JP2829654B2 - Photovoltaic element - Google Patents

Description

Description: TECHNICAL FIELD [0001] The present invention relates to a photovoltaic element improved as a solar cell suitable for a power supply system for consumer appliances and a power supply system using solar power. More specifically, the present invention relates to a photovoltaic device using a pin heterojunction and having high photoelectric conversion efficiency particularly for short wavelength light.

[Description of Prior Art]

Conventionally, as a photovoltaic element for a power supply for consumer equipment or a solar cell for photovoltaic power generation, it is formed by ion-implanting or thermally diffusing impurities into a single crystal substrate such as silicon (Si) or gallium arsenide (GaAs). Alternatively, a photovoltaic element using a pn junction formed by epitaxially growing a layer doped with an impurity on such a single crystal substrate has been proposed. However, since these photovoltaic elements use a single crystal substrate as described above as a substrate, the manufacturing cost is extremely high, and the reduction is technically difficult. The fact is that it has not been reached.

By the way, in recent years, glass, metal,
Amorphous silicon (hereinafter, referred to as glow discharge decomposition method) is mounted on a substrate of inexpensive material such as ceramics and synthetic resin.
It is called "A-Si". ) A photovoltaic element using a pin junction formed by stacking semiconductor deposition films has been proposed.
Although the photoelectric conversion efficiency of the above-mentioned single-crystal pn junction solar cell has not been obtained, it is widely used as a power source for low-cost consumer appliances such as calculators and watches because of its relatively easy manufacturing method and low cost. Is coming.

In this pin-junction type photovoltaic element, the Fermi level of the A-Si semiconductor having excellent photoelectric characteristics is located slightly closer to the conduction band from the center of the band gap, so that the p-type is higher than the n-i junction interface. electric field strength is strong at the i-junction interface,
It is said that making light incident from the p-type semiconductor layer side is advantageous for improving the photoelectric conversion efficiency.

On the other hand, when there are many defects serving as recombination centers in the p-type semiconductor layer, light absorbed in the p-type semiconductor layer hardly contributes to generation of a photocurrent. It is desirable that the semiconductor film be formed of a semiconductor film with a minimum of light absorption and few defects. However, as a semiconductor material used for the p-type semiconductor layer in the pin junction type A-Si photovoltaic element, amorphous silicon carbide having a wide band gap (hereinafter, referred to as "A-SIC").
Alternatively, a microcrystalline silicon (hereinafter, referred to as a bandgap) which is considered to have a small absorption coefficient because the bandgap is a narrow indirect transition type semiconductor material and a small amount of light absorption at a thickness of 100 to 200 mm.
This is referred to as “μC-Si”. ) Are being considered. However, in A-SiC, it is possible to widen the band gap by increasing the composition ratio of carbon atoms in the film. However, when the band gap becomes 2.1 eV or more, the film quality rapidly decreases, so that the solar cell There is naturally a limit to the improvement of the characteristics.

Also in the case of μC-Si, since the band gap is essentially narrow, the amount of light absorption cannot be ignored. In particular, in the case of incident light in which the proportion of short-wavelength light components is large, the amount of absorbed light increases significantly.

Therefore, in order to form a photovoltaic element having higher photoelectric conversion efficiency, if the p-type semiconductor layer side is the light incident side, a p-type semiconductor having a wider band gap, a lower defect density, and an unprecedented characteristic. Type semiconductor materials need to be provided urgently.

In addition, as long as the n-type semiconductor material has a sufficiently wide band gap and a low defect density, a photovoltaic element can be configured with the side on which the n-type semiconductor layer is provided as a light incident side. Further, in a so-called tandem type photovoltaic element formed by laminating pin junction type photovoltaic elements and a triple type photovoltaic element, light having a wavelength component that cannot be absorbed by the upper photovoltaic element is used. In order to allow the p-type semiconductor layer and the n-type semiconductor layer to have a sufficiently wide band gap and a low defect density in order to transmit the No.

Further, the p-type or n-type semiconductor material can be directly deposited on non-single-crystal substrates such as glass, metal, ceramics, and synthetic resin, as well as i-type semiconductor deposited on these non-single-crystal substrates. It must be possible to deposit without adversely affecting the layer.

III-V group compound semiconductor materials have been proposed and evaluated as semiconductor materials having a wide band gap satisfying such requirements. Specifically, Japanese Unexamined Patent Publication No.
It is called "Document 1." ), JP-A-61-6874 (hereinafter, referred to as "Document 2"), JP-A-61-189629 (hereinafter, referred to as "Document 3"), and JP-A-61-189630 (hereinafter, referred to as "Document 2"). 4 ").

However, in Document 1, in a pin heterojunction type amorphous thin film solar cell, a p-type or n-type III-V compound semiconductor layer is formed by a glow discharge decomposition method, and an i-type semiconductor layer is formed of a fluorine-based amorphous. Although made of silicon film,
There is no mention of a crystalline BAs film. In addition, amorphous silicon germanium (A-
There is no mention of SiGe) films.

Document 2 shows that by using a compound semiconductor as a doped layer in a pin junction solar cell that also combines a compound semiconductor film and an amorphous silicon film,
It is intended to improve the photovoltaic characteristics,
In particular, there is no specific disclosure about a BAs film.

Also, none of the documents mentions a tandem or triple photovoltaic device.

Documents 3 and 4 refer to HRCVD (Hydrogen Radical assi
ate CVD) method, when depositing and forming a III-V compound semiconductor film, the content of the film is to be increased dramatically to increase the film deposition rate.
There is no specific disclosure about the s film.

Against this background, a desired photoelectric conversion efficiency, particularly a high efficiency photoelectric conversion efficiency for short-wavelength light, is obtained. As a solar cell for a power supply system using solar power as well as a power supply for consumer appliances. There is a social demand for early provision of a photovoltaic element that is practical and inexpensive and has high reliability.

[Object of the invention]

An object of the present invention is to solve the conventional problems relating to a photovoltaic element constituting a solar cell or the like and to provide a photovoltaic element satisfying the above-mentioned social demands and the like.

Another object of the present invention is to form a good pin junction even when deposited and formed on a substrate of inexpensive materials such as glass, metal, ceramics, and synthetic resin that are non-single-crystal substrates,
It is an object of the present invention to provide a photovoltaic element capable of effectively converting incident light, particularly its short wavelength light component, into a photocurrent.

[Summary of the invention, effects]

Means for Solving the Problems The present inventors have overcome the conventional problems of a wide band gap semiconductor deposited film suitable for use as a window layer of a photovoltaic element such as a solar cell, and have intensively studied to achieve the object of the present invention. , BAs film, a polycrystalline semiconductor deposited film (hereinafter, referred to as a “BAs: H (F) film”) having an average crystal grain size in a specific range, a specific amount of hydrogen atoms, and optionally containing fluorine atoms. ), The polycrystalline semiconductor deposited film can be deposited in a desired state on the surface of a substrate made of glass, metal, ceramics, synthetic resin, or the like. It has very few defects, can introduce a required amount of p-type or n-type dopant into a desired state, has high doping efficiency, and has good p-type or p-type dopant.
The fact that the film was a crystalline film having a conductivity type of n-type or n-type was obtained from the experimental results described below.

According to the present invention, the present inventors have further studied based on the above findings, and have found that a crystalline film having the above-mentioned excellent characteristics can be formed into a p-type and / or n-type semiconductor of a photovoltaic device using a pin junction. It has been applied to layers and completed.

 The present invention includes the following two photovoltaic elements.

(1) A photovoltaic device having a junction structure of a p-type semiconductor layer, an i-type semiconductor layer, and an n-type semiconductor layer, wherein at least one of the p-type semiconductor layer and the n-type semiconductor layer among the semiconductor layers One of which is a hydrogen atom and / or a fluorine atom,
the average crystal grain size including a p-type or n-type valence electron controlling atom is
A polycrystalline BAs thin film having a thickness of 50 to 800 °, wherein the content of the hydrogen atoms is 0.5 to 6 atomic%, and the i-type semiconductor layer is formed of a non-single-crystal silicon semiconductor containing a hydrogen atom and / or a fluorine atom. (2) a photovoltaic element having a junction structure of a p-type semiconductor layer, an i-type semiconductor layer, and an n-type semiconductor layer, wherein at least one of the semiconductor layers Either the p-type semiconductor layer or the n-type semiconductor layer is a hydrogen atom and / or a fluorine atom,
the average crystal grain size including a p-type or n-type valence electron controlling atom is
A polycrystalline BAs thin film having a thickness of 50 to 800 °, wherein the content of the hydrogen atoms is 0.5 to 6 atomic%, and the i-type semiconductor layer is formed of germanium atoms and / or carbon atoms, hydrogen atoms and / or fluorine atoms, A photovoltaic device comprising a non-single-crystal silicon alloy-based semiconductor containing:

The results of experiments performed by the present inventors will be described in detail below.

[Experiment]

Experiment A. BAs with hydrogen atoms and optionally fluorine atoms:
Investigation of H (F) film formation method (1) HRCVD method In this method, a raw material gas containing B atoms, a raw material gas containing As atoms, and a raw material gas containing hydrogen gas (H ₂ ) and fluorine atoms The gas generated by activating gas alone or in a mixed state in an activation space different from the film formation space, and
A precursor containing atoms, a precursor containing As atoms, and hydrogen radicals and fluorine radicals are introduced into the film formation space and chemically reacted with each other to form BAs on the substrate heated and held in the film formation space. : H (F) to form a polycrystalline semiconductor deposited film.

This will be described specifically with reference to a schematic diagram of the deposited film forming apparatus shown in FIG.

201 is a film forming chamber having means for performing the method of the present invention, the substrate 203 is held on a substrate holding cassette 202,
It can move on the substrate transfer jig 206. A thermocouple 204 is used for monitoring when the temperature of the substrate 203 is heated and held by the heater 205. Reference numeral 212 denotes a load lock chamber, which has a built-in substrate transfer jig 206 and can vacuum transfer the substrate through a gate valve 207. Reference numeral 222 denotes a film formation chamber which is effectively used when a semiconductor layer formed of a material different from that formed in the film formation chamber 201 is stacked, and is similar to that provided in the film formation chamber 201. Or other different film forming means (not shown). 208,209,210
Is an activation chamber for the source gas for film formation, and the gas supply pipe 21
The source gas introduced from 4,215,216 is activated by electricity, heat, light energy, etc. supplied from the excitation energy generators 211,212,213, and the precursor, hydrogen radicals, etc. generated here pass through the transport pipes 217,218,219 to form a film forming chamber. When introduced into the substrate 201, a chemical interaction occurs, and a semiconductor film having desired characteristics is formed on the substrate 203. Reference numeral 221 denotes an exhaust pump, which controls the pressure in the film forming chamber 201 monitored by the pressure gauge 223 by adjusting the opening of the throttle valve 220.

First, a Corning # 7059 glass substrate 203 having a size of 2 inches × 2 inches and a thickness of 0.8 mm was set in a substrate holding cassette 202, and BAs: H (F) film sample No. 1 was formed under the film forming conditions shown in Table 1.
~ 10 were prepared.

A part of the obtained sample was cut out and SIMS (CAMEA ims
-3f) was used to determine the content of hydrogen and fluorine atoms in the deposited film using XMA (X-ray microanalyzer EPM manufactured by Shimadzu Corporation).
-810Q) to analyze the distribution and elemental composition of B and As atoms in the deposited film, and use an X-ray diffractometer (Rigaku Denki RADI
IB), the crystal orientation and the average crystal grain size were measured. Table 2 summarizes the measurement results.

From these results, in the present method, it is possible to control the content of hydrogen atoms and / or the content of fluorine atoms in the deposited film and the average crystal grain size by changing the amount of H ₂ gas introduced into the activation chamber 209. I understood. H ₂ gas introduction
In Samples Nos. 1 and 2 prepared at 0 sccm and 0.2 sccm, no hydrogen radicals were supplied to the reaction system or the amount was small, so that the amount of contained hydrogen atoms was small and the amount of fluorine atoms was large. And the distribution of As atoms are also localized,
The crystal structure was also a structure with no orientation (random),
In Samples Nos. 3 to 7, the composition ratio of B atoms and As atoms became to satisfy the stoichiometric ratio with an increase in the amount of H ₂ gas introduced, a specific crystal orientation occurred, and the average crystal grain size also increased. There was a tendency to increase. Further, since the supply amount of hydrogen radicals into the reaction system in a sample No.8~10 manufactured by further increasing the H ₂ gas introduction rate is excessive, the decrease in average grain size by etching of the deposited film and There was a decreasing trend of the hydrogen atom content. Thus, it became clear that the supply amount of the hydrogen radical to the reaction system plays an important role in forming the deposited film.

According to the experiment performed in parallel with this experiment, the substrate temperature, pressure, microwave input power, dilution gas (He) flow ratio, distance between the gas outlet of the transport pipe and the substrate, and the combination of source gas Although it was possible to control the hydrogen atom content and the fluorine atom content, and further the average crystal grain size by changing the parameters such as the change of H, the controllability was inferior to the controllability by changing the H ₂ gas introduction amount described above. I was

(2) Reactive sputtering method In this method, a substrate is placed in a film formation chamber, a cathode electrode is placed at a position facing the substrate and leaving a predetermined space between the substrate and the substrate, and a surface of the cathode electrode is placed on the surface of the cathode electrode. Ar gas and H ₂ gas and / or F ₂ gas are placed in a film forming chamber in which a non-doped polycrystalline or single crystal BAs wafer as a target or a polycrystalline or single crystal BAs wafer in which H atoms and / or F atoms are dosed by ion implantation is arranged. ₂ , HF gas is introduced, a high-frequency voltage is applied to the cathode electrode, the gas plasma atmosphere is formed in the space, the polycrystalline BAs wafer or the like as a target is sputtered, and B atoms and As atoms jumping out of the target. And atomic hydrogen and / or fluorine present in the gas plasma are chemically reacted in a space near the surface of the substrate to form BAs: H (F). A polycrystalline semiconductor deposited film formed on a substrate which is heated and maintained.

This will be described specifically with reference to a schematic diagram of the deposited film forming apparatus shown in FIG.

Reference numeral 301 denotes a film forming chamber having means for performing the method of the present invention, and a substrate 303 is held on a substrate holding cassette 302;
It can move on the substrate transfer jig 306. A thermocouple 304 is used for monitoring when the temperature of the substrate 303 is heated and held by the heater 305. Reference numeral 313 denotes a load lock chamber, which has a built-in substrate transfer jig 306 and can vacuum transfer the substrate through a gate valve 307.

Reference numeral 316 denotes a film formation chamber which is effectively used when a semiconductor layer formed of a material different from that formed in the film formation chamber 301 is stacked, and is similar to that provided in the film formation chamber 301. Or other different film forming means (not shown).

Reference numeral 312 denotes a cathode electrode on which, for example, a polycrystalline BAs wafer is bonded as a target 317. Further, high-frequency power is supplied to the cathode electrode 312 from a high-frequency power supply 310 via a matching box 311, and the gas introduction pipe 3
The sputtering gas such as Ar, H ₂ and F ₂ introduced from 08 is turned into plasma. B atoms and As atoms are sputtered from the target 317 by the ion species generated in the plasma, and atomic hydrogen and / or
Alternatively, a chemical interaction occurs with fluorine, and a BAs: H (F) film, which is a polycrystalline semiconductor film having desired characteristics, is formed over the substrate 303. An exhaust pump 315 controls the pressure in the film forming chamber 301 monitored by the pressure gauge 309 by adjusting the opening of the throttle valve 314.

First, a Corning # 7059 glass substrate 303 having a size of 2 inches × 2 inches and a thickness of 0.8 mm was set in the substrate holding cassette 302, and the BAs: H (F) film sample No.
11 to 20 were prepared. A part of the obtained sample was cut out, and the results of the same evaluation and measurement as performed by the method (1) described above are shown in Table 4.

From these results, in this method, by changing the amount of H ₂ gas and / or HF gas introduced into the film formation chamber 301, the hydrogen atom content and / or the fluorine atom content in the deposited film, and furthermore, the average It was found that the crystal grain size can also be controlled. Sample prepared without introducing H ₂ gas and HF gas
In No. 11 and sample No. 12 prepared by introducing 1 sccm of H ₂ gas and 1 sccm of HF gas, hydrogen radicals and fluorine radicals are not present in the plasma, or both are present in a very small amount, Although the composition ratio between B atoms and As atoms did not satisfy the stoichiometric ratio, the distribution state was somewhat non-uniform, the crystal orientation was random, and the average crystal grain size was small. In sample Nos. 13 to 18, H ₂
As the introduction amount of gas and HF gas increases, the composition ratio of B atoms and As atoms satisfies the stoichiometric ratio, the distribution state is improved, the average crystal grain size increases, and appropriate amounts of hydrogen atoms and fluorine atoms Was found to be contained. In addition, with HF gas
The hydrogen radicals and fluorine radicals present in the plasma becomes excessive in the samples No.19,20 which both increased the flow rate of H ₂ gas, reducing and hydrogen atom content of the grain size, the fluorine atom content There was an increasing trend.

According to the experiment performed in parallel with this experiment, the hydrogen atom content and the slight amount were changed due to changes in parameters such as substrate temperature, pressure, high-frequency power, sputter gas (Ar) flow rate, distance between target and substrate, and target material. Although the control of the fluorine atom content and the average crystal grain size were possible, the controllability was inferior to the controllability by the change of the introduction amount of the H ₂ gas and / or the F ₂ gas and the HF gas described above.

From the above, it became clear that the amounts of hydrogen radicals and fluorine radicals existing in the reaction system play an important role in forming the deposited film.

(3) Plasma CVD Method In this method, a source gas containing B atoms, a source gas containing As atoms, a H ₂ gas and / or a H ₂ gas are mixed so as to be mixed in a reaction space of a film formation chamber in which a substrate is placed. Alternatively, HF gas or F ₂ gas is introduced, high-frequency power is applied to a cathode electrode installed in the film formation chamber to form plasma by glow discharge in the reaction space, and the gas introduced therein is decomposed. , Polymerization, radicalization, ionization, etc. to cause a chemical interaction, on the substrate heated and held in the film forming chamber
A polycrystalline semiconductor deposited film composed of BAs: H (F) is formed.

This will be specifically described with reference to a schematic diagram of the deposited film forming apparatus shown in FIG.

Reference numeral 401 denotes a film forming chamber having means for performing the method of the present invention, and a substrate 403 is held on a substrate holding cassette 402;
It can move on the substrate transfer jig 406. A thermocouple 404 is used for monitoring when the temperature of the substrate 403 is heated and held by the heater 405. Reference numeral 413 denotes a load lock chamber, which has a built-in substrate transfer jig 406 and can vacuum transfer the substrate via a gate valve 407. Reference numeral 416 denotes a film formation chamber which is effectively used when a semiconductor layer formed using a material different from that formed in the film formation chamber 401 is stacked, and is similar to that provided in the film formation chamber 401. Or other different film forming means (not shown).

A cathode electrode 412 is supplied with high-frequency power from a high-frequency power supply 410 via a matching box 411, and the source gas introduced from the gas introduction pipes 408, 409 is turned into plasma. Precursors generated in the plasma, hydrogen radicals,
Fluorine radicals, various ions, and the like reach the substrate 403 while undergoing a chemical interaction to form a BAs: H (F) film, which is a semiconductor film having desired characteristics. Reference numeral 415 denotes an exhaust pump, which controls the pressure in the film forming chamber 401 monitored by the pressure gauge 417 by adjusting the opening of the throttle valve 414.

First, a Corning # 7059 glass substrate 403 having a size of 2 inches × 2 inches and a thickness of 0.8 mm was set in a substrate holding cassette 402, and BAs: H (F) film sample No. 21 was formed under the film forming conditions shown in Table 5.
~ 30 were made.

The source gases (A), (B) and (C) were introduced into the film forming chamber 401 from a cylinder (not shown) via the gas introduction pipe 408 or 409.

A part of the obtained sample was cut out and measured and evaluated in the same manner as in the above-mentioned method (1). The results are shown in Table 6.

From these results, in the present method, the H ₂ gas and / or HF as the source gas (C) to the film formation chamber 401 changes the gas introduction amount to change the hydrogen atom content in the deposited film and / or It was found that the content of fluorine atoms and also the average crystal grain size could be controlled. In Sample Nos. 21 to 23, the H ₂ gas and the HF gas are not introduced, or the flow rate is small even if at least one is introduced, so that the deposited film formed has an amorphous structure. In addition, B atoms and As are affected by the residual -CH ₃ (methyl group).
At the same time that the distribution of atoms is non-uniform, the hydrogen atom content due to -CH ₃ groups is increasing. Sample No.2
In 4 to 28, the crystal orientation appears as the H ₂ gas and / or HF gas increases, the composition ratio of B atoms and As atoms satisfies the stoichiometric ratio, the distribution state is improved, and the average crystal grain size is improved. The diameter also increased, and a tendency was observed to contain appropriate amounts of hydrogen atoms and fluorine atoms. In addition, samples with increased H ₂ gas flow rate
In Nos. 29 and 30, the tendency for the average crystal grain size to decrease was observed due to the excess of hydrogen radicals present in the plasma.

According to the experiment performed in parallel with this experiment, slight changes in parameters such as the substrate temperature, pressure, high-frequency power, flow ratio and type of source gases (A), (B), and (C), distance between electrodes, etc. hydrogen content and / or fluorine atom content, but still were possible to control the average crystal grain size, H ₂ described above
It was inferior to the controllability by the change of the gas and / or HF gas introduction amount.

From the above, it became clear that the amounts of hydrogen radicals and fluorine radicals existing in the reaction system play an important role in forming the deposited film.

Experiment B. Examination of the relationship between the size of the average crystal grain size in the deposited film, the content of hydrogen atoms, and the content of fluorine atoms as required, and various properties of the deposited film First, light irradiation of the deposited film In order to evaluate the characteristic deterioration by the method, a part of the sample Nos. 1 to 30 prepared by the method (1) described above was cut out, and a comb-shaped electrode of Cr was deposited on each of them, and the AM-1 light was irradiated for 8 hours. (100 mW / cm ²⁾ change rate .DELTA..sigma electrical conductivity before and after the irradiation sigma was measured _{(Δσ = σ e / σ i} , σ i:: an initial value, sigma _e values after 8 hours), a sample of .DELTA..sigma ≧ 0.95 About ○, 0.95
<For samples .DELTA..sigma ≦ 0.95 △, evaluated as × for delta _sigma <0.9 samples, shown in Table 7. next,
Sample N was used to evaluate impurities contained in the deposited film.
o. A part of 1 to 30 was cut out, set in a cryostat, and irradiated with a UV lamp light (1 KW) at a temperature of 7.7 K to measure photoluminescence. As the evaluation method, sample N
with respect to the ratio _{ΔI (ΔI = I s / I} R) and the number of spectral intensity I _s from other samples with respect to the spectrum intensity I _R emerging from O.11, for samples of ΔI ≦ 0.3 ○, 0.3 <Δ
A sample with I ≦ 0.7 was evaluated as △, and a sample with ΔI> 0.7 was evaluated as ×, and the results are shown in Table 7. Next, in order to evaluate the surface smoothness of the deposited film, a part of the sample Nos. 1 to 30 was also cut out, and the surface was scanned with an FE-SEM (field emission scanning electron microscope: S-900 manufactured by Hitachi, Ltd.). Observation of the fine structure of the irregularities, the uniformity of the crystal grain size is good, the surface is rough, for samples without pinholes, ○, crystal grains are not observed, the distribution is uneven, the surface is rough, Samples having observed pinholes and the like were evaluated as x, and the results are shown in Table 7. Furthermore, these results were compared with ◎, ○, △,
The results were comprehensively evaluated in four stages of x, and are summarized in Table 7.

From the above, it was determined that the deposited film sample having a rating of ○ or more had at least various properties suitable for use in devices such as solar cells, and the physical property values of these deposited films were measured. Is 0.5 atomic% to 6 atomic%, and the content of fluorine atoms contained as required is 0 atomic% to 4 atomic%.
The atomic% and the average crystal grain size were found to be in the range of 50-800 °. Setting the physical property values within these numerical ranges,
It has been found that control is a necessary condition for forming a deposited film constituting an electronic device having desired characteristics.

Experiment C. Study on Valence Electron Control of BAs: H: F Film (1) N-type Doping Under the film forming conditions shown in Table 1 in A- (1) above, an n-type valence electron control atom was used. Se (CH ₃ ) ₂ (hereinafter abbreviated as DMSe) as a source gas containing Se atoms is packed in a bubbling apparatus, and He is bubbled as a carrier gas.
Samples Nos. 31 to 31 were prepared in exactly the same manner except that they were introduced into the activation chamber 208 together with the raw material gas (A) at a flow rate of 5 × 10 ⁻¹⁰ mol / min.
40 were fabricated.

Under the film forming conditions shown in Table 3 of A- (2), DMSe was bubbled using He gas as a carrier gas, and the film forming chamber 301 was sputtered with a sputtering gas at a flow rate of 4.5 × 10 ⁻¹¹ mol / min. Sample no.
41-50 were made.

Further, under the film forming conditions shown in Table 5 of A- (3) above, DMSe was bubbled with He gas as a carrier gas to form a film together with the source gas (A) at a flow rate of 1.5 × 10 ⁻¹⁰ mol / min. Sample N was prepared in exactly the same manner except that it was introduced into chamber 401.
o.51 to 60 were prepared.

Samples Nos. 31 to 60 produced in this manner
In addition to the same measurements and evaluations as those performed in the sections B and B, the conductivity type was evaluated by a thermoelectromotive force measurement method. As a result, Sample Nos. 4-1 to 1 obtained a comprehensive evaluation of
Sample No. corresponding to the film forming conditions of No. 0, No. 13 to 18, and No. 25 to 29
For 34 to 40, No. 43 to 48, and No. 55 to 59, almost no change was observed in any of the evaluation items, and in particular, hydrogen atom content, fluorine atom content, average crystal grain size, change in conductivity. And the photoluminescence showed good reproducibility, and the conductivity type showed n-type.

Therefore, in the present invention, the hydrogen atom content is 0.
5 atomic% to 6 atomic%, fluorine atom content is 0 atomic%
It has been found that good n-type doping can be performed by controlling the average crystal grain size within the range of 50 to 800 at%.

(2) P-type doping Under the film formation conditions shown in Table 1 in the above-mentioned A- (1), Zn (CH ₃ ) ₂ (as a source gas containing a Zn atom which is a p-type valence electron controlling atom) Hereafter abbreviated as DMZn) in a bubbling device, and bubbling with He as a carrier gas.
Samples Nos. 61 to 61 were prepared in exactly the same manner except that they were introduced into the activation chamber 208 together with the raw material gas (A) at a flow rate of 5 × 10 ⁻¹⁰ mol / min.
70 was produced.

Under the film forming conditions shown in Table 3 of A- (2) above, DMZn was bubbled using He gas as a carrier gas, and a film forming chamber was formed together with a sputtering gas at a flow rate of 7.0 × 10 ⁻¹¹ mol / min. Sample N was prepared in exactly the same way except that it was introduced into 301.
o.71 to 80 were prepared.

Further, under the film forming conditions shown in Table 5 of A- (3) above, DMZn was bubbled with He gas as a carrier gas, and the raw material gas (A) was formed at a flow rate of 1.8 × 10 ⁻¹⁰ mol / min. Samples Nos. 81 to 90 were prepared in exactly the same manner except that the sample No. was introduced into the membrane chamber 401.

Sample Nos. 61 to 90 produced in this manner
In addition to the same measurements and evaluations as those performed in the sections B and B, the conductivity type was evaluated by a thermoelectromotive force measurement method. As a result, Sample Nos. 4-1 to 1 obtained a comprehensive evaluation of
Sample No. corresponding to the film forming conditions of No. 0, No. 13 to 18, and No. 25 to 29
In 64 to 70, No. 73 to 78, and No. 85 to 89, almost no change was observed in any of the evaluation items, in particular, hydrogen atom content, fluorine atom content, average crystal grain size, change in conductivity. And the photoluminescence showed good reproducibility, and the conductivity type was p-type.

Therefore, in the present invention, the hydrogen atom content is 0.
5 atomic% to 6 atomic%, fluorine atom content is 0 atomic%
It has been found that good p-type doping can be performed by controlling the average crystal grain size within the range of 50 to 800 at%.

Summary of Experimental Results From the above results, the following was understood. That is, in the process of forming the deposited film, the presence of an appropriate amount of hydrogen radicals improves the crystal orientation of the deposited film and increases the average crystal grain size. In addition, the presence of fluorine radicals as required promotes the film formation reaction. Further, the distribution state of B atoms and As atoms in the film is also improved and uniform, and specific atoms are not clustered. The hydrogen radicals and / or fluorine radicals not only act on the film formation, but also contain an appropriate amount in the deposited film so as to terminate dangling bonds, and play an important role in improving various characteristics of the film. Will be fulfilled. For example, when irradiation with strong light is performed for a long time, a film containing no hydrogen atoms or fluorine atoms at all, or a very small amount or even an excessive amount of hydrogen atoms and fluorine atoms is unstable. Side reactions due to external factors such as bond dissociation and hydrolysis are promoted, and changes in the film structure and composition, the increase in dangling bonds due to the elimination of hydrogen atoms and / or fluorine atoms, etc. cause the initial film structure state to change. A change, that is, deterioration occurs. On the other hand, a hydrogen atom
0.5 atomic%-6 atomic%, fluorine atom 0 atomic%-4at
When the atoms are contained in the deposited film in the amount of omic%, these atoms terminate dangling bonds that may be present in the crystal grains, or dangling bonds that are said to be abundant in the crystal grain boundaries. By terminating, the so-called crystal defect state density is reduced, and at the same time, the stress generated structurally is reduced, and a film excellent in electrical, optical and mechanical properties is obtained. Therefore, since a high-quality film is formed stably without being doped, p-type and n-type doping can be easily and reliably achieved.

In the present invention, the element used for controlling the valence electrons of the BAs: H (F) film to n-type is an element belonging to Group VIA of the periodic table,
That is, O, S, Se, and Te are mentioned, and Se and Te are particularly preferably used. On the other hand, the elements used for controlling valence electrons to p-type are elements of group IIB of the periodic table, that is, Zn, Cd,
Hg is mentioned, and among them, Zn and Cd are preferably used.

Specifically, as a compound containing a group IIB element, Zn (C
H ₃ ) ₂ , Zn (C ₂ H ₅ ) ₂ , Zn (OCH ₃ ) ₂ , Zn (OC ₂ H ₅ ) ₂ , Cd (CH ₃ ) ₂ ,
Cd (C ₂ H ₅ ) ₂ , Cd (C ₃ H ₇ ) ₂ , Cd (C ₄ H ₉ ) ₂ , Hg (CH ₃ ) ₂ , Hg (C
₂ H ₅ ) ₂ , Hg (C ₆ H ₅ ) ₂ , Hg [C≡ (C ₆ H ₅ )] _{2 and the} like. Examples of the compound containing a VIA group element include NO, N ₂ O, CO 2 ₂ ,
CO, H ₂ S, SCl ₂ , S ₂ Cl ₂ , SOCl ₂ , SO ₂ Cl ₂ , SeCl ₄ , Se ₂ C
_{l 2, Se 2 Br 2,} SeOCl 2, Se (CH 3) 2, Se (C 2 H 5) 2, TeCl 2, Te
(CH ₃ ) ₂ , Te (C ₂ H ₅ ) _{2 and the} like can be mentioned.

Of course, these raw materials may be used alone or in combination of two or more. When these raw materials are in a liquid or solid state at normal temperature and normal pressure, bubbling is performed using an inert gas such as Ar or He as a carrier gas using a bubbling device, and then used in a gasified state or heated and sublimated. A sublimate is transported and used by using a furnace with an inert gas such as Ar or He as a carrier gas.

Furthermore, the elements of group IVA of the periodic table, ie, C, Si, Ge, S
n and Pb can be used as valence electron controlling atoms. That is, when these atoms replace B atoms, they become n-type, and when these atoms replace As atoms, they become p-type. Also,
When both atoms are substituted, they may be neutralized, but show either n-type or p-type conductivity depending on the difference in the substitution rate. Among them, Si, Ge, and Sn are preferably used.

Specifically, CH ₄ , C ₂ H ₆ , C ₂ H ₄ , C ₂ H ₂ , C ₃ H ₈ , C ₃ H ₆ , C
_{3 H 4, CF 4, (} CF 2) 5, (CF 2) 6, (CF 2) 4, C 2 F 6, C 3 F 8, CH
_{F 3, CH 2 F 2,} CCl 4, (CCl 2) 5, CBr 4, (CBr 2) 5, C 2 Cl 6, C 2
Br ₆ , CHCl ₃ , CH ₂ Cl ₂ , CHI ₃ , CH ₂ I ₂ , C ₂ Cl ₃ F ₃ , C ₂ H ₃ F ₃ ,
_{C 2 H 2 F 4, SiH} 4, Si 2 H 6, Si 3 H 6, (SiH 2) 4, (SiH 2) 5, (SiH
_{2) 6, SiF 4, (} SiF 2) 5, (SiF 2) 6, (SiF 2) 4, Si 2 F 6, Si
₃ F ₈ , SiHF ₃ , SiH ₂ F ₂ , SiCl ₄ , (SiCl ₂ ) ₅ , SiBr ₄ , (SiB
r ₂ ) ₅ , Si ₂ Cl ₆ , Si ₂ Br ₆ , SiHCl ₃ , SiH ₂ Cl ₂ , SiHBr ₃ , SiH
I ₃ , Si ₂ Cl ₃ F ₃ , Si ₂ H ₃ F ₃ , Si ₂ H ₂ F ₄ , Si ₂ H ₃ Cl ₃ , Si ₂ H ₂ C
_{l 4, GeH 4, Ge 2} H 6, GeF 4, (GeF 2) 5, (GeF 2) 6, (GeF 2) 4,
Ge ₂ F ₆ , Ge ₃ F ₈ , GeHF ₃ , GeH ₂ F ₂ , GeCl ₄ , (GeCl ₂ ) ₅ , GeBr
_{4, (GeBr 2) 5,} Ge 2 Cl 6, Ge 2 Br 6, GeHCl 3, GeH 2 Cl 2, GeHB
_{r 3, GeHI 3, Ge 2} Cl 3 F 3, Ge 2 H 3 F 3, Ge 2 H 3 Cl 3, Ge 2 H 2 F 4, G
e ₂ H ₂ Cl ₄ , SnH ₄ , SnCl ₄ , SnBr ₄ , Sn (CH ₃ ) ₄ , Sn (C ₂ H ₅ ) ₄ ,
Sn (C ₃ H ₇ ) ₄ , Sn (C ₄ H ₉ ) ₄ , Sn (OCH ₃ ) ₄ , Sn (OC ₂ H ₅ ) ₄ , Sn (i-
OC ₃ H ₇ ) ₄ , Sn (t-OC ₄ H ₉ ) ₄ , Pb (CH ₃ ) ₄ , Pb (C ₂ H ₅ ) ₄ , Pb (C ₄ H
₉ ) _{4 and the} like.

Of course, these raw materials can be used alone or in combination of two or more.

When the raw material is in a gaseous state under normal temperature and normal pressure, the amount introduced into the film formation space or the activation space is controlled by a mass flow controller or the like, and in a liquid state, a rare gas such as Ar or He is used. Alternatively, hydrogen gas is used as a carrier gas, and gasification is performed using a bubbler whose temperature can be controlled as necessary.If the gas is in a solid state, a rare gas such as Ar or He or a hydrogen gas is used as a carrier gas to heat the sublimation furnace. And the amount introduced is controlled mainly by the flow rate of the carrier gas and the furnace temperature.

As the raw material containing a B atom used in the methods (1) and (3) of the present invention, specifically, B ₂ H ₆ , B ₄ H ₁₀ , B ₅ H ₉ , B ₅ H ₁₁ , B ₆ H ₁₀ , B ₆ H ₁₂ , B ₆ H ₁₄
And boron halides such as BF ₃ , BCl ₃ and BBr ₃ , and B (CH ₃ ) ₃ and B (C ₂ H ₅ ) ₃ . Further, as the raw material containing an As atom, specifically,
AsH ₃ , AsF ₃ , AsF ₅ , AsCl ₃ , AsCl ₅ , AsBr _{3 and the} like can be mentioned.

Of course, these raw materials can be used alone or in combination of two or more.

When the raw material is in a gaseous state under normal temperature and normal pressure, the amount introduced into the film formation space or the activation space is controlled by a mass flow controller or the like, and in a liquid state, a rare gas such as Ar or He is used. Or, using a hydrogen gas as a carrier gas, gasification using a bubbler capable of temperature control as necessary, or in a solid state, a heating sublimation furnace using a rare gas such as Ar, He or hydrogen gas as a carrier gas. It is used for gasification, and the amount introduced is controlled mainly by the carrier gas flow rate and the furnace temperature.

BAs: H is prepared by the method of the present invention (1) to (3).
(F) In forming a film, the substrate temperature is preferably 50 ° C. to 600 ° C., more preferably 50 ° C.
C. to 450.degree. C., optimally 100.degree. The internal pressure during the film formation in the methods (1) and (3) of the present invention is preferably 1 × 10 ⁻⁴ Torr to 50 × 50.
Torr, more preferably 5 × 10 ⁻³ Torr to 10 Torr, and most preferably 1 × 10 ⁻³ Torr to 5 Torr. On the other hand, in the method (2), preferably 1 × 10 ⁻⁵ Torr
~ 1 × 10 ^-1 Torr, more preferably 1 × 10 ^-4 Torr to 1 × 10 Torr
Preferably set to ^-2 Torr.

As described above, the methods (1) to (3) of this embodiment are performed by the deposited film forming apparatus having the configuration shown in FIGS. 2 to 4, but are not limited to these configurations. Not something.

Next, the configuration of the photovoltaic element of the present invention will be described.
In configuring a photovoltaic element using a pin heterojunction, when light is incident from the p-type semiconductor layer side, when the p-type semiconductor layer is extremely thin, the amount of light absorbed by the layer is extremely small, Most of the incident light can be absorbed by the i-type semiconductor layer, and a large photocurrent is expected to be taken out.

However, reducing the thickness of the p-type semiconductor layer has limitations in physical and electrical characteristics, and several tens of thousands in film forming technology.
A thickness of about several hundreds of mm is necessary, and the amount of light absorption here cannot be ignored depending on the band gap of the p-type semiconductor layer used.

Therefore, when A-Si: H or A-Sic: H, which absorbs light on a relatively short wavelength side and generates photocarriers, is used as the i-type semiconductor layer, the light absorption in the p-type semiconductor layer is particularly large. This greatly improves the extracted photocurrent. Therefore, it is necessary that the p-type semiconductor layer be made of a semiconductor material having a wide band gap.

On the other hand, in the case of using a semiconductor material having a wide band gap for the p-type semiconductor layer and / or the n-type semiconductor layer in the pin heterojunction photovoltaic device, a high open-circuit voltage (Voc) is obtained.
Can be generated, and a high photoelectric conversion efficiency can be achieved by a synergistic effect with the above-described effect.

BAs: H having p-type or n-type conductivity according to the present invention
(F) The film is present in the film as long as it contains a specific amount of hydrogen atoms and / or fluorine atoms and has an average crystal grain size within a predetermined value range, particularly in terms of its composition and structure. Defects are greatly reduced and conventional BAs
Since the characteristics are greatly improved as compared with the film, it can be used as a material suitable for achieving the above object.

Of course, the above concept is also applied to the case where light is incident from the n-type semiconductor layer side. Furthermore, in a so-called tandem type or triple type photovoltaic element in which two or three pin heterojunction type photovoltaic elements are stacked, the p-type photovoltaic element located closest to the light incident side is the p-type according to the present invention. Alternatively, using a BAs: H (F) film having an n-type conductivity as a p-type and / or n-type semiconductor layer has a great effect.

In addition, since A-SiGe: H or μC-Si: H, which can originally take a large photocurrent, can be used as an i-type semiconductor layer because it can absorb light on a relatively long wavelength side, the BAs of the present invention having a large band gap can be used. : Electron generated in the i-type semiconductor layer by the so-called back surface field effect caused by the conduction band gap between the p-type semiconductor layer composed of the H (F) film and the i-type semiconductor layer having a narrow band gap. Reverse diffusion at the -i junction interface is prevented, and an increase in photocurrent can be expected.

As described above, the photovoltaic element of the present invention can obtain a large photocurrent, and its photoelectric conversion rate is greatly improved as compared with the conventional one.
As a result, excellent photoelectric conversion efficiency can be obtained for light sources with relatively long wavelength light components, such as fluorescent lamps, and for light sources with long wavelength light components, such as incandescent lamps. The photovoltaic element of the present invention can be suitably used as a power supply for consumer equipment.

In addition, when the tandem type or the triple type is used as described above, the deterioration of characteristics due to use is suppressed to a level that does not hinder practical use. The element can be suitably used also as a solar cell for a power supply system by solar power generation.

Hereinafter, examples of the layer configuration of the photovoltaic device of the present invention will be described.
The photovoltaic device of the present invention is not limited by this.

FIGS. 1A and 1B are diagrams schematically showing a typical example of a layer configuration when a semiconductor deposited film according to the present invention is used as a photovoltaic element of the present invention.

In the example shown in FIG. 1A, the lower electrode 10
2, n-type semiconductor layer 103, i-type semiconductor layer 104, p-type semiconductor layer 1
05 is a photovoltaic element 100 in which a transparent electrode 106 and a collecting electrode 107 are formed in this order. In this photovoltaic element, it is assumed that light is incident from the transparent electrode 106 side.

In the example shown in FIG. 1B, a transparent electrode 106, a p-type semiconductor layer 105, an i-type semiconductor layer 104, an n-type semiconductor layer 103, and a lower electrode 102 are deposited and formed in this order on a translucent support 101. This is the photovoltaic element 100 obtained. In this photovoltaic element, it is assumed that light is incident from the transparent support 101 side.

The example shown in FIG. 1 (C) is a so-called so-called pin-type photovoltaic element 111, 112, 113 using three types of semiconductor layers having different band gaps and / or layer thicknesses as i-layers. This is a triple type photovoltaic element 120. 101
Denotes a support, and the lower electrode 102, the n-type semiconductor layer 103, the i-type semiconductor layer 104, the p-type semiconductor layer 105, the n-type semiconductor layer 114, i
Semiconductor layer 115, p-type semiconductor layer 116, n-type semiconductor layer 117,
The i-type semiconductor layer 118, the p-type semiconductor layer 119, the transparent electrode 106, and the current collecting electrode 107 are laminated in this order, and it is assumed that light is incident from the transparent electrode 106 side in this photovoltaic element. .

In any of the photovoltaic elements, the n-type semiconductor layer and the p-type semiconductor layer can be used in a different order of lamination according to the purpose.

Hereinafter, the configurations of these photovoltaic elements will be described.

Support The support 101 used in the present invention may be single-crystalline or non-single-crystalline, and furthermore, they may be conductive or electrically insulating. Good. Furthermore, they may be light-transmitting or non-light-transmitting,
When light is incident from the side, it is necessary to be transparent. As specific examples of them, Fe, Ni,
Examples thereof include metals such as Cr, Al, Mo, Au, Nb, Ta, V, Ti, Pt, and Pb, and alloys thereof, for example, brass and stainless steel.

In addition to these, a film or sheet of a synthetic resin such as polyester, polyethylene, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, and polyimide, glass, and ceramics may be used.

In addition, as a single crystalline support, Si, Ge, C, NaCl, KCl, Li
F, GaSb, InAs, InSb, GaP, MgO, CaF ₂ , BaF ₂ , α-Al ₂ O ₃ etc. sliced from a single crystal and processed into a wafer, etc., and the same substance or lattice on them A material obtained by epitaxially growing a material having a constant close to that is exemplified.

The shape of the support can be plate-shaped, long belt-shaped, cylindrical, or the like having a smooth surface or an uneven surface depending on the purpose and application, and the thickness thereof is such that a desired photovoltaic element can be formed. It is determined as appropriate, but when flexibility is required as the photovoltaic element, or when light is incident from the side of the support, as much as possible within the range where the function as the support is sufficiently exhibited. Can be thin. However, the thickness is usually 10 μm or more from the viewpoints of production and handling of the support, mechanical strength and the like.

Electrode In the photovoltaic element of the present invention, an appropriate electrode is selected and used depending on the configuration of the element. Examples of these electrodes include a lower electrode, an upper electrode (transparent electrode), and a collecting electrode. (However, the upper electrode referred to here indicates an electrode provided on the light incident side, and the lower electrode indicates an electrode provided opposite to the upper electrode with a semiconductor layer interposed therebetween.) The electrodes are described in detail below.

(I) Lower Electrode As the lower electrode 102 used in the present invention, the surface to which light for generating photovoltaic light is irradiated is different depending on whether or not the material of the support 101 is translucent (for example, When the support 101 is a non-translucent material such as a metal, light for photovoltaic generation is irradiated from the transparent electrode 106 side as shown in FIG. 1 (A)). Location is different.

Specifically, in the case of a layer configuration as shown in FIGS. 1A and 1C, it is provided between the support 101 and the n-type semiconductor layer 103. However, when the support 101 is conductive, the support can also serve as the lower electrode. However, if the sheet resistance is high even if the support 101 is conductive, the electrode is used as a low-resistance electrode for extracting current or for the purpose of increasing the reflectance on the support surface and effectively using incident light. 102 may be installed.

In the case of FIG. 1 (B), a light-transmitting support 101 is used, and light enters from the support 101 side. Therefore, for the purpose of current extraction and light reflection at the electrode, A lower electrode 102 is provided facing the support 101 with the semiconductor layer interposed therebetween.

When an electrically insulating material is used as the support 101, a lower electrode 102 is provided between the support 101 and the n-type semiconductor layer 103 as an electrode for extracting current.

As electrode materials, Ag, Au, Pt, Ni, Cr, Cu, Al, Ti, Zn, Mo.
Metals such as W or alloys thereof are mentioned, and thin films of these metals are formed by vacuum evaporation, electron beam evaporation, sputtering, or the like. Further, care must be taken that the formed metal thin film does not become a resistance component with respect to the output of the photovoltaic element, and the sheet resistance is preferably 50Ω or less, more preferably 10Ω or less.

Although not shown in the figure, a diffusion preventing layer such as conductive zinc oxide may be provided between the lower electrode 102 and the n-type semiconductor layer 103. The effect of the diffusion prevention layer is not only to prevent the metal element constituting the electrode 102 from diffusing into the n-type semiconductor layer, but also to provide a small resistance value so that the lower electrode provided with the semiconductor layer interposed therebetween. To prevent short-circuiting caused by a defect such as a pinhole between the transparent electrode 106 and the transparent electrode 106;
In addition, there can be obtained an effect that multiple interference by a thin film is generated and incident light is confined in a photovoltaic element.

(Ii) Upper electrode (transparent electrode) The transparent electrode 106 used in the present invention has a light transmittance of 85% or more in order to efficiently absorb light from the sun or a white fluorescent lamp into the semiconductor layer. The sheet resistance is desirably 100Ω or less so that the output of the photovoltaic element does not become a resistance component. As a material having such properties, Sn
Metal oxides such as O ₂ , In ₂ O ₃ , ZnO, CdO, Cd ₂ SnO ₄ , ITO (In ₂ O ₃ + SnO ₂ ), and metals such as Au, Al, Cu etc. Metal thin film and the like. The transparent electrode is laminated on the p-type semiconductor layer 105 in FIG.
In FIG. 1B, since they are stacked on the substrate 101, it is necessary to select ones having good adhesion to each other. These production methods include resistance heating evaporation,
An electron beam heating vapor deposition method, a sputtering method, a spray method, or the like can be used, and is appropriately selected as desired.

(Iii) Current collecting electrode The current collecting electrode 107 used in the present invention is a transparent electrode 1
06 is provided on the transparent electrode 106 for the purpose of reducing the surface resistance value. Ag, Cr, Ni, Al, Ag, Au, Ti, P
Examples include thin films of metals such as t, Cu, Me, W, and the like, or alloys thereof. These thin films can be stacked and used. In addition, to ensure a sufficient amount of light incident on the semiconductor layer,
The shape and area are appropriately designed.

For example, it is desirable that the shape is uniformly spread over the light receiving surface of the photovoltaic element, and that the area is preferably 15% or less, more preferably 10% or less with respect to the light receiving area.

Further, as a sheet resistance value, preferably 50Ω or less,
More preferably, it is desirably 10Ω or less.

i-type semiconductor layer As the semiconductor material constituting the i-type semiconductor layer suitably used in the present invention, A-Si: H, A-Si: F, A-Si: H:
F, A-SiC: H, A-SiC: F, A-SiC: H: F, A-SiGe: H, A-SiGe:
F, A-SiGe: H: F, poly-Si: H, poly-Si: F, poly-Si: H: F.

The photovoltaic device of the present invention is a p-type and / or a p-type and / or a film composed of these i-type semiconductor layers and the aforementioned BAs: H (F) film of the present invention.
Alternatively, desired characteristics can be obtained by combination with an n-type semiconductor layer. This point will be further clarified by Experiment D described below.

Experiment D In this comparative experiment example, in addition to the constituent material of the i-type semiconductor layer described above, A-Si, A-Si
C, A-SiGe, and poly-Si are also used as the i-type semiconductor layers, and the p-type and / or n-type semiconductor layers are formed by using the BAs: H (F) film of the present invention or the BAs film by a conventional method. Heterojunction type photovoltaic devices (Sample Nos. 91 to 109) were prepared, and short-circuit current (Isc) and open-circuit voltage (Voc) under AM-1 light (100 mW / cm ² ) irradiation were measured and evaluated.

The layer configuration of the photovoltaic element is the configuration shown in FIG. 1B. The support 101 is made of quartz glass, the transparent electrode 106 is an ITO film formed by a sputtering method, and the lower electrode 102 is an electron beam heating. Light was incident from the support 101 side using an Ag thin film formed by the method.

The BAs: H (F) film as the p-type semiconductor layer of the present invention is the above-mentioned sample No. 76, and the BAs: H: F as the n-type semiconductor layer of the present invention is used.
The film was produced under the same film forming conditions as those for the above-mentioned sample No. 36.

A BAs film as a p-type semiconductor layer according to a conventional method was manufactured under the same film forming conditions as those of Sample No. 71 described above. An A-Si: H film as an n-type semiconductor layer according to a conventional method was formed by a known plasma CVD method.

As the method for forming the i-type semiconductor layer, the above-mentioned (1) to (3) described in “Study on the method for forming a BAs: H (F) film into which hydrogen atoms and fluorine atoms are introduced as necessary” are described. ), The source gas containing Si atoms, the source gas containing C atoms or the source gas containing Ge atoms is used instead of the source gas containing B atoms and the source gas containing As atoms. Alternatively, a target made of Si, SiC, SiGe or the like may be used instead of a target made of BAs or the like. Therefore, the amount of hydrogen atoms and / or fluorine atoms contained in the i-type semiconductor layer is appropriately adjusted and controlled by changing various parameters such as the H ₂ gas flow rate and the HF gas flow rate. Accordingly, as an apparatus for forming an i-type semiconductor layer, a deposited film forming apparatus having basically the same configuration as that shown in FIGS. 2 to 4 can be used. A detailed method of forming the i-type semiconductor layer will be described in Examples described later. In addition, different semiconductor layers having different material configurations or conduction types can be formed by using the same deposition film forming apparatus and changing the kind of gas to be introduced and the like. It is desirable to provide a deposited film forming apparatus.

Table 8 shows the configurations and evaluation results of various photovoltaic elements.

From these results, when a common semiconductor film is used for the i-type semiconductor layer and the n-type semiconductor layer, the p-type BAs: H (F) film of the present invention is used for the p-type semiconductor layer for both Isc and Voc. Is the case where the conventional p-type BAs film was used (sample No. 91 to
93, 97-99 and sample Nos. 104-109), all of which exhibited better characteristics. Further, when the n-type BAs: H: F film of the present invention was used for the n-type semiconductor layer, improvement in Voc and Isc was observed. On the other hand, even when the p-type BAs: H (F) film of the present invention is used, A-Si, A-SiC, A-SiGe, po containing neither hydrogen nor fluorine produced by the sputtering method as the i-type semiconductor layer.
When ly-Si was used (sample Nos. 100 to 103), characteristics that could withstand use could not be obtained.

Hereinafter, for strict distinction, amorphous silicon containing both or one of hydrogen and fluorine used in the present invention, polycrystalline silicon, an alloy of amorphous silicon and carbon, and an alloy of amorphous silicon and germanium are used. A-Si: H: F, A
−Si: H, A−Si: F, poly−Si: H: F, poly−Si: H, poly−Si: F,
A-SiC: H: F, A-Sic: H, A-Sic: F, A-SiGe: H: F, A-SiGe:
H, A-SiGe: F, and the case containing neither hydrogen nor fluorine are simply described as A-Si, poly-Si, A-SiC, A-SiGe.

From the above experimental results, p provided by the present invention
In forming a pin heterojunction photovoltaic element using a n-type and / or n-type BAs: H (F) film, a semiconductor material preferably used as an i-type semiconductor layer is A-Si: H, A-Si : F, A−
Si: H: F, A-SiC: H, A: SiC: F, A-SiC: H: F, A-SiGe: H, A-Si
Ge: F, A-SiGe: H: F, poly-Si: H, poly-Si: F, poly-Si: H:
It turned out to be F.

In the present invention, as a means for forming a good pin heterojunction, it is desirable that the formation of the n-type semiconductor layer, the formation of the i-type semiconductor layer, and the formation of the p-type semiconductor layer be performed continuously in a vacuum. Specifically, when the semiconductor layers are formed continuously in the same deposition film forming apparatus, or when the respective semiconductor layers are formed using different apparatuses, the respective deposition film forming apparatuses are connected via a gate valve or the like. For example, after forming an n-type semiconductor layer with the first deposited film forming apparatus, the substrate on which the n-type semiconductor layer is formed is transferred to a second deposited film forming apparatus under vacuum conditions, and the second deposited film is formed. An i-type semiconductor layer is formed by a film forming apparatus, and the substrate formed up to the i-type semiconductor layer is transported to a third deposited film forming apparatus under vacuum conditions. What is necessary is just to form a p-type semiconductor layer.

〔Example〕

Hereinafter, the photovoltaic device of the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1 The pin heterojunction type photovoltaic element shown in FIG. 1A was formed by using the deposition film forming apparatus having the structure shown in FIG. Produced by the procedure.

After placing a stainless steel substrate 101 having a size of 50 mm × 50 mm in a sputtering apparatus (not shown) and evacuating it to 10 ⁻⁵ Torr or less, the substrate 101
An Ag thin film of about 1000 ° serving as the lower electrode 102 was deposited thereon.
The substrate 101 is taken out, and the lower electrode is placed on a substrate holding cassette 202 on a substrate transfer jig 206 in the load lock chamber 212.
The surface on which 102 was deposited was fixed facing downward in the figure, and the inside of the load lock chamber 212 was evacuated to a pressure of 10 ^-5 Torr or less by an exhaust pump (not shown). During this time, the deposition chamber 201 is
Due to 21, the gas is exhausted to a pressure of 10 ^-5 Torr or less. When the pressures in both chambers became substantially equal, the gate valve 207 was opened, the substrate holding cassette 202 was moved into the film forming chamber 201 using the substrate transfer jig 206, and the gate valve 207 was closed again.

Next, heating was performed by the heater 205 so that the surface temperature of the substrate 203 became 220 ° C. When the substrate temperature stabilizes,
25 sccm of Si ₂ F ₆ gas and PH ₃ (Si
While mixing the 4000ppm dilution) gas 10sccm at F _4, it was introduced into the activation chamber 208 which is heated to keep 7000 ° C. from the gas supply pipe 214 in an electric furnace 211. At the same time, each of 100sccm and 50s He gas and H ₂ gas stored in the gas cylinder (not shown)
The mixture was mixed at a flow rate of ccm and introduced into the activation chamber 209 from the gas supply pipe 25. Next, the opening degree of the exhaust valve 220 is adjusted,
While maintaining the internal pressure of the film forming chamber 201 at 0.3 Torr, 300 W microwave power was supplied from the 2.45 GHz microwave generator 212 into the activation chamber 209. The precursor, hydrogen radicals, and the like introduced into the film forming chamber 201 from the transport pipes 217 and 218 immediately reacted to deposit and form an A-Si: H: F film 103 as an n-type semiconductor layer. After depositing and forming a 400 ° n-type A-Si: H: F film, the introduction of source gas and the supply of microwave power are stopped to exhaust pump.
The inside of the film forming chamber 201 was evacuated to 10 ⁻⁵ Torr or less by 221.
Next, the substrate 203 formed up to the n-type semiconductor layer 103 was moved using the substrate transfer jig 206 to the film formation chamber 222 evacuated to 10 ⁻⁵ Torr with the same configuration as the film formation chamber 201. . Hereinafter, since the configuration inside the film forming chamber 222 is the same as that of the film forming chamber 201, it will be described using the same drawing numbers as those shown in FIG.

Next, the introduction of PH ₃ gas as a source gas for doping was stopped, Si ₂ F ₆ gas was introduced at 30 sccm, and microwave power was increased to 400
An A-Si: H: F film 104 was formed as an i-type semiconductor layer at 3500 ° under the same conditions as above except that W was used.

After the film formation, the introduction of the gas and the supply of the microwave power were stopped, and the inside of the film formation chamber 222 was evacuated to 10 ^-5 Torr.

Next, the substrate 203 formed up to the i-type semiconductor layer 104 was transferred to a film formation chamber (not shown) having the same configuration as the film formation chamber 201 by the same operation as described above. Therefore, BF ₃ gas 6sccm and He gas 5scc
m is used as a carrier gas, and a gas obtained by bubbling Zn (CH ₃ ) ₂ filled in a bubbling device (not shown) at a flow rate of 3.0 × 10 ⁻⁸ mol / min is supplied to a gas supply pipe 214.
And introduced into the activation chamber 208. The microwave power of 60 W was immediately supplied from the microwave generator 211 into the activation chamber 208. At the same time, supply 6 sccm of AsH ₃ gas to gas supply pipe 2
Introduced into the activation chamber 210 which is heated and held at 500 ° C. in the electric furnace 213 via 16, and a mixed gas of 8 sccm of H ₂ gas and 40 sccm of He gas is introduced into the activation chamber 209 via the gas supply pipe 215. Then, microwave power of 300 W was supplied from the microwave generator 212 into the activation chamber 209. At this time, the pressure in the film forming chamber 201 was controlled at 60 mTorr. Via the transport pipes 217, 218, 219, the precursors generated in the activation chambers 208, 209, 210, hydrogen radicals, etc. are introduced into the film formation chamber 201 and immediately cause a chemical reaction,
210 ° C provided at a position 8 cm from the gas outlet of the transport pipe 218
BAs as a p-type semiconductor layer on the substrate 203 heated and held in:
An H: F film was formed.

After laminating a 200 ° p-type BAs: H: F film on the i-type semiconductor layer 104, a load lock chamber (not shown) for taking out the substrate holding cassette 202 through the gate valve 207 with the substrate transfer jig 206. After cooling, the substrate 203 on which the n-type, i-type and p-type semiconductor layers were deposited was taken out. The substrate 203 is made of In and Sn
Is placed in a vacuum deposition apparatus equipped with a deposition boat filled with metal particles of a weight ratio of 1: 1 and evacuated to 10 ^-5 Torr or less, and then oxygen of about 1 × 10 ^-3 Torr is applied by a resistance heating method. In the atmosphere, an ITO thin film as the transparent electrode 106 was deposited by about 700 °. The substrate heating temperature at this time was 170 ° C. After cooling, the substrate 203 is taken out, a permalloy mask for forming a current collecting electrode pattern is brought into close contact with the upper surface of the transparent electrode 106, placed in a vacuum evaporation apparatus, and evacuated to 1 × 10 ⁻⁵ Torr or less, and then subjected to a resistance heating method. Then, Ag was vapor-deposited to a thickness of about 0.8 μm to form a comb-shaped current collecting electrode 107. The photovoltaic element thus formed was referred to as Element No. 1.

 The characteristics of the device No. 1 were evaluated as follows.

AM-1 light (100 mW / cm ² ) from the transparent electrode 106 side of device No. 1
Open voltage Voc and short-circuit current Isc when irradiating
The relative value of the output when the AM-1 light was irradiated through a 400 nm interference filter (relative value to the measured value of the device manufactured in Comparative Example 1 described below under the same conditions) was measured.
Table 9 shows the measurement results.

Separately, using a quartz glass substrate, BAs as a p-type semiconductor layer using the same method and procedure as described above:
The H: F film was formed alone. With respect to the obtained deposited film, the contents of hydrogen atoms and fluorine atoms in the film and the average crystal grain size were measured in the same manner as in the above-mentioned [Experiment]. The measurement results are shown in Table 9.

Example 2 In this example, a BAs: H: F film as a p-type semiconductor layer was formed using the deposited film forming apparatus shown in FIG. 3 in the pin heterojunction type photovoltaic element in Example 1.

Therefore, in the pin heterojunction type photovoltaic element shown in FIG. 1A, the operation is the same as that of the first embodiment up to the formation of the substrate 101, the lower electrode 102, the n-type semiconductor layer 103, and the i-type semiconductor layer 104. I went.

The substrate 303 fixed to the substrate holding cassette 302 and deposited up to the i-type semiconductor layer is deposited by the substrate transport jig 306 into the film forming chamber 30.
1 and heat the substrate 303 while keeping it at 10 ^-5 Torr or less.
Heat at 305 to 220 ° C, and when the substrate temperature stabilizes,
Sputtering was started under the conditions shown in the table and the i-type semiconductor layer was
A BAs: H: F film 105 as a 200 ° p-type semiconductor layer was deposited on 104.

After the film formation, the substrate 303 is moved from the film formation chamber 301 to a take-out load lock chamber (not shown), cooled, taken out, and subjected to the same operation and method as in the first embodiment.
The ITO film as 106 is 700 mm, and a comb-shaped Ag thin film as the current collecting electrode 107 is deposited thereon at 0.8 μm to form an element No. 2,
The same solar cell characteristics as in Example 1 were evaluated. The evaluation results are shown in Table 9.

Separately, using a quartz glass substrate, BAs: H: F as a p-type semiconductor layer was formed under the same film forming conditions as shown in Table 10.
The film was deposited. For the obtained deposited film, the content of hydrogen atoms and fluorine atoms in the film and the average crystal grain size were measured in the same manner as in Example 1. The measurement results are shown in Table 9.

Example 3 In this example, a BAs: H: P film as a p-type semiconductor layer was formed using the deposited film forming apparatus shown in FIG. 4 in the pin heterojunction photovoltaic device in Example 1.

Therefore, in the pin heterojunction type photovoltaic element shown in FIG. 1A, the operation is the same as that of the first embodiment up to the formation of the substrate 101, the lower electrode 102, the n-type semiconductor layer 103, and the i-type semiconductor layer 104. I went.

The substrate 403 fixed to the substrate holding cassette 402 and deposited up to the i-type semiconductor layer 104 is deposited by the substrate transport jig 406 into the film forming chamber 40.
1 and heat the substrate 403 while keeping it at 10 ^-5 Torr or less.
Heat at 405 to 230 ° C, and when the substrate temperature stabilizes,
Under the conditions shown in the table, the source gas (A), the source gas (B), and the source gas (C) were introduced into the film formation chamber 401 from the gas introduction pipes 408 and 409, respectively, and the opening of the exhaust valve 414 was adjusted. Deposition chamber
The internal pressure of 401 was maintained at 0.8 Torr while monitoring with a pressure gauge 417. The high-frequency power supply 410 is connected to the cathode electrode 412 via a matching circuit 411, and the high-frequency power supply 410
Immediately, a 3.56 MHz high-frequency power of 70 W was applied to start film formation. Thus, A-Si: H: F as an i-type semiconductor layer
On the film 104, a BAs: H: F film 105 as a p-type semiconductor layer was deposited at 200 °.

After completion of the film formation, the substrate 403 is moved from the film formation chamber 401 to a load lock chamber (not shown) for removal, cooled, taken out, and subjected to the same operation and method as in the first embodiment.
An ITO film as No. 6 was 700 °, and a comb-shaped Ag thin film as the current collecting electrode 107 was deposited thereon at 0.8 μm to obtain a device No. 3, and the same solar cell characteristics as in Example 1 were evaluated. The evaluation results are shown in Table 9.

Separately, using a quartz glass substrate, BAs: H: F as a p-type semiconductor layer was formed under the same film forming conditions as shown in Table 11.
The film was deposited. For the obtained deposited film, the content of hydrogen atoms and fluorine atoms in the film and the average crystal grain size were measured in the same manner as in Example 1. The measurement results are shown in Table 9.

Example 4 In this example, an A-SiC: H: F film was used in place of the A-Si: H: F film as the i-type semiconductor layer in the pin heterojunction type photovoltaic device in Example 1. Therefore, in the pin heterojunction type photovoltaic element shown in FIG. 1A, the operations up to the formation of the substrate 101, the lower electrode 102, and the n-type semiconductor layer 103 were performed in exactly the same manner as in Example 1.

Next, the n-type semiconductor layer is transferred to a film forming chamber (the structure is the same as that of the film forming chamber 201, and will be described with a common drawing number) which is completely evacuated to 10 ^-5 Torr with the same structure as the film forming chamber 201. The substrate 203 formed up to this point is opened by opening the gate valve 207, transferred using the substrate transfer jig 206, and closed by the gate valve 207, and the film forming chamber is opened.
Heating substrate 203 while maintaining the pressure in 201 at 10 ^-5 Torr
Heat to 220 ° C with 205.
Under the conditions shown in the table, the source gas (A), the source gas (B), and the source gas (C) were respectively supplied to gas supply pipes 214, 215, and 21.
From 6, the excited species were introduced into the activation chambers 208, 209 and 210 to be excited species, and the excited species were introduced into the film formation chamber 201 via the transport pipes 217, 218 and 219 to start film formation. Table 12 shows the excitation energy generators and excitation conditions used.

Thus, the A-Si: H: F film as the n-type semiconductor layer
An A-SiC: H: F film 104 as an i-type semiconductor layer 104
Å Deposited.

Next, BAs: H: F as the p-type semiconductor layer 105 was set at 200 °, the ITO film as the transparent electrode 106 was set at 700 °, and the comb as the current collecting electrode 107 was formed by the same operation and method as in Example 1. An Ag thin film having a shape of 0.8 μm was deposited to obtain a device No. 4, and the same solar cell characteristics as in Example 1 were evaluated. The evaluation results are shown in Table 9.

Separately, using a quartz glass substrate, BAs as a p-type semiconductor layer were formed under the same film forming conditions as in Example 1.
An H: F film was deposited. For the obtained deposited film, the content of hydrogen atoms and fluorine atoms in the film and the average crystal grain size were measured in the same manner as in Example 1. The measurement results are shown in Table 9.

Example 5 In this example, an A-SiGe: H: F film was used in place of the A-Si: H: F film as the i-type semiconductor layer in the pin heterojunction photovoltaic device in Example 1. Therefore, in the pin heterojunction type photovoltaic element shown in FIG. 1A, the operations up to the formation of the substrate 101, the lower electrode 102, and the n-type semiconductor layer 103 were performed in exactly the same manner as in Example 1.

Next, the n-type semiconductor layer is transferred to a film forming chamber (the structure is the same as that of the film forming chamber 201, and will be described with a common drawing number) which is completely evacuated to 10 ^-5 Torr with the same structure as the film forming chamber 201. The substrate 203 formed up to this point is opened by opening the gate valve 207, transferred using the substrate transfer jig 206, and closed by the gate valve 207, and the film forming chamber is opened.
Heating substrate 203 while maintaining the pressure in 201 at 10 ^-5 Torr
Heat to 220 ° C with 205.
Under the conditions shown in the table, the source gas (A), the source gas (B), and the source gas (C) were respectively supplied to gas supply pipes 214, 215, and 21.
From 6, the excited species were introduced into the activation chambers 208, 209 and 210 to be excited species, and the excited species were introduced into the film formation chamber 201 via the transport pipes 217, 218 and 219 to start film formation. Table 13 shows the excitation energy generators and excitation conditions used.

Thus, the A-Si: H: F film as the n-type semiconductor layer
An A-SiGe: H: F film 104 as an i-type semiconductor layer is
Å Deposited.

Next, by the same operation and method as those performed in Example 1, the BAs: H: F film as the p-type semiconductor layer 105 was 200 °, the ITO film as the transparent electrode 106 was 700 °, and the comb as the current collecting electrode 107 was formed. An element No. 5 was formed by depositing a tooth-shaped Ag thin film of 0.8 μm, and the same solar cell characteristics as in Example 1 were evaluated. The evaluation results are shown in Table 9.

Separately, using a quartz glass substrate, BAs as a p-type semiconductor layer were formed under the same film forming conditions as in Example 1.
An H: F film was deposited. For the obtained deposited film, the content of hydrogen atoms and fluorine atoms in the film and the average crystal grain size were measured in the same manner as in Example 1. The measurement results are shown in Table 9.

Example 6 In this example, a poly-Si: H: F film was used in place of the A-Si: H: F film as the i-type semiconductor layer in the pin heterojunction type photovoltaic device in Example 1. Therefore, in the pin heterojunction type photovoltaic element shown in FIG. 1A, the operations up to the formation of the substrate 101, the lower electrode 102, and the n-type semiconductor layer 103 were performed in exactly the same manner as in Example 1.

Next, the n-type semiconductor layer is transferred to a film forming chamber (the structure is the same as that of the film forming chamber 201, and will be described with a common drawing number) which is completely evacuated to 10 ^-5 Torr with the same structure as the film forming chamber 201. The substrate 203 formed up to this point is opened by opening the gate valve 207, transferred using the substrate transfer jig 206, and closed by the gate valve 207, and the film forming chamber is opened.
Heating substrate 203 while maintaining the pressure in 201 at 10 ^-5 Torr
Heat to 220 ° C with 205, and when the substrate temperature stabilizes,
Under the conditions shown in the table, the source gas (A) and the source gas (B) were supplied from the gas supply pipes 214 and 215 to the activation chambers 208 and 209, respectively.
Then, the excited species were introduced into the inside of the film formation chamber 201 via the transport pipes 217 and 218 to start film formation. Table 14 shows the used excitation energy generators and excitation conditions.

Thus, the A-Si: H: F film as the n-type semiconductor layer
A poly-Si: H: F film 104 as an i-type semiconductor layer 104
Å Deposited.

Next, by the same operation and method as those performed in Example 1, the BAs: H: F film as the p-type semiconductor layer 105 was 200 °, the ITO film as the transparent electrode 106 was 700 °, and the comb as the current collecting electrode 107 was formed. A tooth-shaped Ag thin film was deposited at 0.8 μm to obtain an element No. 6, and the same solar cell characteristics as in Example 1 were evaluated. The evaluation results are shown in Table 9.

Separately, using a quartz glass substrate, BAs as a p-type semiconductor layer were formed under the same film forming conditions as in Example 1.
An H: F film was deposited. For the obtained deposited film, the content of hydrogen atoms and fluorine atoms in the film and the average crystal grain size were measured in the same manner as in Example 1. The measurement results are shown in Table 9.

Example 7 In this example, a pin heterojunction type photovoltaic element having the structure shown in FIG. 1B was manufactured using a glass substrate instead of a stainless steel substrate, and the same characteristic evaluation as in Example 1 was performed. Was done. The manufacturing method is described below.

Transparent electrode 106 on Corning # 7059 glass substrate 101
An ITO film was formed at 500 ° by the same resistance heating method as in Example 1, and a BAs: H: F film as a p-type semiconductor layer was formed on the ITO film by 200 ° by the same operation and method as in Example 1. Deposited.
Subsequently, an A-Si: H: F film as an i-type semiconductor layer was deposited at 3500 ° by the same operation and method as in Example 1. Further, the same operation and method as in Example 1 were repeated to obtain AS as an n-type semiconductor layer.
An i: H: F film was deposited for 400 mm.

Next, an Ag thin film as the lower electrode 102 was deposited to a thickness of 0.5 μm by the same operation and method as in Example 1, and the device was fabricated.
As No. 7, the same solar cell characteristics as in Example 1 were evaluated. The evaluation results are shown in Table 9.

Separately, using a quartz glass substrate, BAs as a p-type semiconductor layer were formed under the same film forming conditions as in Example 1.
An H: F film was deposited. For the obtained deposited film, the content of hydrogen atoms and fluorine atoms in the film and the average crystal grain size were measured in the same manner as in Example 1. The measurement results are shown in Table 9.

Embodiment 8 This embodiment uses the BAs: H: F film of the present invention instead of the A-Si: H: F film also for the n-type semiconductor layer in the pin heterojunction type photovoltaic device of Example 1. . Therefore, in the pin heterojunction type photovoltaic element shown in FIG. 1A, the operation up to the formation of the substrate 101 and the lower electrode 102 was performed in exactly the same manner as in Example 1.

Next, the film formation chamber is completely evacuated to 10 ⁻⁵ Torr with the same structure as the film formation chamber 201 (the structure is the same as that of the film formation chamber 201 and will be described with a common drawing number). The formed substrate 203 is opened by opening the gate valve 207, transferred using the substrate transfer jig 206, and closed by the gate valve 207, and the film forming chamber is opened.
Heating substrate 203 while maintaining the pressure in 201 at 10 ^-5 Torr
Heat to 220 ° C with 205.
Under the conditions shown in the table, the source gas (A), the source gas (B), and the source gas (C) were respectively supplied to gas supply pipes 214, 215, and 21.
From 6, the excited species were introduced into the activation chambers 208, 209 and 210 to be excited species, and the excited species were introduced into the film formation chamber 201 via the transport pipes 217, 218 and 219 to start film formation. Table 15 shows the used excitation energy generators and excitation conditions.

In this manner, a BAs: H: F film as the n-type semiconductor layer 103 was deposited on the lower electrode 102 at a thickness of 400 Å.

Then, the A-Si: H: F film as the i-type semiconductor layer 104 was formed at 3500 ° by the same operation and method as in Example 1.
The BAs: H: F film as the p-type semiconductor layer 105 is 200 mm thick, and the transparent electrode 1
Example 1 was prepared by depositing an ITO film 700 of 700 mm and a comb-shaped Ag thin film of 0.8 μm as a current collecting electrode 107 to obtain an element No. 8.
The same solar cell characteristics were evaluated. The evaluation results are shown in Table 9.

Separately, using a quartz glass substrate, BAs as a p-type semiconductor layer were formed under the same film forming conditions as in Example 1.
An H: F film and a BAs: H: F film as an n-type semiconductor layer were deposited under the film forming conditions shown in Table 15. For the obtained deposited film, the content of hydrogen atoms and fluorine atoms in the film and the average crystal grain size were measured in the same manner as in Example 1. The measurement results are shown in Table 9.

Embodiment 9 This embodiment is directed to a pin heterojunction photovoltaic element according to Embodiment 1 in which BAs formed by a conventional sputtering method instead of the A-Si: H: F film as the n-type semiconductor layer. A membrane is used. Therefore, in the pin heterojunction type photovoltaic element shown in FIG. 1A, the formation of the substrate 101, the lower electrode 102, the i-type semiconductor layer 104, the p-type semiconductor layer 105, and the transparent electrode 106
The formation of the current collecting electrode 107 was performed in exactly the same manner as in Example 1.

The BAs film as the n-type semiconductor layer 103 was formed using the deposition film forming apparatus shown in FIG. 3 under the conditions shown in Table 16.

The solar cell thus formed was designated as element No. 9,
The solar cell characteristics and the like were evaluated. Table 17 shows the evaluation results.

Embodiment 10 In this embodiment, a pin heterojunction type photovoltaic device according to Embodiment 1 is replaced by an A-SiGe film formed by a plasma CVD method instead of an A-Si: H: F film as an n-type semiconductor layer. : H: F film is used. Accordingly, in the pin heterojunction photovoltaic element shown in FIG. 1A, the formation of the substrate 101 and the lower electrode 102 and the formation of the i-type semiconductor layer 104, the p-type semiconductor layer 105, the transparent electrode 106, and the current collecting electrode 107 Was performed in exactly the same manner as in Example 1.

The A-SiGe: H: F film as the n-type semiconductor layer 103 was formed using the deposition film forming apparatus shown in FIG. 4 under the conditions shown in Table 18.

The solar cell thus formed was designated as element No. 10, and the solar cell characteristics and the like were evaluated. The evaluation results
The results are shown in Table 17.

Embodiment 11 In this embodiment, an A-SiC film formed by a plasma CVD method in place of the A-Si: H: F film as the n-type semiconductor layer in the pin heterojunction photovoltaic device in the first embodiment is described. : H: F film is used. Accordingly, in the pin heterojunction photovoltaic element shown in FIG. 1A, the formation of the substrate 101 and the lower electrode 102 and the formation of the i-type semiconductor layer 104, the p-type semiconductor layer 105, the transparent electrode 106, and the current collecting electrode 107 Was performed in exactly the same manner as in Example 1.

The formation of the A-SiC: H: F film as the n-type semiconductor layer 103 is the fourth step.
The deposition was performed under the conditions shown in Table 19 using the deposited film forming apparatus shown in the figure.

The solar cell thus formed was designated as element No. 11, and the solar cell characteristics and the like were evaluated. The evaluation results
The results are shown in Table 17.

Example 12 In this example, a GaAs film formed by a sputtering method was used instead of the A-Si: H: F film as the n-type semiconductor layer in the pin heterojunction photovoltaic device in Example 1. ing. Accordingly, in the pin heterojunction photovoltaic element shown in FIG. 1A, the formation of the substrate 101 and the lower electrode 102 and the formation of the i-type semiconductor layer 104, the p-type semiconductor layer 105, the transparent electrode 106, and the current collecting electrode 107 Was performed in exactly the same manner as in Example 1.

The GaAs film as the n-type semiconductor layer 103 was formed using the deposition film forming apparatus shown in FIG. 3 under the conditions shown in Table 20.

The solar cell thus formed was designated as element No. 12, and the solar cell characteristics and the like were evaluated. The evaluation results
The results are shown in Table 17.

Embodiment 13 This embodiment uses an A-Si: H film instead of the A-Si: H: F film as the i-type semiconductor layer in the pin heterojunction photovoltaic device of the eighth embodiment.

Therefore, except that the i-type semiconductor layer 104 was formed, a solar cell was formed by the same operation and method as in Example 8.

The formation of the A-Si: H film as the i-type semiconductor layer 104 was performed using the deposition film forming apparatus shown in FIG. 4 under the conditions shown in Table 21.

The solar cell thus formed was designated as element No. 13, and the solar cell characteristics and the like were evaluated. The evaluation results
The results are shown in Table 17.

Embodiment 14 In the present embodiment, an A-SiGe: H film is used in place of the A-Si: H: F film as the i-type semiconductor layer in the pin heterojunction photovoltaic element in the eighth embodiment.

Therefore, except that the i-type semiconductor layer 104 was formed, a solar cell was formed by the same operation and method as in Example 8.

The formation of the A-SiGe: H film as the i-type semiconductor layer 104 was performed using the deposition film forming apparatus shown in FIG. 4 under the conditions shown in Table 22.

The solar cell thus formed was designated as element No. 14, and the solar cell characteristics and the like were evaluated. The evaluation results
The results are shown in Table 17.

Embodiment 15 This embodiment uses an A-SiC: H film instead of the A-Si: H: F film as the i-type semiconductor layer in the pin heterojunction photovoltaic device of the eighth embodiment.

Therefore, except that the i-type semiconductor layer 104 was formed, a solar cell was formed by the same operation and method as in Example 8.

The formation of the A-SiC: H film as the i-type semiconductor device 104 is the fourth.
The deposition was performed under the conditions shown in Table 23 using the deposited film forming apparatus shown in the figure.

The solar cell thus formed was designated as element No. 15, and the solar cell characteristics and the like were evaluated. The evaluation results
The results are shown in Table 17.

Embodiment 16 In this embodiment, an A-Si: F film is used in place of the A-Si: H: F film as the i-type semiconductor layer in the pin heterojunction photovoltaic device of the eighth embodiment.

Therefore, except that the i-type semiconductor layer 104 was formed, a solar cell was formed by the same operation and method as in Example 8.

The i-type A-Si: F film was formed using the deposition film forming apparatus shown in FIG. 3 under the conditions shown in Table 24.

The solar cell thus formed was designated as element No. 16, and the solar cell characteristics and the like were evaluated. The evaluation results
The results are shown in Table 17.

Embodiment 17 In this embodiment, an A-SiGeC: H film is used in place of the A-Si: H: F film as the i-type semiconductor layer in the pin heterojunction photovoltaic device of the eighth embodiment.

Therefore, except that the i-type semiconductor layer 104 was formed, a solar cell was formed by the same operation and method as in Example 8.

The i-type A-SiGeC: H film was formed using the deposition film forming apparatus shown in FIG. 4 under the conditions shown in Table 25.

The solar cell thus formed was designated as element No. 17, and the solar cell characteristics and the like were evaluated. The evaluation results
The results are shown in Table 17.

Embodiment 18 In this embodiment, a poly-Si: H film is used instead of the A-Si: H: F film as the i-type semiconductor layer in the pin heterojunction photovoltaic device of the eighth embodiment.

Therefore, except that the i-type semiconductor layer 104 was formed, a solar cell was formed by the same operation and method as in Example 8.

The i-type poly-Si: H film was formed using the deposition film forming apparatus shown in FIG. 3 under the conditions shown in Table 26.

The solar cell thus formed was designated as element No. 18, and the solar cell characteristics and the like were evaluated. The evaluation results
The results are shown in Table 17.

Example 19 This example is directed to a pin heterojunction photovoltaic device shown in FIG. 1B, in which 103 is an n-type semiconductor layer, 105 is a p-type semiconductor layer, and p-type semiconductor layer 105 and i-type semiconductor layer. Layer 104 A
This is an element in which an n-type semiconductor layer 103 is made of a Si: H: F film and the BAs: H: F film of the present invention, and light is incident from the glass substrate 101 side.

The i-type semiconductor layer 104 is formed by the same operation and method as those formed in the eighth embodiment, and the p-type semiconductor layer 105 is formed by the n-type semiconductor layer 105 in the first embodiment. A
-Si: H: BF ₃ in place of PH ₃ at F film formation conditions (H ₂ at 4000
ppm dilution) was introduced in exactly the same manner and method except that 35 sccm was introduced.

Further, the formation of the substrate 101, the lower electrode 102, and the transparent electrode 106 was performed by exactly the same operation and method as in Example 7.

The solar cell thus formed was designated as element No. 19, and the solar cell characteristics and the like were evaluated. The evaluation results
It is shown in Table 27.

Embodiment 20 This embodiment is directed to a pin heterojunction type photovoltaic device shown in FIG. 1B in which 103 is an n-type semiconductor layer, 105 is a p-type semiconductor layer, and p-type semiconductor layer 105 is A-SiC. : H: F film, i-type semiconductor layer 104 is composed of A-Si: H: F film, and n-type semiconductor layer 103 is composed of BAs: H: F film of the present invention, and light is incident from the glass substrate 101 side. This is an element that is adapted to be used.

The i-type semiconductor layer 104 is formed in the same operation and method as those formed in the eighth embodiment, and the p-type semiconductor layer 105 is formed in the n-type semiconductor layer 105 in the eleventh embodiment. A
-SiC: H: BF at F film formation conditions in place of PH _{3 3} (H ₂ at 400
Except for introducing 30 sccm (0 ppm dilution), it was formed in exactly the same operation and method.

Further, the formation of the substrate 101, the lower electrode 102, and the transparent electrode 106 was performed by exactly the same operation and method as in Example 7.

The solar cell thus formed was designated as element No. 20, and the solar cell characteristics and the like were evaluated. The evaluation results
It is shown in Table 27.

Example 21 In this example, in the pin heterojunction photovoltaic element shown in FIG. 1B, 103 is an n-type semiconductor layer, 105 is a p-type semiconductor layer, and p-type semiconductor layer 105 is a ZnTe film. The i-type semiconductor layer 104 is an A-Si: H: F film, and the n-type semiconductor layer 103 is a BA of the present invention.
This is an element formed of an s: H: F film and receiving light from the glass substrate 101 side.

The i-type semiconductor layer 104 was formed in Example 1 and the n-type semiconductor layer 103 was formed by exactly the same operation and method as those formed in Example 8.

The p-type ZnTe film was formed using the deposition film forming apparatus shown in FIG. 3 under the conditions shown in Table 28.

The formation of the substrate 101, the lower electrode 102, and the transparent electrode 106 was performed by exactly the same operation and method as in Example 7.

The solar cell thus formed was designated as element No. 21, and the solar cell characteristics and the like were evaluated. The evaluation results
It is shown in Table 27.

Embodiment 22 In this embodiment, in the pin heterojunction photovoltaic device shown in FIG. 1B, 103 is an n-type semiconductor layer, 105 is a p-type semiconductor layer, and p-type semiconductor layer 105 is a conventional method. With BAs membrane,
This is an element in which the i-type semiconductor layer 104 is composed of an A-Si: H: F film, the n-type semiconductor layer 103 is composed of the GaP: H: F film of the present invention, and light is incident from the glass substrate 101 side. .

The i-type semiconductor layer 104 was formed in Example 1 and the n-type semiconductor layer 103 was formed by exactly the same operation and method as those formed in Example 8.

The p-type BAs film was formed using the deposition film forming apparatus shown in FIG. 3 under the conditions shown in Table 29.

The formation of the substrate 101, the lower electrode 102, and the transparent electrode 106 was performed by exactly the same operation and method as in Example 7.

The solar cell thus formed was designated as element No. 22, and the solar cell characteristics and the like were evaluated. The evaluation results
It is shown in Table 27.

Embodiment 23 In this embodiment, a so-called triple formed by stacking three pin heterojunction type photovoltaic elements using three types of semiconductor films having different band gaps as i-layers as shown in FIG. A photovoltaic device 120 was produced.

From the substrate 101 to the p-type semiconductor layer 105, a first-layer photovoltaic element 111 in which the i-type semiconductor layer is composed of an A-SiGe: H: F film is manufactured in exactly the same operation and method as in the fifth embodiment. did.

Next, an n-type semiconductor layer 114, an i-type semiconductor layer 115, and a p-type semiconductor layer 116 are deposited by exactly the same operation and method as in Example 1, and the i-type semiconductor layer is formed of an A-Si: H: F film. A second layer photovoltaic element 112 was produced. However, at this time, the thickness of the i-type semiconductor layer was 3000 °. Subsequently, the n-type semiconductor layer 117, the i-type semiconductor layer 118, and the p-type
A type semiconductor layer 119 was deposited, and a third layer photovoltaic element 113 in which the i-type semiconductor layer was formed of an A-SiC: H: F film was manufactured. However, at this time, the thickness of the i-type semiconductor layer was 2500 °. Furthermore,
In the same operation and method as in Example 1, an ITO film as the transparent electrode 106 was deposited at 700 Å and a comb-shaped Ag thin film as the current collecting electrode 107 was deposited at 0.8 μm to obtain an element No. 23, and evaluation of solar cell characteristics and the like Was done. Table 30 shows the measurement results.

Comparative Example 1 In this comparative example, an A-Si: H: F film having a thickness of 200 ° instead of the BAs: H: F film as the p-type semiconductor layer 105 in the pin heterojunction photovoltaic device of Example 1 A photovoltaic element for comparison was produced in exactly the same operation and method except that was used.
Here, the p-type semiconductor layer 105 was formed using a deposition film forming apparatus having the same configuration as that shown in FIG.
i ₂ F ₆ gas 30sccm and BF ₃ (4000 ppm diluted with SiF ₄₎ gas 8scc
m while mixing with the electric furnace 211 from the gas supply pipe 214.
And introduced into the activation chamber 208 which is heated and maintained at 700 ° C. At the same time, He gas and H ₂ gas stored in a cylinder (not shown) were mixed at a flow rate of 120 sccm and 60 sccm, respectively, and introduced into the activation chamber 209 from the gas supply pipe 215. Immediately, microwave power of 320 W is supplied from the microwave generator 212 to the activation room 2.
09 and the film formation was started. At this time, the internal pressure of the film forming chamber 201 was set to 0.35 Torr. In this way, the comparative element N
o.24 was prepared and the solar cell characteristics and the like were evaluated. Table 31 shows the measurement results.

Comparative Example 2 The same operation and method as in Example 1 were performed except that H ₂ gas was not introduced when the p-type semiconductor layer 105 was deposited using the pin heterojunction photovoltaic device. element
No. 25 was produced. In the first embodiment, the p-type semiconductor layer 1
Element No. 26 for comparison was produced in exactly the same operation and method except that the flow rate of H ₂ gas was set to 0.5 sccm when depositing 05. Evaluation of the solar cell characteristics of these devices was performed in the same manner as in Example 1. Table 31 shows the measurement results.

Comparative Example In Example 1, when depositing the p-type semiconductor layer, BF ₃
Gas 5 sccm, Zn (CH ₃ ) ₂ flow rate 5.0 × 10 ⁻⁸ mol / min, AsH
An element No. 27 for comparison was prepared by the same operation and method except that the flow rate of the _three gases was changed to 15 sccm, and the solar cell characteristics and the like were evaluated. Table 31 shows the measurement results.

Comparative Example 4 The device shown in FIG. 3 was used instead of the A-Si: H: F film as the i-type semiconductor layer 104 in the pin heterojunction photovoltaic device in Example 1, and the results are shown in Table 32. A photovoltaic element for comparison was produced by exactly the same operation and method except that an A-Si film, an A-SiC film, and an A-SiGe film produced under the indicated film forming conditions were used. .28,29,30. Table 31 shows the measurement results of the solar cell characteristics and the like.

Comparative Example 5 In the triple-type photovoltaic element 120 of Example 23, only the p-type semiconductor layer 119 of the third-layer photovoltaic element 113 was replaced with the BAs: H: F film of the present invention in Comparative Example 1. A photovoltaic device for comparison having exactly the same configuration as that of the photovoltaic device except that the film was changed to a p-type A-Si: H: F film was prepared, and was designated as device No. 31. Table 30 shows the measurement results of the solar cell characteristics and the like.

(Results of Characteristic Evaluation of Each Sample) The measurement results of the solar cell characteristics and the like of the respective elements manufactured in Examples 1 to 23 and Comparative Examples 1 to 5 are ninth, 17, 27, 30, and 3
Shown in Table 1.

The characteristic evaluation items for the photovoltaic element were AM-1 light (10
0mW / cm ² ) Open-circuit voltage (Voc), short-circuit current (Is
c), there is a relative value of the output of each element under AM-1 irradiation transmitted through a 400 nm interference filter (relative value to the output of the element manufactured in Comparative Example 1 under the same conditions). The evaluation results are shown.

Further, the p-type and / or n-type BAs: H (F) film used to constitute each photovoltaic element may have the content of hydrogen atom and fluorine atom and the average crystal grain size specified in the present invention. Each of p-type and / or n-type BAs: H (F) films prepared for confirming whether or not the composition ratio of B atoms and As atoms satisfies the stoichiometric ratio Of hydrogen atom and fluorine atom, average crystal grain size, B atom and As
The measured value of the composition ratio with atoms is also shown.

Summarizing the above results, in the pin heterojunction photovoltaic devices of Examples 1 to 3, the A-Si: H: F film was used as the n-type semiconductor layer and the i-type semiconductor layer, and the p-type semiconductor layer was Using a BAs: H: (F) film in which the content of hydrogen atoms and fluorine atoms and the average crystal grain size in the film of the present invention are controlled to specific ranges, and forming the BAs: H (F) film Although examples in which the method is variously changed are shown, A is added to the p-type semiconductor layer shown in Comparative Example 1.
-Higher open-circuit voltage Voc, higher short-circuit photocurrent Isc, and higher relative output under AM-1 light irradiation through a 400 nm interference filter than photovoltaic devices using Si: H: F. Was found to be a photovoltaic element.

In the fourth embodiment, as the i-type semiconductor layer 104,
The A-SiC: H: F film is used as the i-type semiconductor layer 104 in the fifth embodiment.
In the sixth embodiment, an A-SiGe: H: F film is used. In the sixth embodiment, a poly-Si: H: F film is used as the i-type semiconductor layer 104. did. In each case, although it varied depending on the band gap of the i-type semiconductor layer, it was found that the photovoltaic device was an excellent photovoltaic device having a high Voc or a large Isc as a whole.

In Example 7, a photovoltaic element having a configuration shown in FIG. 1B using a glass substrate was used, and light was incident from the glass substrate side. However, similar to Examples 1 to 3, excellent solar cell characteristics were obtained. was gotten.

In Example 8, the BAs: H (F) film of the present invention was used for the n-type semiconductor layer 103 simultaneously with the p-type semiconductor layer 105, but excellent solar cell characteristics were obtained as in Examples 1 to 3. Was done.

On the other hand, the photovoltaic element manufactured in Comparative Example 2 has p
Where the type semiconductor layer had a content of hydrogen atoms and fluorine atoms and a crystal grain size outside the range specified in the present invention,
Low Voc, low Isc, low relative output, Example 1
The solar cell characteristics were far inferior to those of the photovoltaic devices manufactured in Nos. 1 to 3.

In Comparative Example 3, BAs: H as a p-type semiconductor layer was used.
(F) When the composition ratio of B atoms and As atoms in the film did not satisfy the stoichiometric ratio, the solar cell characteristics were also inferior to those of the photovoltaic devices manufactured in Examples 1 to 3. I was

In Comparative Example 4, as the i-type semiconductor layer 104, an A-Si film containing no hydrogen atoms and no fluorine atoms, an A-SiC film, an AS
Despite the use of the iGe film and the use of the BAs: H (F) film specified in the present invention as the p-type semiconductor layer, the solar cell characteristics were far inferior to those of Examples 3 to 5. I was

In the ninth to twelfth embodiments, as the n-type semiconductor layer, BAs
Using a film, an A-SiGe: H: F film, an A-SiC: H: F film, and a GaAs film,
A photovoltaic element having the same other configuration as that of Example 1 was examined. In each case, although the band gap of the n-type semiconductor layer was slightly affected, excellent solar cell characteristics having a high Voc or a large Isc were obtained as a whole.

In Examples 13 to 18, a study was conducted in which the composition of the i-type semiconductor layer was changed in the photovoltaic device having the configuration implemented in Example 8. Specifically, A-Si: H film, A-SiGe: H film, A-Si
A photovoltaic element was manufactured using a C: H film, an A-Si: F film, an A-SiGeC: H film, and a poiy-Si: H film. In any case, although there is a change according to the magnitude of the band gap of the i-type semiconductor layer, overall
Excellent solar cell characteristics with high Voc or large Isc were obtained.

In Examples 19 to 22, the photovoltaic element having the configuration shown in FIG. 1B is used. However, the stacking positions of the p-type semiconductor layer and the n-type semiconductor layer are switched, and light is incident from the n-type semiconductor layer side. went. Here, the BAs: H (F) film of the present invention is used for the n-type semiconductor layer, the A-Si: H: F film is used for the i-type semiconductor layer, and those having different compositions are used for the p-type semiconductor layer. Was. Specifically, A-
The Si: H: F film, the A-SiC: H: F film, the ZnTe film, and the BAs film were examined.Although the effect of the band gap of the p-type semiconductor layer was slightly affected, Voc was generally high, or Excellent solar cell characteristics with large Isc were obtained.

The characteristic evaluation item as a photovoltaic element in Example 23 and Comparative Example 5 was Vo under irradiation with AM-1 light (100 mW / cm ² ).
The amount of change in photoelectric conversion efficiency before and after continuous irradiation of c, Isc and AM-1 light for 10 hours (Δη / η ₀ : Δη indicates the amount of change in photoelectric conversion efficiency, η ₀ indicates the initial photoelectric conversion efficiency), The results of these evaluations are shown in Table 30.

From the above results, the BAs: H of the present invention was added to the p-type semiconductor layer.
The triple-structure photovoltaic element of Example 23 using the (F) film is different from the triple-structure photovoltaic element of Comparative Example 5 using the A-Si: H: F film for the p-type semiconductor layer. Both Voc and Isc were found to be excellent. Regarding the amount of change in photoelectric conversion efficiency, the photovoltaic element in Example 23 is smaller than that in Comparative Example 5. Generally, the degradation phenomenon of photoelectric conversion efficiency is
It occurs remarkably within 10 hours after the start of continuous irradiation of light,
Since the subsequent change is extremely slow, the photovoltaic element in Example 23 having a small change rate in continuous 10-hour light irradiation has not only excellent initial characteristics but also can be used for a long time. It was found that the photovoltaic element was highly practical as a solar cell.

[Summary of Effects of the Invention] As described above, the photovoltaic device of the present invention has a high photoelectric conversion efficiency of short wavelength light, and can extract a large short-circuit current (Isc) with a high open-circuit voltage (Voc). In addition, a more inexpensive substrate can be used, and the stacked type can extremely reduce the characteristic deterioration due to use, so that it can be highly practical as a solar cell for a power supply system. .

[Brief description of the drawings]

FIGS. 1A and 1B are schematic cross-sectional views of a typical example of a layer configuration of a photovoltaic device of the present invention. Fig. 1 (C)
FIG. 1 is a schematic sectional view of a layer structure of a stacked photovoltaic device of the present invention. FIG. 2 is a schematic diagram of an example of a deposited film forming apparatus for performing the HRCVD method of the present invention. FIG. 3 is a schematic diagram of an example of a deposited film forming apparatus for performing the reactive sputtering method of the present invention. FIG. 4 is a schematic diagram of an example of a deposited film forming apparatus for performing the plasma CVD method of the present invention. 1, 100, 111, 112, 113 ... photovoltaic element, 101 ... support, 102 ...
Lower electrode, 103, 114 ... n-type semiconductor layer, 104, 115, 118 ... i-type semiconductor layer, 105, 116, 119 ... p-type semiconductor layer, 106 ... transparent electrode, 107 ... current collecting electrode. 2, 3, and 4, 201, 301, 401: film forming chamber, 202, 302, 402: substrate holding cassette, 203, 303, 403: substrate, 204, 304, 404: thermocouple, 205, 30
5,405: heater, 206, 306, 406: substrate transfer jig, 207, 30
7,407… Gate valve, 308,408,409… Gas inlet pipe, 208,
209,210… Activation chamber, 211,212,213… Excitation energy generator, 214,215,216… Gas supply pipe, 212,313,413… Load lock chamber, 217,218,219… Transport pipe, 220,314,414… Valve, 221,315,415… Exhaust pump, 222,316,416… Other film formation chamber, 223,309,417… Pressure Total, 310,410… High frequency power supply, 31
1,411 matching circuit, 312,412 cathode electrode, 317
…target.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Soichiro Kawakami 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-56-11667 (JP, A) -151374 (JP, A) JP-A-55-124272 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 31/04

Claims (3)

(57) [Claims] 1. A photovoltaic device having a junction structure of a p-type semiconductor layer, an i-type semiconductor layer, and an n-type semiconductor layer, wherein at least the p-type semiconductor layer or the n-type semiconductor layer of the semiconductor layers is provided. Is a polycrystalline BAs thin film having an average crystal grain size of 50 to 800 ° containing a hydrogen atom and / or a fluorine atom and a p-type or n-type valence electron controlling atom, and the content of the hydrogen atom Is 0.5 to 6 atomic%, and
A photovoltaic element, wherein the type semiconductor layer is made of a non-single-crystal silicon semiconductor containing hydrogen atoms and / or fluorine atoms. 2. A photovoltaic device having a junction structure of a p-type semiconductor layer, an i-type semiconductor layer, and an n-type semiconductor layer, wherein at least the p-type semiconductor layer or the n-type semiconductor layer of the semiconductor layers is provided. Is a polycrystalline BAs thin film having an average crystal grain size of 50 to 800 ° containing a hydrogen atom and / or a fluorine atom and a p-type or n-type valence electron controlling atom, and the content of the hydrogen atom Is 0.5 to 6 atomic%, and
The type semiconductor layer comprises germanium atoms and / or carbon atoms,
A photovoltaic element comprising a non-single-crystal silicon alloy-based semiconductor containing hydrogen atoms and / or fluorine atoms. 3. The photovoltaic device according to claim 1, wherein at least one of the p-type semiconductor layer and the n-type semiconductor layer contains 4 atomic% or less of fluorine atoms.