlSi light reflection layer.

As a result, it was found that the amount of oxygen atoms contained in the produced light reflecting layer was 0.05 ppm to 2,500 ppm.

Next, as in the first embodiment, the DC shown in FIG.
A light reflection increasing layer having a thickness of 1 μm is deposited on the light reflection layer containing the respective amounts of oxygen atoms by a magnetron sputtering method manufacturing apparatus.
A non-single-crystal silicon-based semiconductor layer, a transparent electrode,
Current collecting electrodes were laminated to produce a photovoltaic element (element 9
-1 to 9-9).

An evaluation test similar to that of Example 1 was conducted for the solar cell characteristics of these photovoltaic elements. Table 9 shows the results.

As is clear from Table 9, when the amount of oxygen atoms contained in the light reflecting layer is in the range of 0.1 ppm to 1000 ppm, the photovoltaic element has the amount of oxygen atoms of 0.1 ppm. For a photovoltaic element of 1000 ppm or less, the initial characteristics of the photoelectric conversion characteristics, the characteristics after the adhesion test and after the environmental test also show high values, and the light reflecting layer containing 0.1 ppm to 1000 ppm of oxygen atoms. It has been found that a higher effect can be obtained by using.

Example 10 As in Example 2, the flow rate of the CH ₄ gas introduced into the deposition chamber 801 on the substrate in the same manner as in Example 2 by the DC magnetron sputtering manufacturing apparatus shown in FIG. From 1 to the Ar gas flow rate.
The light reflecting layer of AlSi having a different carbon atom content was formed at 450 nm by changing the concentration to 10,000 ppm. Next, secondary ion mass spectrometry (SIMS) was performed on a part of the substrate on which each light reflection layer was
The amount of carbon in the light reflecting layer of Si was measured.

As a result, it was found that the amount of carbon atoms contained in the produced light reflecting layer was 0.05 ppm to 1,500 ppm.

Next, as in the first embodiment, the DC shown in FIG.
A light reflection increasing layer having a thickness of 1 μm is deposited on the light reflection layer containing the respective amounts of carbon atoms by a magnetron sputtering method manufacturing apparatus.
A non-single-crystal silicon-based semiconductor layer, a transparent electrode,
A current collecting electrode was laminated to produce a photovoltaic element (element 1).
0-1 to 10-9). An evaluation test similar to that of Example 1 was performed on the solar cell characteristics of these photovoltaic elements. Table 10 shows the results.

As is clear from Table 10, when the amount of carbon atoms contained in the light reflecting layer is in the range of 0.1 ppm to 1000 ppm, the photovoltaic element has the amount of carbon atoms of 0.1 ppm. For the photovoltaic element of 1000 ppm or less, the initial property of the photoelectric conversion property, the property after the adhesion test and the property after the environmental test also show a high value, and the light reflecting layer containing 0.1 ppm to 1000 ppm of carbon atoms. It has been found that a higher effect can be obtained by using.

(Embodiment 11) As in Embodiment 3, the flow rate of N ₂ gas introduced into the deposition chamber 801 on the substrate by the DC magnetron sputtering method shown in FIG. Is 1 pp to the Ar gas flow rate.
The light reflecting layer of AlSi having a different carbon atom content was produced at a thickness of 450 nm while changing the content from m to 10,000 ppm. Next, for the substrate on which each light reflection layer is deposited,
Secondary ion mass spectrometry (SIMS) was performed using a part of the sample to measure the amount of nitrogen in the AlSi light reflecting layer.

As a result, it was found that the amount of carbon atoms contained in the produced light reflecting layer was from 0.05 ppm to 1,500 ppm.

Next, as in the first embodiment, the DC shown in FIG.
A 1 μm thick light reflection-enhancing layer is deposited on the light reflection layer containing the respective amounts of nitrogen atoms by a magnetron sputtering method manufacturing apparatus.
A non-single-crystal silicon-based semiconductor layer, a transparent electrode,
A current collecting electrode was laminated to produce a photovoltaic element (element 1).
1-1 to 11-9).

An evaluation test similar to that of Example 1 was conducted for the solar cell characteristics of these photovoltaic elements. Table 11 shows the results.
Shown in

As is clear from Table 11, the amount of nitrogen atoms contained in the light reflecting layer was from 0.1 ppm to 1000 ppm.
When the photovoltaic element is within the range, the amount of the nitrogen atom is 0.1 ppm or less, or the photovoltaic element of 1000 ppm or more, the initial characteristics of the photoelectric conversion characteristics, after the adhesion test and the environmental test. The subsequent characteristics also showed high values, and it was found that higher effects could be obtained by using the light reflecting layer containing 0.1 to 1000 ppm of nitrogen atoms.

Example 12 Similarly to Example 4, an alkali metal atom to be added to an aluminum-silicon alloy target on a substrate in the same manner as in Example 4 by a DC magnetron sputtering manufacturing apparatus shown in FIG. (L
By changing the amount of i, Na, K, Rb, Cs), 450 nm AlSi light reflecting layers having different contents of alkali metal atoms (Li, Na, K, Rb, Cs) were produced.

Next, with respect to the substrate on which each light reflection layer was deposited, a part thereof was used for secondary ion mass spectrometry (SIM).
S) was performed to measure the amount of alkali metal atoms (Li, Na, K, Rb, Cs) in the AlSi light reflecting layer.

As a result, it was found that the amount of the alkali metal atoms (Li, Na, K, Rb, Cs) contained in the produced light reflecting layer was from 1.5 ppm to 200 ppm.

Next, as in the first embodiment, the DC shown in FIG.
Each amount of alkali metal atoms (Li, Na, K, Rb, C
A light reflection increasing layer having a thickness of 1 μm is deposited on the light reflection layer containing s), and the light reflection increasing layer is further formed on the light reflection increasing layer by a production apparatus using a μW glow discharge decomposition method shown in FIG. A non-single-crystal silicon-based semiconductor layer, a transparent electrode, and a current collecting electrode were laminated to produce a photovoltaic element (element 12-1-1)
１２12-5-9). An evaluation test similar to that of Example 1 was performed on the solar cell characteristics of these photovoltaic elements. The results are shown in Tables 12-1 to 12-5.

As is clear from Tables 12-1 to 12-5, the alkali metal atoms (Li, N
a, K, Rb, Cs) from 2 ppm to 100 ppm
When the amount of the alkali metal atom (Li, Na, K, Rb, Cs) is 2 pp
m or 100 ppm or more, the initial characteristics of the photoelectric conversion characteristics, the characteristics after the adhesion test and after the environmental test also show high values, and the alkali metal atoms (Li,
It has been found that a higher effect can be obtained by using the light reflecting layer containing 2 ppm to 100 ppm of (Na, K, Rb, Cs).

Examples 13 to 16 and Comparative Example 3 (Example 13) A 50 mm square, 1 mm thick barium borosilicate glass (7059, manufactured by Corning Incorporated) was used as a substrate, and 1TO was used as a transparent electrode on the substrate. After forming the first p-type layer and the first i-type layer under the conditions shown in Table 13,
A type layer, a first n-type layer, a second p-type layer, a second i-type layer, and a second n-type layer are formed, and the light reflection increasing layer and the oxygen atoms are formed by the method of the first embodiment. A light reflecting layer of AlSi was produced to produce a photovoltaic device shown in FIG.
3).

Example 14 A 50 mm square, 1 mm thick barium borosilicate glass (7059, manufactured by Corning Incorporated) was used as a substrate, and 1TO was used as a transparent electrode on the substrate.
After the fabrication of 0 nm, the first p-type layer, the first i-type layer, the first n-type layer, the second p-type layer, and the second
Then, an i-type layer and a second n-type layer of
A light reflection increasing layer and a light reflection layer of AlSi containing carbon atoms were prepared to produce the photovoltaic device shown in FIG. 2 (device example 14).

(Example 15) A 50 mm square, 1 mm thick barium borosilicate glass (7059, manufactured by Corning Incorporated) was used as a substrate, and 1TO was used as a transparent electrode on the substrate.
After the fabrication of 0 nm, the first p-type layer, the first i-type layer, the first n-type layer, the second p-type layer, and the second
The i-type layer and the second n-type layer are formed, and the method of Example 3
A light reflection increasing layer and a light reflection layer of AlSi containing a nitrogen atom were prepared to produce a photovoltaic element shown in FIG. 2 (element example 15).

(Example 16) A 50 mm square, 1 mm thick barium borosilicate glass (7059, manufactured by Corning Incorporated) was used for a substrate, and 1TO was used as a transparent electrode on the substrate.
After the fabrication of 0 nm, the first p-type layer, the first i-type layer, the first n-type layer, the second p-type layer, and the second
The i-type layer and the second n-type layer were prepared, and the method of Example 4 was used.
A light reflection increasing layer, and an alkali metal atom (Li, Na,
A light-reflecting layer of AlSi containing (K, Rb, Cs) was produced to produce the photovoltaic device shown in FIG.
1 to 16-5).

(Comparative Example 3) As in Example 13, 80 mm of ITO was formed on a substrate as a transparent electrode.
A first p-type layer, a first i-type layer, a first n-type layer, a second p-type layer, a second i-type layer, and a second n-type layer are formed using the conditions In the same manner as in Comparative Example 1, a light reflection increasing layer and a light reflection layer containing no oxygen atom were prepared to produce a photovoltaic element (element ratio 3).

In order to demonstrate the effect of the present invention on the solar cell characteristics of the photovoltaic elements manufactured in Examples 13 to 16 and Comparative Example 3, the same evaluation test as in Example 1 was performed. 14

As can be seen from Table 14, Examples 13 to
It was found that the photovoltaic element No. 16 significantly improved not only the initial characteristics but also the durability and environmental resistance as compared with the element of Comparative Example 3.

Examples 17 to 20 and Comparative Example 4 (Example 17) A photovoltaic device of the present invention was manufactured by a DC magnetron sputtering method and a μW glow discharge decomposition method.

In the same manner as in Example 1, a DC magnetron sputtering apparatus shown in FIG.
A light reflection layer and a light reflection enhancement layer of AlSi having a layer thickness of 450 nm containing oxygen atoms were prepared. Next, using a production apparatus based on the μW Glee discharge decomposition method shown in FIG.
A non-single-crystal silicon-based semiconductor layer is formed on the light reflecting layer by a first n-type layer, a first i-type layer, a first p-type layer, a second n-type layer, and a second n-type layer.
, A second p-type layer, a third n-type layer, a third i-type layer, and a third p-type layer, and a transparent electrode and a current collecting electrode are further laminated. A triple-type photovoltaic element was manufactured (element example 17).

(Example 18) A photovoltaic device of the present invention was manufactured by a DC magnetron sputtering method and a μW glow discharge decomposition method.

In the same manner as in Example 2, a DC magnetron sputtering apparatus shown in FIG.
A light reflecting layer and a light reflection increasing layer of 450 nm thick AlSi containing carbon atoms were prepared. Next, using a production apparatus by μW Glee discharge decomposition method shown in FIG.
A non-single-crystal silicon-based semiconductor layer is formed on the light reflecting layer by a first n-type layer, a first i-type layer, a first p-type layer, a second n-type layer, and a second n-type layer.
, A second p-type layer, a third n-type layer, a third i-type layer, and a third p-type layer, and a transparent electrode and a current collecting electrode are further laminated. A triple-type photovoltaic element was manufactured (element example 18).

(Example 19) A photovoltaic device of the present invention was manufactured by a DC magnetron sputtering method and a μW glow discharge decomposition method.

In the same manner as in Example 3, a DC magnetron sputtering apparatus shown in FIG.
A light reflecting layer and a light reflection increasing layer of AlSi having a thickness of 450 nm containing a nitrogen atom were prepared. Next, using a production apparatus based on the μW Glee discharge decomposition method shown in FIG.
A non-single-crystal silicon-based semiconductor layer is formed on the light reflecting layer by a first n-type layer, a first i-type layer, a first p-type layer, a second n-type layer, and a second n-type layer.
, A second p-type layer, a third n-type layer, a third i-type layer, and a third p-type layer, and a transparent electrode and a current collecting electrode are further laminated. A triple-type photovoltaic element was manufactured (element example 19).

(Example 20) A photovoltaic device of the present invention was manufactured by a DC magnetron sputtering method and a μW glow discharge decomposition method.

In the same manner as in Example 4, a DC magnetron sputtering apparatus shown in FIG.
450 nm thick AlSi containing alkali metal atoms
Then, a non-single-crystal silicon-based semiconductor layer was formed on the light-reflecting layer using the conditions shown in Table 15 using a production apparatus based on the μW Glee discharge decomposition method shown in FIG. No. 1 n-type layer, first i-type layer, first p-type layer, second n-type layer, second i-type layer, second p-type layer, third n-type layer, third
, And a transparent electrode and a current collecting electrode were further laminated to produce triple-type photovoltaic elements (element examples 20-1 to 20-5). .

(Comparative Example 4) In the same manner as in Comparative Example 1, a light reflection layer and a light reflection increasing layer containing no oxygen atom were formed on a stainless steel substrate. A non-single-crystal silicon-based semiconductor layer was stacked on the light reflecting layer by a manufacturing apparatus based on the μW glow discharge decomposition method, and a transparent electrode and a current collecting electrode were stacked in the same manner and under the same conditions as in Example 17. An element was produced (element ratio 4).

In order to demonstrate the effect of the present invention on the solar cell characteristics of the photovoltaic elements produced in Examples 17 to 20 and Comparative Example 4, the same evaluation test as in Example 1 was performed. The results are summarized in Table 16.

As is clear from Table 16, Examples 17 to
It was found that the photovoltaic element No. 20 exhibited significantly improved initial properties, durability and environmental resistance as compared with the element of Comparative Example 4.

Examples 21 to 24 and Comparative Example 5 (Example 21) Electron beam (EB) vacuum evaporation method and DC
The photovoltaic device of the present invention was manufactured by a magnetron sputtering method and a μW glow discharge decomposition method.

Using the apparatus shown in FIG.
B) A 450 nm thick AlSi light reflecting layer containing oxygen atoms was formed on a stainless steel substrate by vacuum evaporation in the same manner as in Experimental Example 2-1. Zinc oxide (ZnO) was formed thereon by DC sputtering. Was formed. Next, in the same manner as in Example 17, a non-single-crystal silicon-based semiconductor layer was laminated on the light reflection increasing layer, and then a transparent electrode and a current collecting electrode were laminated to produce a photovoltaic device (device actual). 21).

(Example 22) Electron beam (EB) vacuum evaporation method, DC magnetron sputtering method, and μ
The photovoltaic device of the present invention was manufactured by the W glow discharge decomposition method.

Using the apparatus shown in FIG.
B) A 450 nm thick AlSi light reflecting layer containing carbon atoms was formed on a stainless steel substrate by vacuum evaporation in the same manner as in Experimental Example 2-2, and zinc oxide (ZnO) was formed thereon by DC sputtering. Was formed. Next, in the same manner as in Example 17, a non-single-crystal silicon-based semiconductor layer was laminated on the light reflection increasing layer, and then a transparent electrode and a current collecting electrode were laminated to produce a photovoltaic device (device actual). 22).

(Example 23) Electron beam (EB) vacuum evaporation method, DC magnetron sputtering method, and μ
The photovoltaic device of the present invention was manufactured by the W glow discharge decomposition method.

Using the apparatus shown in FIG.
B) A 450 nm thick AlSi light reflecting layer containing a nitrogen atom was formed on a stainless steel substrate by vacuum evaporation in the same manner as in Experimental Example 2-3, and zinc oxide (ZnO) was formed thereon by DC sputtering. Was formed. Next, in the same manner as in Example 17, a non-single-crystal silicon-based semiconductor layer was laminated on the light reflection increasing layer, and then a transparent electrode and a current collecting electrode were laminated to produce a photovoltaic device (device actual). 22).

(Example 24) Electron beam (EB) vacuum evaporation method, DC magnetron sputtering method, and μ
The photovoltaic device of the present invention was manufactured by the W glow discharge decomposition method.

Using the apparatus shown in FIG.
B) By vacuum evaporation, an alkali metal atom (Li, Na, K,
An AlSi light reflection layer having a layer thickness of 450 nm containing (Rb, Cs) was formed, and a light reflection enhancement layer made of zinc oxide (ZnO) was formed thereon by DC sputtering. Next, in the same manner as in Example 17, a non-single-crystal silicon-based semiconductor layer was laminated on the light reflection increasing layer, and then a transparent electrode and a current collecting electrode were laminated to produce a photovoltaic device (device actual). 24-
1 to 24-5).

Comparative Example 5 Using the apparatus shown in FIG. 12, a 450 μm thick AlSi light reflecting layer containing no oxygen atoms was formed on a stainless steel substrate, and a 1 μm light reflecting increase made of zinc oxide (ZnO) was formed thereon. Layers were made. Others are Example 21
A photovoltaic element was produced in the same manner as in (1) (element ratio 5).

In order to demonstrate the effect of the present invention on the solar cell characteristics of the photovoltaic elements manufactured in Examples 21 to 24 and Comparative Example 5, the same evaluation test as in Example 1 was performed. Table 17 shows the results.

As is clear from Table 17, Examples 21 to 21
The photovoltaic element No. 24 was found to have significantly improved initial properties, durability, and environmental resistance compared to the element of Comparative Example 5.

Examples 25 to 28 and Comparative Example 6 (Example 25) A photovoltaic device of the present invention was manufactured by a DC magnetron sputtering method and a μW glow discharge decomposition method.

[0258] In the manufacturing apparatus of the DC magnetron sputtering method shown in FIG.
Under the same conditions as in Example 1 except that the temperature of Sample No. 2 was maintained at 350 ° C., a light reflecting layer containing oxygen atoms having a texture structure was formed on the substrate 802 to a thickness of 450 mm. Next, as in Example 1, a light reflection increasing layer (Zn) having a thickness of 1 μm was formed on the light reflection layer.
O) is deposited, and the μ shown in FIG.
A non-single-crystal silicon-based semiconductor layer, a transparent electrode, and a current collecting electrode were stacked on the light reflection increasing layer by a manufacturing apparatus based on the W glow discharge decomposition method, to produce a photovoltaic device (actual element 25).

Example 26 A photovoltaic device according to the present invention was manufactured by DC magnetron sputtering and μW glow discharge decomposition.

[0260] In the manufacturing apparatus of the DC magnetron sputtering method shown in FIG.
Under the same conditions as in Example 2 except that the temperature of Sample No. 2 was maintained at 350 ° C., a light reflecting layer containing carbon atoms having a texture structure was formed on the substrate 802 at 450 mm. Next, as in Example 1, a light reflection increasing layer (Zn) having a thickness of 1 μm was formed on the light reflection layer.
O) is deposited, and the μ shown in FIG.
A non-single-crystal silicon-based semiconductor layer, a transparent electrode, and a current collecting electrode were stacked on the light reflection increasing layer by a manufacturing apparatus based on the W glow discharge decomposition method to produce a photovoltaic element (element 26).

(Example 27) A photovoltaic device of the present invention was manufactured by a DC magnetron sputtering method and a μW glow discharge decomposition method.

With the DC magnetron sputtering apparatus shown in FIG.
A light reflecting layer containing nitrogen atoms having a texture structure of 450 mm was formed on the substrate 802 under the same conditions as in Example 3 except that the temperature of Step 2 was maintained at 350 ° C. Next, as in Example 1, a light reflection increasing layer (Zn) having a thickness of 1 μm was formed on the light reflection layer.
O) is deposited, and the μ shown in FIG.
A non-single-crystal silicon-based semiconductor layer, a transparent electrode, and a current collecting electrode were stacked on the light reflection increasing layer by a manufacturing apparatus based on the W glow discharge decomposition method, to produce a photovoltaic element (element 27).

(Example 28) A photovoltaic device of the present invention was manufactured by a DC magnetron sputtering method and a μW glow discharge decomposition method.

[0264] In the manufacturing apparatus of the DC magnetron sputtering method shown in FIG.
A light reflecting layer containing a textured alkali metal atom (Li, Na, K, Rb, Cs) was formed on the substrate 802 under the same conditions as in Example 4 except that the temperature of Example 2 was maintained at 350 ° C.
50 mm was produced. Next, in the same manner as in Example 1, a light reflection increasing layer (ZnO) having a thickness of 1 μm is deposited on the light reflection layer, and is further formed on the light reflection increasing layer by a manufacturing apparatus using a μW glow discharge decomposition method shown in FIG. Then, a non-single-crystal silicon-based semiconductor layer, a transparent electrode, and a current collecting electrode were stacked on the light reflection increasing layer to produce photovoltaic elements (element examples 28-1 to 28-5).

[0265] (Comparative Example 6) deposition chamber 802, O ₂ / Ar
A 450 nm light-reflective layer having a textured structure and containing no oxygen atoms was formed on a substrate 802 under the same conditions as in Example 25 except that Ar gas was introduced instead of gas. afterwards,
A photovoltaic element was produced in the same manner as in Example 1 (element ratio: 6).

In order to demonstrate the effect of the present invention on the solar cell characteristics of the photovoltaic elements manufactured in Examples 25 to 28 and Comparative Example 6, the same evaluation test as in Example 1 was performed. The results are shown in Table 18.

As is clear from Table 18, Examples 25 to
It was found that the photovoltaic element No. 28 had significantly improved initial properties, durability and environmental resistance as compared with the element of Comparative Example 6.

(Example 29) A photovoltaic device of the present invention was manufactured by a DC magnetron sputtering method and a microwave (μW) glow discharge method.

First, a light reflecting layer of AlSi containing oxygen atoms and carbon atoms was formed on a stainless steel substrate by a DC magnetron sputtering apparatus shown in FIG.

In the figure, reference numeral 802 denotes a 50 mm square and a thickness of 0.2 m.
m, mirror-finished stainless steel (SUS43
0), with acetone (CH ₃ OCH ₃ ) for 10 minutes,
Ultrasonic cleaning was performed for 10 minutes with isopropanol (CH ₃ CHOHCH ₃ ), and hot air drying was performed at 80 ° C. for 30 minutes.

In the drawing, reference numeral 804 denotes an aluminum-silicon alloy (AlSi) target having a purity of 99.999%, which is insulated from the deposition chamber 801 by an insulating support 805. In the figure, reference numerals 810, 812, 814, and 816 denote gas introduction valves, respectively, which are not shown in the drawings. Argon (Ar) gas cylinder (purity: 99.9999%) and nitrogen (N ₂ / Ar) diluted to 50 ppm with argon (Ar) gas. ) Gas cylinder, methane (CH ₄ / Ar) gas cylinder diluted to 50 ppm with argon (Ar) gas, argon (Ar)
It is connected to an oxygen (O ₂ / Ar) gas cylinder diluted to 50 ppm with gas.

First, the inside of the deposition chamber 801 is evacuated by a vacuum pump (not shown), and the reading of the vacuum gauge 808 is about 1 × 10 ⁻⁶ T.
orr, the gas introduction valves 810, 81
4, 816 is gradually opened, and the Ar gas flow rate is 10 scc.
m, the mass flow controllers 811, 815, and 817 are adjusted so that the CH ₄ / Ar gas flow rate is ₂ sccm and the O ₂ / Ar gas flow rate is ₂ sccm, and the pressure in the deposition chamber 801 is 6 mTorr. Vacuum gauge 8
While watching 08, conductance valve (pattern fly type)
The opening 809 was adjusted. Thereafter, the voltage of the DC power supply 806 was set to -400 V, DC power was introduced to the target 804, and a DC glow discharge was generated. After 5 minutes, the shutter 807 is opened, and the Al
Production of a light reflection layer of Si was started, and when a light reflection layer having a thickness of 450 nm was produced, a shutter 807 was closed and DC
The output of the power supply 806 was turned off to stop DC glow discharge. Next, the gas introduction valves 814 and 816 are closed, and the deposition chamber 8 is closed.
The flow of CH ₄ / Ar gas and O ₂ / Ar gas into 01 was stopped, and the mass flow controller 811 was adjusted so that the flow rate of Ar gas became 100 sccm.

Next, the conductance valve 809 was closed, the deposition chamber 801 was gradually leaked, and the fabrication of the AlSi light reflecting layer containing oxygen atoms and carbon atoms was completed.

Further, under the same manufacturing conditions as in Example 1, the light reflecting layer was 1 μm thick using the magnetron sputtering apparatus shown in FIG.
m. Next, the μW shown in FIG.
A non-single-crystal silicon-based semiconductor layer was laminated by a glow discharge method, and a transparent electrode and a current collecting electrode were laminated by the same method and under the same conditions as in Example 1 to produce a photovoltaic element (Element Example 2).
9). Table 19 shows the above manufacturing conditions.

(Comparative Example 7) A conventional photovoltaic element was manufactured in the same manner as in Comparative Example 1.

First, an AlSi light reflecting layer containing no carbon atoms and no oxygen atoms was formed on a substrate by a DC magnetron sputtering apparatus shown in FIG.
nm.

Next, under the same manufacturing conditions as in Example 29, a light 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 on the light reflecting layer to form a photovoltaic element. Was prepared (element ratio 7).

In order to demonstrate the effect of the present invention on the solar cell characteristics of the photovoltaic elements manufactured in Example 29 and Comparative Example 7, the same evaluation test as in Example 1 was performed.

In contrast to (element ratio 7), (element actual 29) is
1.07 times in photoelectric conversion efficiency, 1.09 times in adhesion test,
After the environmental test, it was found that the photovoltaic device using the light reflecting layer containing oxygen atoms and carbon atoms of the present example has characteristics superior to those of the conventional device. Has been demonstrated.

(Example 30) A photovoltaic device of the present invention was manufactured by a DC magnetron sputtering method and a microwave (μW) glow discharge method.

First, a light reflecting layer of AlSi containing oxygen, carbon and nitrogen atoms was formed on a stainless steel substrate by a DC magnetron sputtering apparatus shown in FIG.

In the drawing, reference numeral 802 denotes a 50 mm square and a thickness of 0.2 m.
m, mirror-finished stainless steel (SUS43
0), with acetone (CH ₃ OCH ₃ ) for 10 minutes,
Ultrasonic cleaning was performed for 10 minutes with isopropanol (CH ₃ CHOHCH ₃ ), and hot air drying was performed at 80 ° C. for 30 minutes.

In the drawing, reference numeral 804 denotes an aluminum-silicon alloy (AlSi) target having a purity of 99.999%, which is insulated from the deposition chamber 801 by an insulating support 805. In the figure, reference numerals 810, 812, 814, and 816 denote gas introduction valves, respectively, which are not shown in the drawings. Argon (Ar) gas cylinder (purity: 99.9999%) and nitrogen (N ₂ / Ar) diluted to 50 ppm with argon (Ar) gas. ) Gas cylinder, methane (CH ₄ / Ar) gas cylinder diluted to 50 ppm with argon (Ar) gas, argon (Ar)
It is connected to an oxygen (O ₂ / Ar) gas cylinder diluted to 50 ppm with gas.

First, the inside of the deposition chamber 801 is evacuated by a vacuum pump (not shown), and the vacuum gauge 808 reads about 1 × 10 ⁻⁶ T.
orr, the gas introduction valves 810, 81
2, 814 and 816 are gradually opened until the Ar gas flow rate becomes 1
0 sccm, N ₂ / Ar gas flow rate is ₂ sccm, CH ₄
/ Ar gas flow rate is ₂ sccm, O ₂ / Ar gas flow rate is 2
Each of the mass flow controllers 811, 813, 815, and 817 was adjusted so as to have a sccm.
01 and a vacuum gauge 80
While watching 8, conductance valve (putterfly type) 8
09 opening was adjusted. Thereafter, the voltage of the DC power supply 806 was set to -400 V, DC power was introduced to the target 804, and a DC glow discharge was generated. After 5 minutes have elapsed, the shutter 807 is opened and the AlS
Production of the light reflection layer of i was started. When a light reflection layer having a thickness of 450 nm was produced, the shutter 807 was closed, the output of the DC power supply 806 was turned off, and the DC glow discharge was stopped. Next, the gas introduction valves 812, 814, and 816 are closed,
The flow of N ₂ / Ar gas, CH ₄ / Ar gas, O ₂ / Ar gas into the deposition chamber 801 is stopped, and the flow rate of the Ar gas becomes 1
Mass flow controller 81 so that it becomes 00 sccm
1 was adjusted.

Next, the conductance valve 809 was closed, the deposition chamber 801 was gradually leaked, and the fabrication of the AlSi light reflecting layer containing oxygen, carbon and nitrogen atoms was completed.

Further, under the same manufacturing conditions as in Example 29, a light reflection increasing layer was manufactured using the magnetron sputtering apparatus shown in FIG. Next, a non-single-crystal silicon-based semiconductor layer is laminated by the μW glow discharge method shown in FIG. 13 under the same method and conditions as in Example 29, and the transparent electrode and the current collecting electrode are formed under the same method and conditions as in Example 29. The photovoltaic element was manufactured by stacking (element 30).

In order to demonstrate the effect of the present invention on the solar cell characteristics of the photovoltaic device manufactured in Example 30, the same evaluation test as in Example 1 was performed, and the photovoltaic device of Comparative Example 7 (element ratio) 7).

In contrast to (element ratio 7), (element actual 30) is
1.09 times in photoelectric conversion efficiency, 1.11 times in adhesion test,
1.13 times larger after the environmental test, the oxygen atom of this example,
It was found that a photovoltaic device using a light reflecting layer containing carbon atoms and nitrogen atoms had better characteristics than a conventional device, and the effect of the present invention was demonstrated.

[0289]

As described above, the photovoltaic device of the present invention comprises AlSi as a main constituent element and contains oxygen, nitrogen, carbon atom or alkali metal atom (Li, Na, K, Rb, Cb).
By using a light reflecting layer containing at least one of s), the short-circuit current is further increased as compared with the conventional photovoltaic element, the series resistance is reduced, and the conversion efficiency is improved.

Further, according to the present invention, the adhesion between the conductive substrate and the light reflection layer and the adhesion between the light reflection layer and the reflection increasing layer are improved, and the environmental resistance and durability of the photovoltaic element are improved.

Further, according to the present invention, it is possible to prevent the metal of the light reflection layer from diffusing into the reflection enhancement layer and the non-single-crystal semiconductor layer,
It is possible to provide a photovoltaic element having high durability.

In addition, according to the present invention, after the light reflecting layer is deposited, the substrate temperature change during the deposition of the reflection enhancing layer and the non-single-crystal semiconductor layer and the like, and the photovoltaic element is used in a high-temperature, high-humidity repeated environment. Accordingly, the progress of crystal growth can be prevented, and a photovoltaic device having stable device characteristics over time can be provided.

Further, according to the present invention, it is possible to provide a photovoltaic element which can be mass-produced with a high yield.

[0294]

[Table 1]

[0295]

[Table 2]

[0296]

[Table 3]

[0297]

[Table 4]

[0298]

[Table 5]

[0299]

[Table 6]

[0300]

[Table 7]

[0301]

[Table 8]

[0302]

[Table 9]

[0303]

[Table 10]

[0304]

[Table 11]

[0305]

[Table 12-1]

[0306]

[Table 12-2]

[0307]

[Table 12-3]

[0308]

[Table 12-4]

[0309]

[Table 12-5]

[0310]

[Table 13]

[0311]

[Table 14]

[0312]

[Table 15]

[0313]

[Table 16]

[0314]

[Table 17]

[0315]

[Table 18]

[0316]

[Table 19]

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing one configuration example of a photovoltaic element of the present invention.

FIG. 2 is a schematic diagram illustrating another configuration example of the photovoltaic device of the present invention.

FIG. 3 is a schematic diagram showing another configuration example of the photovoltaic element of the present invention.

FIG. 4 is an example of an apparatus for producing a transparent electrode constituting the photovoltaic device of the present invention, and is a schematic diagram of DC magnetron sputtering standing.

FIG. 5 is a graph showing the crystal grain size distribution of AlSi in the light reflecting layers produced in Experimental Examples 1-1 to 1-4 and Comparative Experimental Example 1.

FIG. 6 is a schematic diagram illustrating an example of an apparatus for performing a bending test.

FIG. 7 is a graph showing a change in the distribution of the crystal grain size of AlSi before and after annealing for the light reflecting layers produced in Experimental Examples 1-1 to 1-4 and Comparative Experimental Example 1.

FIG. 8 is an example of an apparatus for producing a light reflection layer and a light reflection increasing layer constituting the photovoltaic element of the present invention, and is a schematic view of a production apparatus by a DC magnetron sputtering method.

FIG. 9 is an example of an apparatus for producing a light reflection layer constituting a photovoltaic element of the present invention, and is a schematic view of a production apparatus by a vacuum evaporation method.

FIG. 10 is a graph showing the crystal grain size distribution of AlSi in the light reflecting layers produced in Experimental Examples 2-1 to 2-4 and Comparative Experimental Example 2.

FIG. 11 is a graph showing changes in the distribution of AlSi crystal grain diameters before and after annealing for the light reflecting layers produced in Experimental Examples 2-1 to 2-4 and Comparative Experimental Example 2.

FIG. 12 is an example of an apparatus for continuously producing a light reflection layer and a light reflection increasing layer constituting the photovoltaic device of the present invention, and is a schematic view of a production apparatus using a DC magnetron sputtering method and a vacuum evaporation method. It is.

FIG. 13 is an example of an apparatus for manufacturing a non-single-crystal silicon-based semiconductor layer included in the photovoltaic device of the present invention,
It is a schematic diagram of a manufacturing apparatus by a microwave glow discharge method.

FIG. 14 is an example of an apparatus for manufacturing a non-single-crystal silicon-based semiconductor layer included in the photovoltaic device of the present invention,
It is a schematic diagram of a manufacturing apparatus by an RF glow discharge method.

[Explanation of symbols]

101, 301 conductive substrate 102, 202 light reflection layer 103, 203, 303 light reflection enhancement layer 104, 204a, 204b, 304a, 304b n
-Type (or p-type) non-single-crystal silicon semiconductor layers 105, 205a, 205b, 305a, 305bi
-Type non-single-crystal silicon-based semiconductor layers 106, 206a, 206b, 306a, 306bp
Type layer (or n-type) non-single-crystal silicon-based semiconductor layer 107, 207, 307 Transparent electrode 108, 208, 308 Current collecting electrode 109, 209, 309 Light 201 Transparent substrate 210 Conductive layer (or / and protective layer) 302 Texture Light reflecting layer 401, 801 Deposition chamber 402, 802 Substrate 403, 803 Heater 404, 804, 818 Target 405, 805 Insulating support 406, 806, 820 DC power supply 407, 807, 821 Shutter 408, 808 Vacuum gauge 409, 809, conductance valve 410, 412, 414, 416, 810, 81281
4,816 Gas introduction valve 411,413,415,417,811,813,8
15,817 Mass flow controller 601 Substrate 602 Substrate bending rod 603 Air cylinder 901 Deposition chamber 902 Substrate 903 Heater 904 Evaporation 905 Electron gun 906 High voltage power supply 907 Shutter 908 Vacuum gauge 909 Conductance valve 910, 912, 914, 916 Gas introduction valve 911 , 913, 915, 917 Mass flow controller 1201 Deposition chamber 1202 Substrate 1203 Heater 1204 Evaporation source 1205 Electron gun 1206 High voltage power supply 1207, 1221 Shutter 1208 Vacuum gauge 1209 Conductance valve 1210, 1212, 1214, 1216 Gas introduction valve 1211, 1213 1215, 1217 Mass flow controller 1218 Target 1219 Insulating support 12 0 DC power supply 1301 μW Deposition chamber of film forming apparatus by glow discharge decomposition method 1302 Dielectric window 1303, 1403 Gas introduction pipe 1304, 1404 Substrate 1305, 1405 Heater 1306, 1406 Vacuum gauge 1307, 1407 Conductance valve 1308, 1408 Auxiliary valve 1309, 1409 Leak valve 1310 Wave guide 1311 Bias power supply 1312 Bias rod 1320 Source gas supply device 1321 to 1326 Mass flow controller 1331 to 1386 Gas inflow valve 1341 to 1346 Gas outflow valve 1351 to 1356 Source gas cylinder valve 1361 to 1366 Pressure regulator 1371 to 1376 Source gas cylinder 1401 Deposition chamber of film forming apparatus by RF glow discharge decomposition method 1402 Cathode 1412 FR Tick ring box.

Continued on the front page (72) Inventor Masahiko Tongaki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Toshimitsu Kariya 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Takakazu Matsuda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Naoto Okada 3-30-2, Shimomaruko 3-chome, Ota-ku, Tokyo Canon Inc. (72) Inventor Ryuji Kondo 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Tomonori Nishimoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yutaka Nishio 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-58-159383 (JP, A) JP-A-59-220977 (JP, A) JP-A-2-9176 ( JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) H01L 31/04

Claims (4)

(57) [Claims] 1. A light reflecting layer, a light reflection increasing layer, an n-type layer, an i-type layer and a p-type layer made of a non-single-crystal semiconductor material containing at least silicon atoms, and a transparent electrode are laminated on a conductive substrate. In the photovoltaic element configured as above, the light reflection layer has Al and Si atoms as main constituent elements, and contains at least one of an oxygen atom, a nitrogen atom, a carbon atom, and an alkali metal atom. Characteristic photovoltaic element. 2. The method according to claim 1, wherein the alkali metal atom is Li, Na,
The photovoltaic device according to claim 1, wherein the photovoltaic device is at least one selected from the group consisting of K, Rb, and Cs. 3. The photovoltaic device according to claim 1, wherein the total amount of oxygen atoms, nitrogen atoms and carbon atoms contained in the light reflecting layer is 0.1 to 1000 ppm. 4. The photovoltaic device according to claim 1, wherein the total amount of alkali metal atoms contained in the light reflecting layer is 2 to 100 ppm.