WO2011105166A1 - 光電変換モジュール及びその製造方法 - Google Patents

光電変換モジュール及びその製造方法 Download PDF

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WO2011105166A1
WO2011105166A1 PCT/JP2011/051729 JP2011051729W WO2011105166A1 WO 2011105166 A1 WO2011105166 A1 WO 2011105166A1 JP 2011051729 W JP2011051729 W JP 2011051729W WO 2011105166 A1 WO2011105166 A1 WO 2011105166A1
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layer
type layer
photoelectric conversion
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conversion device
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松本　光弘
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三洋電機株式会社
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Definitions

  • the present invention relates to a photoelectric conversion module and a manufacturing method thereof.
  • Solar cells using polycrystalline, microcrystalline, or amorphous silicon are known.
  • a photoelectric conversion device having a structure in which microcrystalline or amorphous silicon thin films are stacked has attracted attention from the viewpoint of resource consumption, cost reduction, and efficiency.
  • a photoelectric conversion device is formed by sequentially stacking a first electrode, one or more semiconductor thin film photoelectric conversion cells, and a second electrode on a substrate having an insulating surface.
  • Each photoelectric conversion unit is configured by stacking a p-type layer, an i-type layer, and an n-type layer from the light incident side.
  • As a method for improving the conversion efficiency of a photoelectric conversion device it is known to stack two or more types of photoelectric conversion cells in the light incident direction.
  • a first photoelectric conversion unit including a photoelectric conversion layer having a wide band gap is disposed on the light incident side of the photoelectric conversion device, and then a second photoelectric conversion layer including a photoelectric conversion layer having a narrower band gap than the first photoelectric conversion unit is disposed.
  • a photoelectric conversion unit is arranged. Thereby, photoelectric conversion can be performed over a wide wavelength range of incident light, and the conversion efficiency of the entire apparatus can be improved.
  • a structure in which an amorphous silicon (a-Si) photoelectric conversion unit is a top cell and a microcrystalline silicon ( ⁇ c-Si) photoelectric conversion unit is a bottom cell is known.
  • an intervening layer is provided at the interface between the p-type layer and the i-type layer of the ⁇ c-Si photoelectric conversion unit.
  • the intervening layer is made of microcrystalline silicon and is a layer having a thickness of 10 to 150 mm and containing 1 ⁇ 10 20 atoms / cm 3 or more of impurities such as carbon that increase the band gap of the amorphous silicon component (for example, Patent Document 1). reference).
  • a low density region in which the density of the group IV element as a main component is reduced is discretely formed in the formation surface of the i type semiconductor layer in the vicinity of the interface between the doping layer and the i type layer.
  • the group IV element as the main component is silicon
  • a technique for increasing photoelectric conversion efficiency by laminating a silicon germanium (SiGe) layer and a silicon layer as an i-type layer in the ⁇ c-Si photoelectric conversion unit.
  • the SiGe layer is preferably a relatively thick layer of 25 nm to 200 nm (see, for example, Patent Document 3).
  • the open crystal voltage is about 0.5 V because the microcrystalline silicon layer includes an amorphous phase rather than a complete crystalline phase.
  • the open crystal voltage is significantly lower than a photoelectric conversion device having a power generation layer.
  • Patent Documents 1 and 2 in a photoelectric conversion device of a type in which an n-type layer, an i-type layer, and a p-type layer are formed in this order on a substrate and light is incident from the opposite side to the substrate, Data is described about a structure in which an i-type layer of microcrystalline silicon carbide is sandwiched as an interface layer having a thickness of 40 nm or less.
  • a photoelectric conversion device of a type in which a p-type layer, an i-type layer, and an n-type layer are formed on a substrate and light is incident from the substrate side has a difference in the growth direction of microcrystals, and a sufficient effect is obtained. There wasn't.
  • Patent Document 3 a laminated structure of a microcrystalline silicon germanium layer and a microcrystalline silicon layer is disclosed, but an i-type layer is configured by a laminated structure of a microcrystalline silicon carbide layer and a microcrystalline silicon layer. The technology to do is not disclosed.
  • One embodiment of the present invention is a photoelectric conversion device including a stacked structure of a p-type layer including a p-type dopant, an i-type layer including a microcrystalline silicon layer serving as a power generation layer, and an n-type layer including an n-type dopant.
  • the i-type layer is a photoelectric conversion device including a microcrystalline silicon carbide layer provided between the p-type layer and the n-type layer and having a thickness of 50 nm to 300 nm.
  • Another embodiment of the present invention is to manufacture a photoelectric conversion device having a stacked structure of a p-type layer containing a p-type dopant, an i-type layer containing a microcrystalline silicon layer to be a power generation layer, and an n-type layer containing an n-type dopant.
  • a method for manufacturing a photoelectric conversion device wherein a microcrystalline silicon carbide layer having a thickness of 50 nm to 300 nm is formed between a p-type layer and an n-type layer.
  • the photoelectric conversion efficiency in the photoelectric conversion device can be improved.
  • FIG. 1 is a cross-sectional view showing the structure of a photoelectric conversion device 100 according to an embodiment of the present invention.
  • the transparent insulating substrate 10 is a light incident side, the transparent conductive film 12 from the light incident side, and amorphous silicon (a-Si) having a wide band gap as a top cell (photoelectric conversion) Unit 102, intermediate layer 14, microcrystalline silicon ( ⁇ c-Si) (photoelectric conversion) unit 104 having a narrower band gap than a-Si unit 102 as a bottom cell, first back electrode layer 16, second back electrode layer 18, filler 20 and a protective film 22 are stacked.
  • a-Si amorphous silicon having a wide band gap as a top cell (photoelectric conversion) Unit 102
  • ⁇ c-Si microcrystalline silicon
  • the transparent insulating substrate 10 for example, a material having transparency in at least a visible light wavelength region such as a glass substrate or a plastic substrate can be applied.
  • a transparent conductive film 12 is formed on the transparent insulating substrate 10.
  • the transparent conductive film 12 is doped with tin oxide (SnO 2 ), zinc oxide (ZnO), indium tin oxide (ITO), etc. with tin (Sn), antimony (Sb), fluorine (F), aluminum (Al), etc. It is preferable to use at least one or a combination of a plurality of transparent conductive oxides (TCO).
  • zinc oxide (ZnO) is preferable because it has high translucency, low resistivity, and excellent plasma resistance.
  • the transparent conductive film 12 can be formed by, for example, sputtering.
  • the film thickness of the transparent conductive film 12 is preferably in the range of 0.5 ⁇ m to 5 ⁇ m. Moreover, it is preferable to provide unevenness having a light confinement effect on the surface of the transparent conductive film 12.
  • an a-Si unit 102 is formed by sequentially laminating a p-type layer, an i-type layer, and an n-type silicon thin film.
  • the a-Si unit 102 includes silicon-containing gas such as silane (SiH 4 ), disilane (Si 2 H 6 ), dichlorosilane (SiH 2 Cl 2 ), carbon-containing gas such as methane (CH 4 ), diborane (B 2 H 6 ) etc., formed by plasma CVD in which a mixed gas obtained by mixing a p-type dopant containing gas such as phosphine (PH 3 ) and a diluted gas such as phosphine (PH 3 ) and a diluent gas such as hydrogen (H 2 ) is formed into a plasma.
  • silicon-containing gas such as silane (SiH 4 ), disilane (Si 2 H 6 ), dichlorosilane (SiH 2 Cl 2 ), carbon-containing gas such as methan
  • the RF plasma CVD can be a parallel plate type. It is good also as a structure which provided the gas shower hole for supplying the mixed gas of a raw material in the side which does not arrange
  • the plasma input power density is preferably 5 mW / cm 2 or more and 100 mW / cm 2 or less.
  • the p-type layer, i-type layer, and n-type layer are formed in separate film formation chambers.
  • the film forming chamber can be evacuated by a vacuum pump and has an electrode for RF plasma CVD.
  • a transfer device for the transparent insulating substrate 10, a power source and matching device for RF plasma CVD, piping for gas supply, and the like are attached.
  • the p-type layer is formed on the transparent conductive film 12.
  • the p-type layer is a p-type amorphous silicon layer (p-type ⁇ -Si: H) or p-type amorphous silicon carbide (p-type ⁇ -SiC: H) having a thickness of 10 nm to 100 nm doped with a p-type dopant (boron or the like). ).
  • the film quality of the p-type layer can be changed by adjusting the mixing ratio of the silicon-containing gas, the carbon-containing gas, the p-type dopant-containing gas and the dilution gas, the pressure, and the high frequency power for plasma generation.
  • the i-type layer is an undoped amorphous silicon film of 50 nm to 500 nm formed on the p-type layer.
  • the film quality of the i-type layer can be changed by adjusting the mixing ratio of the silicon-containing gas and the dilution gas, the pressure, and the high frequency power for plasma generation.
  • the i-type layer serves as a power generation layer of the a-Si unit 102.
  • the n-type layer is an n-type amorphous silicon layer (n-type ⁇ -Si: H) having a thickness of 10 nm to 100 nm doped with an n-type dopant (such as phosphorus) formed on the i-type layer or n-type microcrystalline silicon.
  • the film quality of the n-type layer can be changed by adjusting the mixing ratio of the silicon-containing gas, the carbon-containing gas, the n-type dopant-containing gas and the dilution gas, the pressure, and the high-frequency power for plasma generation.
  • the intermediate layer 14 is formed on the a-Si unit 102.
  • the intermediate layer 14 is preferably made of a transparent conductive oxide (TCO) such as zinc oxide (ZnO) or silicon oxide (SiOx). In particular, it is preferable to use zinc oxide (ZnO) or silicon oxide (SiOx) doped with magnesium Mg.
  • TCO transparent conductive oxide
  • ZnO zinc oxide
  • SiOx silicon oxide
  • the intermediate layer 14 can be formed by, for example, sputtering.
  • the film thickness of the intermediate layer 14 is preferably in the range of 10 nm to 200 nm. The intermediate layer 14 need not be provided.
  • the ⁇ c-Si unit 104 includes a silicon-containing gas such as silane (SiH 4 ), disilane (Si 2 H 6 ), dichlorosilane (SiH 2 Cl 2 ), a carbon-containing gas such as methane (CH 4 ), diborane (B 2 H 6 ) etc., formed by plasma CVD in which a mixed gas obtained by mixing a p-type dopant containing gas such as phosphine (PH 3 ) and a diluted gas such as phosphine (PH 3 ) and a diluent gas such as hydrogen (H 2 ) is formed into a plasma.
  • a silicon-containing gas such as silane (SiH 4 ), disilane (Si 2 H 6 ), dichlorosilane (SiH 2 Cl 2 ), a carbon-containing gas such as methane (CH 4 ), diborane (B 2 H 6 ) etc.
  • RF plasma CVD for example, RF plasma CVD of 13.56 MHz or 27.12 MHz is preferably applied. In particular, it is preferable to apply 13.56 MHz RF plasma CVD to the p-type layer 40 and the n-type layer 44 and 27.12 MHz RF plasma CVD to the i-type layer 42.
  • the RF plasma CVD can be a parallel plate type. It is good also as a structure which provided the gas shower hole for supplying the mixed gas of a raw material in the side which does not arrange
  • the plasma input power density is preferably 5 mW / cm 2 or more and 100 mW / cm 2 or less.
  • the p-type layer 40 is formed on the intermediate layer 14 or the n-type layer of the ⁇ -Si unit 102.
  • the p-type layer 40 is preferably a microcrystalline silicon ( ⁇ c-Si) layer or a microcrystalline silicon carbide ( ⁇ c-SiC) layer.
  • the p-type layer 40 may be an amorphous layer such as an amorphous silicon ( ⁇ -Si) layer.
  • the p-type layer 40 is preferably doped with a p-type dopant (boron or the like) to have a film thickness of 5 nm to 50 nm.
  • the film quality of the p-type layer 40 can be changed by adjusting the mixing ratio of the silicon-containing gas, the carbon-containing gas, the p-type dopant-containing gas and the dilution gas, the pressure, and the high frequency power for plasma generation.
  • the i-type layer 42 is formed on the p-type layer 40.
  • the i-type layer 42 is an undoped microcrystalline silicon layer or microcrystalline silicon carbide layer formed on the p-type layer 40 and having a thickness of 0.5 ⁇ m to 5 ⁇ m.
  • the i-type layer 42 becomes a power generation layer of the ⁇ c-Si unit 104.
  • the i-type layer 42 forms a first i-type layer 42 a so as to be in contact with the p-type layer 40, and a second i-type layer 42 b is stacked on the first i-type layer 42 a. .
  • the first i-type layer 42a is an initial layer of the i-type layer 42, and is a microcrystalline silicon carbide ( ⁇ c-SiC) layer having a wider band gap than the second i-type layer 42b.
  • the first i-type layer 42a is a mixed gas obtained by diluting a source gas having a methane (CH 4 ) / silane (SiH 4 ) ratio of 1/10 to 1/6 with hydrogen (H 2 ) by 50 to 300 times. Is preferably introduced at a pressure of 133 Pa or more and 4000 Pa or less by a plasma film forming method.
  • the concentration of carbon contained in the first i-type layer 42a is preferably in the range of 1 ⁇ 10 21 / cm 3 to 3 ⁇ 10 21 / cm 3 .
  • the concentration of carbon contained in the first i-type layer 42a can be measured by measuring in the film thickness direction of the photoelectric conversion device 100 using a secondary ion analyzer.
  • As the plasma film formation method it is preferable to apply an RF plasma film formation method of 27.12 MHz to 60 MHz.
  • the substrate temperature during film formation was set to 0.99 ° C. or higher 230 ° C. or less, introducing power to the plasma is preferably set to 100 mW / cm 2 or more 2000 mW / cm 2 or less.
  • the second i-type layer 42b is a microcrystalline silicon ( ⁇ c-Si) layer that has a narrower band gap than the first i-type layer 42a.
  • the second i-type layer 42b is formed by introducing a mixed gas diluted with hydrogen (H 2 ) by 0.005 or more and 0.1 or less using silane (SiH 4 ) as a source gas at a pressure of 1330 Pa or more and 4000 Pa or less. It is preferable to form by a film method.
  • the plasma film formation method it is preferable to apply an RF plasma film formation method of 27.12 MHz to 60 MHz.
  • the substrate temperature during film formation set to 160 ° C. or higher 230 ° C. or less, introducing power to the plasma is preferably set to 100 mW / cm 2 or more 2000 mW / cm 2 or less.
  • the film thickness of the first i-type layer 42a is preferably 50 nm or more and 300 nm or less.
  • the film thickness of the first i-type layer 42a is less than 50 nm, sufficient improvement in the open-circuit voltage or short-circuit current of the photoelectric conversion device 100 cannot be obtained, and when the film thickness is greater than 300 nm, the i-type layer There is a possibility that the series resistance of 42 becomes too large and the short circuit current and the fill factor are lowered.
  • the i-type layer 42 includes a second i-type layer 42b that is in contact with the p-type layer 40, and the second i-type layer 42b is formed on the second i-type layer 42b.
  • One i-type layer 42a may be laminated. Thereby, a short circuit current can be improved.
  • the n-type layer 44 is formed on the i-type layer 42.
  • the n-type layer 44 is an n-type microcrystalline silicon layer (n-type ⁇ c-Si: H) doped with an n-type dopant (such as phosphorus) and having a thickness of 5 nm to 50 nm.
  • n-type dopant such as phosphorus
  • the ⁇ c-Si unit 104 is not limited to this, and any unit that uses an i-type microcrystalline silicon layer (i-type ⁇ c-Si: H) described below as a power generation layer may be used.
  • a laminated structure of a reflective metal and a transparent conductive oxide (TCO) is formed on the ⁇ c-Si unit 104 as the first back electrode layer 16 and the second back electrode layer 18.
  • a transparent conductive oxide (TCO) such as tin oxide (SnO 2 ), zinc oxide (ZnO), indium tin oxide (ITO), or the like is used.
  • the TCO can be formed by, for example, sputtering.
  • metals such as silver (Ag) and aluminum (Al), can be used.
  • the first back electrode layer 16 and the second back electrode layer 18 preferably have a thickness of about 1 ⁇ m in total. It is preferable that at least one of the first back electrode layer 16 and the second back electrode layer 18 is provided with unevenness for enhancing the light confinement effect.
  • the surface of the second back electrode layer 18 is covered with the protective film 22 with the filler 20.
  • the filler 20 and the protective film 22 can be made of a resin material such as EVA or polyimide. This can prevent moisture from entering the power generation layer of the photoelectric conversion device 100.
  • a YAG laser fundamental wave 1064nm, double wave 532nm.
  • Example 1 to 4 As the transparent insulating substrate 10, a 55 cm ⁇ 65 cm square, 4 mm thick glass substrate was used. On the transparent insulating substrate 10, 600 nm thick SnO 2 having a concavo-convex shape on the surface was formed as a transparent conductive film 12 by thermal CVD. Thereafter, the transparent conductive film 12 was patterned into strips with a YAG laser. A YAG laser having a wavelength of 1064 nm, an energy density of 13 J / cm 3 , and a pulse frequency of 3 kHz was used.
  • a p-type layer, an i-type layer, and an n-type layer of the ⁇ -Si unit 102 were sequentially laminated.
  • the p-type layer, i-type layer, and n-type layer of the a-Si unit 102 were formed under the film formation conditions shown in Table 1.
  • the ⁇ c-Si unit 104 was formed on the n-type layer of the ⁇ -Si unit 102.
  • the p-type layer 40, i-type layer 42, and n-type layer 44 of the ⁇ c-Si unit 104 were formed under the film formation conditions shown in Table 2.
  • the i-type layer 42 is formed by forming the first i-type layer 42a on the p-type layer 40 with a thickness of 50 nm, 100 nm, 200 nm, and 300 nm, and the first i-type layer 42a and the second i-type layer 42b.
  • the film thickness of the second i-type layer 42b was adjusted so that the total film thickness was 2 ⁇ m, and the film was formed on the first i-type layer 42a.
  • a YAG laser was irradiated to a position 50 ⁇ m lateral from the patterning position of the transparent conductive film 12, and the a-Si unit 102 and the ⁇ c-Si unit 104 were patterned into strips.
  • a ZnO film was formed as the first back electrode layer 16 by sputtering, and an Ag electrode was formed as the second back electrode layer 18 by sputtering.
  • a YAG laser was irradiated to a position 50 ⁇ m lateral from the patterning position of the a-Si unit 102 and the ⁇ c-Si unit 104, and the first back electrode layer 16 and the second back electrode layer 18 were patterned into strips.
  • a YAG laser having an energy density of 0.7 J / cm 3 and a pulse frequency of 4 kHz was used.
  • the photoelectric conversion devices formed in this way are referred to as Examples 1 to 4 with respect to the respective film thicknesses of the first i-type layer 42a.
  • a photoelectric conversion device in which the film thickness of the first i-type layer 42a is 10 nm and the film thickness of the second i-type layer 42b is 1600 nm under the same formation conditions as in Examples 1 to 4 is Comparative Example 2. It was. Further, a photoelectric conversion device in which the film thickness of the first i-type layer 42a is set to 400 nm and the film thickness of the second i-type layer 42b is set to 1600 nm under the same formation conditions as in Examples 1 to 4 is shown in Comparative Example 3. It was.
  • Example 5 A photoelectric conversion device in which the film formation order of the first i-type layer 42a and the second i-type layer 42b was reversed under the same formation conditions as in Examples 1 to 4 was referred to as Example 5. That is, after the second i-type layer 42b was formed on the p-type layer 40, the first i-type layer 42a was formed on the second i-type layer 42b. The film thickness of the second i-type layer 42b was 1.9 ⁇ m, and the film thickness of the first i-type layer 42a was 0.1 ⁇ m.
  • Example 6 Under the same formation conditions as in Example 2 above, the methane (CH 4 ) / silane (SiH 4 ) ratio contained in the source gas when forming the first i-type layer 42a is changed to change the first i-type layer.
  • Examples 6 and 7 were photoelectric conversion devices formed so that the concentration of carbon contained in 42a was 1 ⁇ 10 21 / cm 3 and 3 ⁇ 10 21 / cm 3 , respectively.
  • Table 3 shows the open circuit voltage Voc, the short circuit current density Jsc, the fill factor FF, and the efficiency ⁇ of the photoelectric conversion devices of Examples 1 to 4 and Comparative Examples 1 to 3.
  • the measured values of Examples 1 to 4 are normalized and shown with the average values of open circuit voltage Voc, short circuit current density Jsc, fill factor FF and efficiency ⁇ of Comparative Example 1 being 1, respectively.
  • Example 1 the open circuit voltage Voc did not increase, but the short circuit current density Jsc increased and the conversion efficiency ⁇ improved by 2.5%.
  • Example 2 to 4 the open circuit voltage Voc and the short-circuit current density Jsc increased, and the conversion efficiency ⁇ improved by 4.0%, 3.7%, and 2.4%, respectively.
  • the decrease in the fill factor FF was small with respect to the increase in the open circuit voltage Voc and the short circuit current density Jsc, and the conversion efficiency ⁇ was improved.
  • Comparative Example 2 in which the first i-type layer 42a was 10 nm, most of the parameters were not changed, and almost the same as when there was no first i-type layer 42a.
  • Comparative Example 3 in which the first i-type layer 42a was 400 nm, the decrease in the fill factor FF was large, and the conversion efficiency ⁇ was smaller than that in Comparative Example 1.
  • Example 5 the short-circuit current density Jsc increased by 2% compared to Comparative Example 1.
  • the open circuit voltage Voc is obtained.
  • the decrease in the fill factor FF can be suppressed while increasing the short-circuit current density Jsc, and the photoelectric conversion efficiency ⁇ of the photoelectric conversion device 100 can be improved.
  • tandem structure of the amorphous silicon photoelectric conversion unit 102 and the microcrystalline silicon photoelectric conversion unit 104 is described as an example; however, the present invention is not limited to this, and the microcrystalline silicon photoelectric conversion unit 104 A single structure may be used, a laminated structure with photoelectric conversion units other than the amorphous silicon photoelectric conversion unit 102, or a laminated structure of three or more photoelectric conversion units.

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Abstract

【課題】微結晶シリコン層を発電層として含む光電変換装置において、フィルファクタを 低下させることなく、開放電圧を向上させる。 【解決手段】ｐ型ドーパントを含むｐ型層４０、発電層となる微結晶シリコン層を含むｉ 型層４２及びｎ型ドーパントを含むｎ型層４４の積層構造を備え、ｉ型層４２は、ｐ型層 ４０とｎ型層４４との間に設けられ、５０ｎｍ以上３００ｎｍ以下の膜厚を有する微結晶 炭化シリコン層４２ａを備える構造とする。

Description

光電変換モジュール及びその製造方法
　本発明は、光電変換モジュール及びその製造方法に関する。
　多結晶、微結晶またはアモルファスシリコンを用いた太陽電池が知られている。特に、微結晶またはアモルファスシリコンの薄膜を積層した構造を有する光電変換装置は、資源消費の観点、コストの低下の観点および効率化の観点から注目されている。
　一般的に、光電変換装置は、表面が絶縁性の基板上に第１電極、１以上の半導体薄膜光電変換セル及び第２電極を順に積層して形成される。それぞれの光電変換ユニットは、光入射側からｐ型層、ｉ型層及びｎ型層を積層して構成される。光電変換装置の変換効率を向上させる方法として、２種以上の光電変換セルを光入射方向に積層することが知られている。光電変換装置の光入射側にはバンドギャップが広い光電変換層を含む第１の光電変換ユニットを配置し、その後に第１の光電変換ユニットよりもバンドギャップの狭い光電変換層を含む第２の光電変換ユニットを配置する。これにより、入射光の広い波長範囲に亘って光電変換を可能にし、装置全体として変換効率の向上を図ることができる。例えば、アモルファスシリコン（ａ－Ｓｉ）光電変換ユニットをトップセルとし、微結晶シリコン（μｃ－Ｓｉ）光電変換ユニットをボトムセルとした構造が知られている。
　このような構造において、μｃ－Ｓｉ光電変換ユニットのｐ型層とｉ型層との界面に介在層を設ける構成が開示されている。介在層としては、微結晶シリコンからなり、アモルファスシリコン成分のバンドギャップを増加させる炭素等の不純物を１×１０２０原子／ｃｍ３以上含む膜厚１０～１５０Åの層としている（例えば、特許文献１参照）。また、μｃ－Ｓｉ光電変換ユニットにおけるドーピング層とｉ型層との界面近傍のｉ型半導体層の形成面内に、主成分であるＩＶ属元素の密度が小さくなっている低密度領域を離散的に存在させる技術も開示されている。主成分であるＩＶ属元素がシリコンである場合、低密度領域には水素、炭素、窒素、酸素等を含有した膜厚３ｎｍ以上４０ｎｍ以下の層を適用することが好ましいとされている（例えば、特許文献２参照）。また、μｃ－Ｓｉ光電変換ユニットにおけるｉ型層としてシリコンゲルマニウム（ＳｉＧｅ）層とシリコン層とを積層させることにより光電変換効率を高める技術が開示されている。ＳｉＧｅ層は、２５ｎｍ以上２００ｎｍ以下と比較的厚い層とすることが好適であるとされている（例えば、特許文献３参照）。
特開２００３－２５８２８６号公報 特開平１１－２６１０８７号公報 特開２００６－１００６１１号公報
　微結晶シリコン層を発電層とするμｃ－Ｓｉ光電変換ユニットを含む光電変換装置では、微結晶シリコン層が完全な結晶相ではなくアモルファス相を含むために開放電圧が０．５Ｖ程度と結晶シリコン層を発電層とする光電変換装置よりも大幅に低くなるという問題がある。
　上記特許文献1及び２には、基板上にｎ型層、ｉ型層、ｐ型層の順に形成され、基板と逆側から光を入射するタイプの光電変換装置において、ｐ型層と界面に膜厚４０ｎｍ以下の界面層として微結晶炭化シリコンのｉ型層を挟み込んだ構造についてデータが記載されている。しかし、基板上にｐ型層、ｉ型層、ｎ型層と形成され、基板側から光を入射するタイプの光電変換装置では、微結晶の成長方向の違いもあり、充分な効果が得られなかった。また、上記特許文献３では、微結晶シリコンゲルマニウム層と微結晶シリコン層との積層構造については開示されているが、微結晶炭化シリコン層と微結晶シリコン層との積層構造によってｉ型層を構成する技術は開示されていない。
　そこで、フィルファクタを低下させることなく開放電圧を向上させた光電変換装置を提供することが課題となっている。
　本発明の１つの態様は、ｐ型ドーパントを含むｐ型層、発電層となる微結晶シリコン層を含むｉ型層及びｎ型ドーパントを含むｎ型層の積層構造を備えた光電変換装置であって、ｉ型層は、ｐ型層とｎ型層との間に設けられ、５０ｎｍ以上３００ｎｍ以下の膜厚を有する微結晶炭化シリコン層を備える、光電変換装置である。
　本発明の別の態様は、ｐ型ドーパントを含むｐ型層、発電層となる微結晶シリコン層を含むｉ型層及びｎ型ドーパントを含むｎ型層の積層構造を備えた光電変換装置の製造方法であって、ｐ型層とｎ型層との間に、５０ｎｍ以上３００ｎｍ以下の膜厚を有する微結晶炭化シリコン層を形成する、光電変換装置の製造方法である。
　本発明によれば、光電変換装置における光電変換効率を向上させることができる。
本発明の実施の形態における光電変換装置の構成を示す図である。 本発明の実施の形態における光電変換装置のμｃ－Ｓｉユニットの構成を示す図である。 本発明の実施の形態における光電変換装置のμｃ－Ｓｉユニットの構成を示す図である。
　図１は、本発明の実施の形態における光電変換装置１００の構造を示す断面図である。本実施の形態における光電変換装置１００は、透明絶縁基板１０を光入射側として、光入射側から、透明導電膜１２、トップセルとして広いバンドギャップを有するアモルファスシリコン（ａ－Ｓｉ）（光電変換）ユニット１０２、中間層１４、ボトムセルとしてａ－Ｓｉユニット１０２よりバンドギャップの狭い微結晶シリコン（μｃ－Ｓｉ）（光電変換）ユニット１０４、第１裏面電極層１６、第２裏面電極層１８、充填材２０及び保護膜２２を積層した構造を有している。
　以下、本発明の実施の形態における光電変換装置１００の構成及び製造方法について説明する。
　透明絶縁基板１０は、例えば、ガラス基板、プラスチック基板等の少なくとも可視光波長領域において透過性を有する材料を適用することができる。透明絶縁基板１０上に透明導電膜１２が形成される。透明導電膜１２は、酸化錫（ＳｎＯ２）、酸化亜鉛（ＺｎＯ）、インジウム錫酸化物（ＩＴＯ）等に錫（Ｓｎ）、アンチモン（Ｓｂ）、フッ素（Ｆ）、アルミニウム（Ａｌ）等をドープした透明導電性酸化物（ＴＣＯ）のうち少なくとも一種類又は複数種を組み合わせて用いることが好適である。特に、酸化亜鉛（ＺｎＯ）は、透光性が高く、抵抗率が低く、耐プラズマ特性にも優れているので好適である。透明導電膜１２は、例えば、スパッタリング等により形成することができる。透明導電膜１２の膜厚は０．５μｍ以上５μｍ以下の範囲とすることが好適である。また、透明導電膜１２の表面には光閉じ込め効果を有する凹凸を設けることが好適である。
　透明導電膜１２上に、ｐ型層、ｉ型層、ｎ型層のシリコン系薄膜を順に積層してａ－Ｓｉユニット１０２を形成する。ａ－Ｓｉユニット１０２は、シラン（ＳｉＨ４）、ジシラン（Ｓｉ２Ｈ６）、ジクロルシラン（ＳｉＨ２Ｃｌ２）等のシリコン含有ガス、メタン（ＣＨ４）等の炭素含有ガス、ジボラン（Ｂ２Ｈ６）等のｐ型ドーパント含有ガス、フォスフィン（ＰＨ３）等のｎ型ドーパント含有ガス及び水素（Ｈ２）等の希釈ガスを混合した混合ガスをプラズマ化して成膜を行うプラズマＣＶＤにより形成することができる。
　プラズマＣＶＤは、例えば、１３．５６ＭＨｚのＲＦプラズマＣＶＤを適用することが好適である。ＲＦプラズマＣＶＤは平行平板型とすることができる。平行平板型の電極のうち透明絶縁基板１０を配しない側には原料の混合ガスを供給するためのガスシャワー孔を設けた構成としてもよい。プラズマの投入電力密度は、５ｍＷ／ｃｍ２以上１００ｍＷ／ｃｍ２以下とすることが好ましい。
　一般的に、ｐ型層、ｉ型層、ｎ型層はそれぞれ別の成膜室において成膜される。成膜室は、真空ポンプによって真空排気可能であり、ＲＦプラズマＣＶＤのための電極が内蔵される。また、透明絶縁基板１０の搬送装置、ＲＦプラズマＣＶＤのための電源及びマッチング装置、ガス供給用の配管等が付設される。
　ｐ型層は、透明導電膜１２上に形成される。ｐ型層は、ｐ型ドーパント（ボロン等）をドープした膜厚１０ｎｍ以上１００ｎｍ以下のｐ型アモルファスシリコン層（ｐ型α－Ｓｉ：Ｈ）又はｐ型アモルファス炭化シリコン（ｐ型α－ＳｉＣ：Ｈ）とする。ｐ型層の膜質は、シリコン含有ガス、炭素含有ガス、ｐ型ドーパント含有ガス及び希釈ガスの混合比、圧力及びプラズマ発生用高周波パワーを調整することによって変化させることができる。ｉ型層は、ｐ型層上に形成されたドープされていない膜厚５０ｎｍ以上５００ｎｍ以下のアモルファスシリコン膜とする。ｉ型層の膜質は、シリコン含有ガス及び希釈ガスの混合比、圧力及びプラズマ発生用高周波パワーを調整することによって変化させることができる。また、ｉ型層は、ａ－Ｓｉユニット１０２の発電層となる。ｎ型層は、ｉ型層上に形成されたｎ型ドーパント（リン等）をドープした膜厚１０ｎｍ以上１００ｎｍ以下のｎ型アモルファスシリコン層（ｎ型α－Ｓｉ：Ｈ）又はｎ型微結晶シリコン層（ｎ型μｃ－Ｓｉ：Ｈ）とする。ｎ型層の膜質は、シリコン含有ガス、炭素含有ガス、ｎ型ドーパント含有ガス及び希釈ガスの混合比、圧力及びプラズマ発生用高周波パワーを調整することによって変化させることができる。
　ａ－Ｓｉユニット１０２上に、中間層１４を形成する。中間層１４は、酸化亜鉛（ＺｎＯ）、酸化シリコン（ＳｉＯｘ）等の透明導電性酸化物（ＴＣＯ）を用いることが好適である。特に、マグネシウムＭｇがドープされた酸化亜鉛（ＺｎＯ）や酸化シリコン（ＳｉＯｘ）を用いることが好適である。中間層１４は、例えば、スパッタリング等により形成することができる。中間層１４の膜厚は１０ｎｍ以上２００ｎｍ以下の範囲とすることが好適である。なお、中間層１４は、設けなくてもよい。
　中間層１４上に、図２の拡大断面図に示すように、ｐ型層４０、ｉ型層４２、ｎ型層４４を順に積層したμｃ－Ｓｉユニット１０４を形成する。μｃ－Ｓｉユニット１０４は、シラン（ＳｉＨ４）、ジシラン（Ｓｉ２Ｈ６）、ジクロルシラン（ＳｉＨ２Ｃｌ２）等のシリコン含有ガス、メタン（ＣＨ４）等の炭素含有ガス、ジボラン（Ｂ２Ｈ６）等のｐ型ドーパント含有ガス、フォスフィン（ＰＨ３）等のｎ型ドーパント含有ガス及び水素（Ｈ２）等の希釈ガスを混合した混合ガスをプラズマ化して成膜を行うプラズマＣＶＤにより形成することができる。
　プラズマＣＶＤは、例えば、１３．５６ＭＨｚ又は２７．１２ＭＨｚのＲＦプラズマＣＶＤを適用することが好適である。特に、ｐ型層４０及びｎ型層４４には１３．５６ＭＨｚのＲＦプラズマＣＶＤを適用し、ｉ型層４２には２７．１２ＭＨｚのＲＦプラズマＣＶＤを適用することが好適である。ＲＦプラズマＣＶＤは平行平板型とすることができる。平行平板型の電極のうち透明絶縁基板１０を配しない側には原料の混合ガスを供給するためのガスシャワー孔を設けた構成としてもよい。プラズマの投入電力密度は、５ｍＷ／ｃｍ２以上１００ｍＷ／ｃｍ２以下とすることが好ましい。
　ｐ型層４０は、中間層１４又はα－Ｓｉユニット１０２のｎ型層上に形成される。ｐ型層４０は、微結晶シリコン（μｃ－Ｓｉ）層や微結晶炭化シリコン（μｃ－ＳｉＣ）層とすることが好適である。また、ｐ型層４０は、アモルファスシリコン（α－Ｓｉ）層等のアモルファス層としてもよい。ｐ型層４０は、ｐ型ドーパント（ボロン等）をドープし、膜厚５ｎｍ以上５０ｎｍ以下とすることが好適である。ｐ型層４０の膜質は、シリコン含有ガス、炭素含有ガス、ｐ型ドーパント含有ガス及び希釈ガスの混合比、圧力及びプラズマ発生用高周波パワーを調整することによって変化させることができる。
　ｐ型層４０上にはｉ型層４２を形成する。ｉ型層４２は、ｐ型層４０上に形成されたドープされていない膜厚０．５μｍ以上５μｍ以下の微結晶シリコン層又は微結晶炭化シリコン層とする。ｉ型層４２は、μｃ－Ｓｉユニット１０４の発電層となる。
　１つの実施の形態においてｉ型層４２は、ｐ型層４０に接するように第１のｉ型層４２ａを形成し、第１のｉ型層４２ａ上に第２のｉ型層４２ｂを積層する。
　第１のｉ型層４２ａは、ｉ型層４２の初期層となる層であり、第２のｉ型層４２ｂよりもワイドバンドギャップである微結晶炭化シリコン（μｃ－ＳｉＣ）層とする。第１のｉ型層４２ａは、メタン（ＣＨ４）／シラン（ＳｉＨ４）比が１／１０以上１／６以下の原料ガスを水素（Ｈ２）で５０以上３００以下倍に希釈した混合ガスを圧力１３３Ｐａ以上４０００Ｐａ以下で導入してプラズマ成膜法によって形成することが好適である。このような条件により、第１のｉ型層４２ａに含有される炭素の濃度は１×１０２１／ｃｍ３以上３×１０２１／ｃｍ３以下の範囲とすることが好適である。第１のｉ型層４２ａに含有される炭素の濃度は、二次イオン分析装置により光電変換装置１００の膜厚方向に測定することによって測定することができる。プラズマ成膜法としては、２７．１２ＭＨｚ以上６０ＭＨｚ以下のＲＦプラズマ成膜法を適用することが好適である。また、成膜時の基板温度は１５０℃以上２３０℃以下とし、プラズマに対する導入電力は１００ｍＷ／ｃｍ２以上２０００ｍＷ／ｃｍ２以下とすることが好適である。
　第２のｉ型層４２ｂは、第１のｉ型層４２ａよりもナローバンドギャップである微結晶シリコン（μｃ－Ｓｉ）層とする。第２のｉ型層４２ｂは、シラン（ＳｉＨ４）を原料ガスとして水素（Ｈ２）で０．００５以上０．１以下倍に希釈した混合ガスを圧力１３３０Ｐａ以上４０００Ｐａ以下で導入してプラズマ成膜法によって形成することが好適である。プラズマ成膜法としては、２７．１２ＭＨｚ以上６０ＭＨｚ以下のＲＦプラズマ成膜法を適用することが好適である。また、成膜時の基板温度は１６０℃以上２３０℃以下とし、プラズマに対する導入電力は１００ｍＷ／ｃｍ２以上２０００ｍＷ／ｃｍ２以下とすることが好適である。
　第１のｉ型層４２ａの膜厚は、５０ｎｍ以上３００ｎｍ以下とすることが好適である。ｐ型層４０との界面側に比較的厚いワイドバンドギャップの第１のｉ型層４２ａを設けることによって、フィルファクタを低下させることなくμｃ－Ｓｉユニット１０４の開放電圧を上昇させることができる。これによって、光電変換装置１００の光電変換効率を向上させることができる。第１のｉ型層４２ａの膜厚を５０ｎｍ未満とした場合には光電変換装置１００の開放電圧又は短絡電流の十分な向上が得られず、膜厚を３００ｎｍより大きくした場合にはｉ型層４２の直列抵抗が大きくなり過ぎて短絡電流やフィルファクタを低下させる可能性がある。
　なお、別の実施の形態においてｉ型層４２は、図３に示すように、ｐ型層４０に接するように第２のｉ型層４２ｂを形成し、第２のｉ型層４２ｂ上に第１のｉ型層４２ａを積層してもよい。これにより、短絡電流を向上させることができる。
　ｎ型層４４は、ｉ型層４２上に形成される。ｎ型層４４は、ｎ型ドーパント（リン等）をドープした膜厚５ｎｍ以上５０ｎｍ以下ｎ型微結晶シリコン層（ｎ型μｃ－Ｓｉ：Ｈ）とする。ただし、μｃ－Ｓｉユニット１０４はこれに限定されるものではなく、発電層として以下に説明するｉ型微結晶シリコン層（ｉ型μｃ－Ｓｉ：Ｈ）が用いられるものであればよい。
　μｃ－Ｓｉユニット１０４上に、第１裏面電極層１６、第２裏面電極層１８として反射性金属と透明導電性酸化物（ＴＣＯ）との積層構造を形成する。第１裏面電極層１６としては、酸化錫（ＳｎＯ２）、酸化亜鉛（ＺｎＯ）、インジウム錫酸化物（ＩＴＯ）等の透明導電性酸化物（ＴＣＯ）が用いられる。ＴＣＯは、例えば、スパッタリング等により形成することができる。また、第２裏面電極層１８としては、銀（Ａｇ）、アルミニウム（Ａｌ）等の金属が使用できる。第１裏面電極層１６及び第２裏面電極層１８は、合わせて１μｍ程度の膜厚とすることが好適である。第１裏面電極層１６及び第２裏面電極層１８の少なくとも一方には、光閉じ込め効果を高めるための凹凸が設けることが好適である。
　さらに、充填材２０によって第２裏面電極層１８の表面を保護膜２２で被う。充填材２０及び保護膜２２は、ＥＶＡ、ポリイミド等の樹脂材料とすることができる。これによって、光電変換装置１００の発電層への水分の侵入等を防ぐことができる。
　なお、ＹＡＧレーザ（基本波１０６４ｎｍ、２倍波５３２ｎｍ）を用いて、透明導電膜１２、ａ－Ｓｉユニット１０２、中間層１４、μｃ－Ｓｉユニット１０４、第１裏面電極層１６、第２裏面電極層１８の分離加工を行うことによって、複数のセルを直列に接続した構成にしてもよい。
＜実施例＞
　以下、本発明の実施例及び比較例を示す。
（実施例１～４）
　透明絶縁基板１０として、５５ｃｍ×６５ｃｍ角，４ｍｍ厚のガラス基板を用いた。透明絶縁基板１０上に、熱ＣＶＤにより透明導電膜１２として表面に凹凸形状を有する６００ｎｍ厚のＳｎＯ２を形成した。この後、透明導電膜１２をＹＡＧレーザにて短冊状にパターニングした。ＹＡＧレーザは、波長１０６４ｎｍ、エネルギー密度１３Ｊ／ｃｍ３、パルス周波数３ｋＨｚのものを用いた。
　次に、α－Ｓｉユニット１０２のｐ型層，ｉ型層及びｎ型層を順に積層した。ａ－Ｓｉユニット１０２のｐ型層，ｉ型層及びｎ型層は、表１に示す成膜条件において形成した。次に、α－Ｓｉユニット１０２のｎ型層上に、μｃ－Ｓｉユニット１０４を形成した。μｃ－Ｓｉユニット１０４のｐ型層４０，ｉ型層４２及びｎ型層４４は、表２に示す成膜条件において形成した。ｉ型層４２は、第１のｉ型層４２ａをｐ型層４０上に５０ｎｍ，１００ｎｍ，２００ｎｍ及び３００ｎｍの膜厚で形成し、第１のｉ型層４２ａと第２のｉ型層４２ｂの合計の膜厚が２μｍとなるように第２のｉ型層４２ｂの膜厚を調整して第１のｉ型層４２ａ上に形成した。
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
　この後、透明導電膜１２のパターンニング位置から５０μｍ横の位置にＹＡＧレーザを照射し、ａ－Ｓｉユニット１０２及びμｃ－Ｓｉユニット１０４を短冊状にパターニングした。ＹＡＧレーザは、エネルギー密度０．７Ｊ／ｃｍ３、パルス周波数３ｋＨｚのものを用いた。
　次に、第１裏面電極層１６としてＺｎＯ膜をスパッタリングにより形成し、第２裏面電極層１８としてＡｇ電極をスパッタリングにより形成した。この後、ａ－Ｓｉユニット１０２及びμｃ－Ｓｉユニット１０４のパターンニング位置から５０μｍ横の位置にＹＡＧレーザを照射し、第１裏面電極層１６、第２裏面電極層１８を短冊状にパターニングした。ＹＡＧレーザは、エネルギー密度０．７Ｊ／ｃｍ３、パルス周波数４ｋＨｚのものを用いた。
　このように形成した光電変換装置を第１のｉ型層４２ａのそれぞれの膜厚について実施例１～４とした。
（比較例１～３）
　上記実施例１～４と同様の形成条件において、第１のｉ型層４２ａを形成せず、膜厚２μｍの第２のｉ型層４２ｂをｐ型層４０上に直接形成した光電変換装置を比較例１とした。
　また、上記実施例１～４と同様の形成条件において、第１のｉ型層４２ａの膜厚を１０ｎｍとし、第２のｉ型層４２ｂの膜厚を１６００ｎｍとした光電変換装置を比較例２とした。更に、上記実施例１～４と同様の形成条件において、第１のｉ型層４２ａの膜厚を４００ｎｍとし、第２のｉ型層４２ｂの膜厚を１６００ｎｍとした光電変換装置を比較例３とした。
（実施例５）
　上記実施例１～４と同様の形成条件において、第１のｉ型層４２ａと第２のｉ型層４２ｂの成膜順を逆にした光電変換装置を実施例５とした。すなわち、第２のｉ型層４２ｂをｐ型層４０上に形成した後、第２のｉ型層４２ｂ上に第１のｉ型層４２ａを形成した。第２のｉ型層４２ｂの膜厚は１．９μｍとし、第１のｉ型層４２ａの膜厚は０．１μｍとした。
（実施例６及び７）
　上記実施例２と同様の形成条件において、第１のｉ型層４２ａを形成する際の原料ガスに含まれるメタン（ＣＨ４）／シラン（ＳｉＨ４）比を変化させ、第１のｉ型層４２ａに含有される炭素の濃度が１×１０２１／ｃｍ３及び３×１０２１／ｃｍ３となるように形成した光電変換装置をそれぞれ実施例６及び７とした。
（比較例４～６）
　上記実施例２と同様の形成条件において、第１のｉ型層４２ａを形成する際の原料ガスに含まれるメタン（ＣＨ４）／シラン（ＳｉＨ４）比を変化させ、第１のｉ型層４２ａに含有される炭素の濃度が８×１０１７／ｃｍ３，６×１０２０／ｃｍ３及び５×１０２１／ｃｍ３となるように形成した光電変換装置をそれぞれ比較例４～６とした。
　表３に、実施例１～４並びに比較例１～３の光電変換装置の開放電圧Ｖｏｃ、短絡電流密度Ｊｓｃ、フィルファクタＦＦ及び効率ηを示す。比較例１の開放電圧Ｖｏｃ、短絡電流密度Ｊｓｃ、フィルファクタＦＦ及び効率ηの平均値をそれぞれ１として実施例１～４の測定値を規格化して示している。
Figure JPOXMLDOC01-appb-T000003
　実施例１では、開放電圧Ｖｏｃは増加しなかったが、短絡電流密度Ｊｓｃが増加し、変換効率ηは２．５％向上した。実施例２～４では開放電圧Ｖｏｃ及び短絡電流密度Ｊｓｃが増加し、変換効率ηはそれぞれ４．０％，３．７％及び２．４％向上した。実施例１～４では、開放電圧Ｖｏｃ及び短絡電流密度Ｊｓｃの増加分に対して、フィルファクタＦＦの低下分は小さく、変換効率ηが向上した。これに対して、第１のｉ型層４２ａを１０ｎｍとした比較例２では、ほとんどのパラメータに変化はなく、第１のｉ型層４２ａがないときとほとんど変化はなかった。また、第１のｉ型層４２ａを４００ｎｍとした比較例３では、フィルファクタＦＦの低下分が大きくなり、変換効率ηが比較例１より小さくなった。なお、実施例５では、比較例１に対して短絡電流密度Ｊｓｃが２％増加した。
　また、表４に示すように、実施例６及び７のように第１のｉ型層４２ａの炭素濃度を１×１０２１／ｃｍ３又は３×１０２１／ｃｍ３とした場合、開放電圧Ｖｏｃ及び短絡電流密度Ｊｓｃが増加し、変換効率ηもそれぞれ４．０％及び３．６％向上した。これに対して、比較例４～６のように、第１のｉ型層４２ａの炭素濃度を８×１０１７／ｃｍ３，６×１０２０／ｃｍ３及び５×１０２１／ｃｍ３とした場合、変換効率ηは小さい値に留まった。
Figure JPOXMLDOC01-appb-T000004
　以上のように、本実施の形態のようにμｃ－Ｓｉユニット１０４のｉ型層４２に比較的膜厚の大きい微結晶炭化シリコン層である第１のｉ型層４２ａを設けることによって開放電圧Ｖｏｃ又は短絡電流密度Ｊｓｃを増加させつつ、フィルファクタＦＦの低下を抑えることができ、光電変換装置１００の光電変換効率ηを向上させることができる。
　なお、本実施の形態では、アモルファスシリコン光電変換ユニット１０２と微結晶シリコン光電変換ユニット１０４とのタンデム構造を例に説明したが、これに限定されるものではなく、微結晶シリコン光電変換ユニット１０４のシングル構造でもよいし、アモルファスシリコン光電変換ユニット１０２以外の光電変換ユニットとの積層構造や３つ以上の光電変換ユニットの積層構造としてもよい。
　１０　透明絶縁基板、１２　透明導電膜、１４　中間層、１６　第1裏面電極層、１８　第２裏面電極層、２０　充填材、２２　保護膜、４０　ｐ型層　４２　ｉ型層　４２ａ　第１のｉ型層、４２ｂ　第２のｉ型層、４４　ｎ型層、１００　光電変換装置。

Claims (6)

  1. 　ｐ型ドーパントを含むｐ型層、発電層となる微結晶シリコン層を含むｉ型層及びｎ型ドーパントを含むｎ型層の積層構造を備えた光電変換装置であって、
    　前記ｉ型層は、前記ｐ型層と前記ｎ型層との間に設けられ、５０ｎｍ以上３００ｎｍ以下の膜厚を有する微結晶炭化シリコン層を備えることを特徴とする光電変換装置。
  2. 　請求項１に記載の光電変換装置であって、
    　前記微結晶炭化シリコン層は、前記ｐ型層と前記微結晶シリコン層との間に配置されることを特徴とする光電変換装置。
  3. 　請求項２に記載の光電変換装置であって、
    　前記微結晶炭化シリコン層は、前記微結晶シリコン層と前記ｎ型層との間に配置されることを特徴とする光電変換装置。
  4. 　請求項１～３のいずれか１つに記載の光電変換装置であって、
    　前記微結晶炭化シリコン層は、炭素を１×１０２１／ｃｍ３以上３×１０２１／ｃｍ３以下の濃度で含むことを特徴とする光電変換装置。
  5. 　ｐ型ドーパントを含むｐ型層、発電層となる微結晶シリコン層を含むｉ型層及びｎ型ドーパントを含むｎ型層の積層構造を備えた光電変換装置の製造方法であって、
    　前記ｐ型層と前記ｎ型層との間に、５０ｎｍ以上３００ｎｍ以下の膜厚を有する微結晶炭化シリコン層を形成することを特徴とする光電変換装置の製造方法。
  6. 　請求項５に記載の光電変換装置の製造方法であって、
    　前記微結晶炭化シリコン層は、シランに対してメタンを１／１０以上１／６以下の割合で供給して形成することを特徴とする光電変換装置の製造方法。
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JPH02218175A (ja) * 1989-02-17 1990-08-30 Sanyo Electric Co Ltd 光起電力素子
JPH04266066A (ja) * 1991-02-20 1992-09-22 Canon Inc 光起電力素子
JP2002016271A (ja) * 2000-06-29 2002-01-18 Fuji Electric Co Ltd 薄膜光電変換素子

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JPH02218175A (ja) * 1989-02-17 1990-08-30 Sanyo Electric Co Ltd 光起電力素子
JPH04266066A (ja) * 1991-02-20 1992-09-22 Canon Inc 光起電力素子
JP2002016271A (ja) * 2000-06-29 2002-01-18 Fuji Electric Co Ltd 薄膜光電変換素子

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