JP4717122B2 - Method for manufacturing thin film solar cell - Google Patents

Description

  The present invention relates to a method for manufacturing a thin film solar cell having a laminated structure including a plurality of photoelectric conversion layers having different band gaps.

  In recent years, thin-film solar cells have been developed to reduce the cost of solar cells. In particular, thin-film silicon solar cells have been developed vigorously because they have no problems in terms of resources and have little influence on the environment of materials. Generally, since the photoelectric conversion efficiency of a thin film silicon solar cell is lower than the photoelectric conversion efficiency of a polycrystalline silicon solar cell, the improvement of the efficiency of a thin film silicon solar cell has been an issue.

  In order to improve the efficiency of a thin-film silicon solar cell, it is effective to multi-junction two or more types of solar cells in series, and an amorphous silicon (hereinafter abbreviated as a-Si) cell and microcrystalline silicon (hereinafter, A multi-junction thin-film silicon solar cell in which a cell, expressed as μc-Si), an a-Si cell, and amorphous SiGe (hereinafter, expressed as a-SiGe) are connected in series has been developed.

In order to further improve the efficiency of these multi-junction thin-film silicon solar cells, light is transmitted between the first photoelectric conversion layer and the second photoelectric conversion layer formed by being laminated on the light-transmitting insulating substrate. Development of a multi-junction thin-film silicon solar cell having a structure in which an intermediate layer having an effect of increasing the generated current of the first photoelectric conversion layer and increasing the photoelectric conversion efficiency is provided. As this intermediate layer, a transparent conductive film is used. Conventionally, a ZnO-based film has been used, but in recent years, a SiO _x- based transparent conductive film has been used (for example, a patent) References 1 and 2).

The SiO _x film as an intermediate layer used in the thin film solar cell described in Patent Documents 1 and 2 takes the form of a silicon composite phase containing a silicon crystal phase dispersed in an amorphous alloy matrix of silicon and oxygen. . This SiO _x film has an electric conductivity that does not hinder the operation of the solar cell in the film thickness direction, but the electric conductivity in the in-plane direction is extremely small, and an integrated thin film solar cell is modularized. In this case, it is possible to suppress a decrease in efficiency due to a current flowing in the in-plane direction.

Japanese Patent No. 4063735 Japanese Patent No. 4025744

In the method of manufacturing a thin-film solar cell described in Patent Document 1 described above, the SiO _x film as an intermediate layer is formed by a plasma CVD (Chemical Vapor Deposition) method using CO ₂ / SiH ₄ gas. ₂ will contaminate the photoelectric conversion layer. In order to prevent the deterioration of the characteristics of the photoelectric conversion layer due to the CO ₂ contamination, a SiO _x film is formed separately from the plasma CVD apparatus for forming the films constituting the first and second photoelectric conversion layers. Therefore, there is a problem that a plasma CVD apparatus is required separately, and the apparatus cost is increased.

In addition, in the method for manufacturing a thin-film solar cell described in Patent Document 2, an SiO _x film that is an n layer of the first photoelectric conversion layer is formed by a plasma CVD method, and then exposed to the atmosphere, thereby exposing the SiO _x film. Is forming. However, when the SiO _x film is used as the n layer of the first photoelectric conversion layer, the resistance of the n layer is increased as compared with the case where an n layer of a-Si or μc-Si that is normally used is used. For this reason, there is a problem in that the current at the operating point when operated as a solar cell is reduced and the photoelectric conversion efficiency is lowered.

The present invention has been made in view of the above, and a method of manufacturing a thin film solar cell in which a plurality of photoelectric conversion layers having pin junctions are stacked and an intermediate layer made of at least one SiO _x film is inserted between the photoelectric conversion layers The purpose of the present invention is to obtain a method for producing a thin-film solar cell that suppresses the production cost of the thin-film solar cell as compared with the conventional method and does not cause a decrease in photoelectric conversion efficiency of the photoelectric conversion layer formed under the intermediate layer. .

  In order to achieve the above object, a method of manufacturing a thin-film solar cell according to the present invention includes a first step of forming a first electrode layer made of a transparent conductive material on a light-transmitting substrate, and the first step. Forming a first photoelectric conversion layer in which a first conductive type semiconductor layer made of a semiconductor material containing silicon, an intrinsic semiconductor layer, and a second conductive type semiconductor layer are sequentially stacked on the electrode layer; A step of forming a composite layer in which microcrystalline silicon and amorphous silicon of the second conductivity type are mixed on the semiconductor layer of the second conductivity type, and a plasma containing oxygen gas in the composite A fourth step of irradiating the layer to form an intermediate layer in which microcrystalline silicon and amorphous silicon oxide are mixed, and silicon having a band gap smaller than that of the first photoelectric conversion layer is included on the intermediate layer 1st made of semiconductor material A fifth step of forming a second photoelectric conversion layer in which a conductive semiconductor layer, an intrinsic semiconductor layer, and a second conductive type semiconductor layer are sequentially stacked; and a conductive material on the second photoelectric conversion layer And a sixth step of forming a second electrode layer.

According to the present invention, in the method for manufacturing a thin-film solar cell in which a plurality of photoelectric conversion layers and one or more intermediate layers are stacked, the intermediate layer provided to improve the photoelectric conversion efficiency is provided on the first photoelectric conversion layer. After the formation of the second semiconductor layer, a composite film containing microcrystalline silicon and amorphous silicon is continuously formed. Thereafter, an intermediate layer made of silicon and silicon oxide is formed by irradiation with plasma containing oxygen in the atmosphere. Since the oxygen plasma irradiation treatment is performed in the atmosphere, the manufacturing cost can be reduced as compared with the case where the intermediate layer is formed with a dedicated plasma CVD apparatus for forming the intermediate layer, and the first There is no possibility that the photoelectric conversion layer is contaminated by CO ₂ . In addition, since the semiconductor layer of the second conductivity type of the first photoelectric conversion layer uses a semiconductor such as an n-layer of a-Si or μc-Si, the photoelectric conversion efficiency of the manufactured thin film solar cell is As compared with the case where silicon oxide is used for the conductive type semiconductor layer, the effect can be improved.

  Embodiments of a method for manufacturing a thin-film solar cell according to the present invention will be described below in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments. Moreover, the cross-sectional views of the thin film solar cell used in the following embodiments are schematic, and the relationship between the thickness and width of the layers, the ratio of the thicknesses of the layers, and the like are different from the actual ones.

  Initially, the outline | summary of a structure of the thin film solar cell manufactured by this embodiment is demonstrated. FIG. 1 is a partial cross-sectional view schematically showing an example of the configuration of a general thin film solar cell. In the thin-film solar cell 1, a surface electrode layer 11, a first photoelectric conversion layer 13, an intermediate layer 14, a second photoelectric conversion layer 15, and a back electrode layer 16 are sequentially stacked on an insulating translucent substrate 2. It is formed by a photoelectric conversion element. The first photoelectric conversion layer 13 and the second photoelectric conversion layer 15 are connected in series via the intermediate layer 14. In this thin-film solar cell 1, the surface on the light incident side, in this example, the surface on the insulating translucent substrate 2 side is called the surface, and the surface opposite to the surface, in this example, the side on which the back electrode layer 16 is formed. Is called the back side.

The insulating light-transmitting substrate 2 is made of a light-transmitting organic film material such as a glass substrate with high light transmittance or polyimide. The surface electrode layer 11 is made of SnO ₂ , ZnO doped with Al, Ga or B, or a transparent conductive oxide material such as a laminated film thereof.

  The first photoelectric conversion layer 13 is configured by a semiconductor layer having a pin structure in which a p-type semiconductor layer 131, an i-type semiconductor layer 132, and an n-type semiconductor layer 133 are sequentially stacked. Further, the second photoelectric conversion layer 15 has a pin structure in which a p-type semiconductor layer 151, an i-type semiconductor layer 152, and an n-type semiconductor layer 153 are sequentially stacked, and has a band gap that is larger than that of the first photoelectric conversion layer 13. Of a narrow semiconductor layer.

  Here, for the first and second photoelectric conversion layers 13 and 15, a semiconductor material containing silicon such as a-Si, μc-Si, or a-SiGe, or a mixture of these semiconductor materials can be used. . However, it is necessary to select and laminate the semiconductor material used so that the band gap is narrowed as the semiconductor material is laminated from the insulating translucent substrate 2 side. Here, the i-type semiconductor layer 132 of the first photoelectric conversion layer 13 is formed of a-Si, and the i-type semiconductor layer 152 of the second photoelectric conversion layer 15 is formed of μc-Si.

  The intermediate layer 14 is a film made of n-type microcrystalline silicon (μc-Si) and amorphous silicon oxide. The intermediate layer 14 reflects a part of the light incident from the first photoelectric conversion layer 13 side to the first photoelectric conversion layer 13 side and the remaining light to the rear second photoelectric conversion layer 15 side. Make it transparent. More specifically, the intermediate layer 14 is configured to receive light in a wavelength range that can be absorbed by the first photoelectric conversion layer 13 among the light incident from the first photoelectric conversion layer 13 side. It is desirable to have a function of reflecting light in the other wavelength range and transmitting light in other wavelength ranges to the second photoelectric conversion layer 15 side. By providing such an intermediate layer 14, the effective film thickness of the first photoelectric conversion layer 13 can be increased. The intermediate layer 14 has an electric conductivity that does not hinder the operation of the solar cell in the film thickness direction, and has an extremely small electric conductivity in the in-plane direction. In the following, a stacked body including the first photoelectric conversion layer 13, the intermediate layer 14, and the second photoelectric conversion layer 15 is referred to as a photoelectric conversion stacked body 12.

  The back electrode layer 16 is preferably made of a material having high conductivity and high reflectance. Here, a back transparent conductive film 161 such as ZnO doped with Al, Ga, or B formed on the second photoelectric conversion layer 15 and a film in which Al is laminated on Ag, Al, or Ag, or The case where it comprises a laminated film with the back surface conductive film 162 which laminated Ti or TiN on Ag or Al is shown. This is only an example, and the back electrode layer 16 may be composed of only one metal film such as Ag or Al. The back electrode layer 16 collects the photocurrent generated by the photoelectric conversion laminate 12 and reflects light having a wavelength that is difficult to be absorbed by the second photoelectric conversion layer 15 to the second photoelectric conversion layer 15 side. Also have.

  In this example, the case where two photoelectric conversion layers are stacked is described, but the stacked photoelectric conversion layers may be a multilayer of three or more layers. However, in this case, as described above, a semiconductor material whose band gap becomes narrower as it goes upward from the insulating translucent substrate 2 is selected. In this example, each photoelectric conversion layer has a structure in which a p-type semiconductor layer, an i-type semiconductor layer, and an n-type semiconductor layer are sequentially stacked from the insulating light-transmitting substrate 2 side. A structure in which an n-type semiconductor layer, an i-type semiconductor layer, and a p-type semiconductor layer are sequentially stacked from the second side may be used.

  Here, an outline of the operation in the thin film solar cell 1 having such a structure will be described. When sunlight enters from the insulating translucent substrate 2 side (the surface on which the photoelectric conversion laminate 12 is not formed), the i-type semiconductor layers 132 and 152 of the first and second photoelectric conversion layers 13 and 15 Free carriers are generated. The generated free carriers are generated by the built-in electric field formed by the p-type semiconductor layers 131 and 151 and the n-type semiconductor layers 133 and 153 of the first and second photoelectric conversion layers 13 and 15, and the electrons are transferred to the back electrode layer 16 side. The holes are transported to the surface electrode layer 11 side, and current is generated. Then, current is taken out from the terminals connected to the front electrode layer 11 and the back electrode layer 16.

  Below, the manufacturing method of the thin film solar cell 1 which has the above-mentioned structure is demonstrated. FIGS. 2-1 to 2-5 are cross-sectional views schematically showing an example of a method for manufacturing a thin film solar cell according to an embodiment of the present invention. FIG. 3 shows an intermediate layer obtained by subjecting a composite layer to plasma treatment. It is a figure which shows typically the state which forms.

First, as shown in FIG. 2A, a surface electrode layer 11 made of a transparent conductive material is formed on an insulating translucent substrate 2 such as a glass substrate by a film forming method such as a CVD method or a sputtering method. The surface electrode layer 11 is formed of SnO ₂ , ZnO doped with Al, Ga or B, or a laminated film thereof, and has a film thickness of, for example, 0.3 to 2 μm.

Next, as shown in FIG. 2B, the first photoelectric conversion layer 13 is formed on the surface electrode layer 11 by using a plasma CVD method. Specifically, first, for example, SiH ₄ gas, H ₂ gas, and B ₂ H ₆ gas are introduced into the deposition chamber by plasma CVD, and the p-type semiconductor layer 131 is deposited under the condition that an amorphous silicon film is deposited. Is formed on the entire surface of the surface electrode layer 11. Here, the B ₂ H ₆ gas is a source gas for supplying B, which is a dopant material for making the semiconductor layer p-type, into the film. Next, for example, SiH ₄ gas and H ₂ gas are introduced into the deposition chamber by plasma CVD, and an i-type semiconductor layer 132 is formed on the entire surface of the p-type semiconductor layer 131 under the condition that an amorphous silicon film is deposited. To do. At this time, since the i-type semiconductor layer 132 needs to be an intrinsic semiconductor, doping gas is not introduced.

Further, on the i-type semiconductor layer 132, for example, SiH ₄ gas, H ₂ gas, and PH ₃ gas are introduced into the deposition chamber by plasma CVD, and the n-type semiconductor is deposited under the condition that a microcrystalline silicon film is deposited. The layer 133 is formed on the entire surface of the i-type semiconductor layer 132. Here, the PH ₃ gas is a source gas for supplying P, which is a dopant material for making the semiconductor layer n-type, into the film. Thus, the first photoelectric conversion layer 13 is formed. Note that the p-type semiconductor layer 131, the i-type semiconductor layer 132, and the n-type semiconductor layer 133 normally do not contain gas in order to prevent cross-contamination of B ₂ H ₆ gas and PH ₃ gas that are doping gases. The films are continuously formed in different independent film forming chambers (CVD apparatuses).

Next, as shown in FIG. 2C, on the n-type semiconductor layer 133 of the first photoelectric conversion layer 13, a microcrystalline-amorphous silicon composite composed of μc-Si and a-Si, which is the base of the intermediate layer 14. A layer (hereinafter simply referred to as a composite layer) 14 </ b> A is formed in the same deposition chamber as the n-type semiconductor layer 133. The composite layer 14A is formed by introducing, for example, SiH ₄ gas, H ₂ gas, and PH ₃ gas into the film forming chamber, similarly to the first n-type semiconductor layer 133. Since this composite layer 14A needs to be n-type in order to ensure conductivity, PH ₃ gas, which is a raw material gas for supplying P, which is a dopant material, into the film is also introduced.

Since the material gas and the dopant gas for forming the composite layer 14A are the same as those of the n-type semiconductor layer 133 of the first photoelectric conversion layer 13, a film formation chamber (in which the n-type semiconductor layer 133 is formed) Films can be continuously formed in the same film formation chamber (CVD apparatus) as the CVD apparatus. However, the composite layer 14A is more crystalline than the microcrystalline silicon film forming the n-type semiconductor layer 133 in order to ensure good conductivity in the film thickness direction even after being finally oxidized by atmospheric plasma treatment. To increase. Specifically, the scattering of 520 cm ⁻¹ due to μc-Si with respect to the intensity I _a of the scattering peak of 480 cm ⁻¹ due to a-Si in the scattering spectrum by the prepared composite layer 14 </ b> A measured by Raman scattering. The ratio (crystallization rate) I _c / I _a of the peak intensity I _c is set to I _c / I _a > 8, which is higher than I _c / I _a = 5 of the n-type semiconductor layer 133.

This crystallization rate can be changed by changing the input power to the plasma CVD apparatus or changing the ratio of the raw material gas to be introduced. For example, assuming that the input power to the plasma CVD apparatus at the time of forming the n-type semiconductor layer 133 is 200 W, for example, the above crystallization is performed by forming the input power at the time of forming the composite layer 14A at a higher 500 W. A composite layer 14A having _a rate I _c / I _a > 8 can be formed. In addition, when the n-type semiconductor layer 133 is formed, if H ₂ is introduced so that the flow rate ratio H ₂ / SiH ₄ of the source gas is 50 times or less, it is introduced when the composite layer 14A is formed. H ₂ gas, by introducing the H ₂ gas as the raw material gas flow rate ratio H ₂ / SiH ₄ of the 80 times or more, the composite layer 14A having the above-mentioned crystallization rate I _c / I _a> 8 Can be formed.

  Thereafter, as shown in FIG. 2-4, the composite layer 14A is oxidized by plasma treatment in the atmosphere to form an intermediate layer 14 containing n-type microcrystalline silicon and amorphous silicon oxide. FIG. 3 is a diagram schematically showing a state in which the composite layer is subjected to plasma treatment to form an intermediate layer. As shown in this figure, the insulating light-transmitting substrate 2 on which the composite layer 14A is formed has the same width as that of the insulating light-transmitting substrate 2, and a gas 41 containing oxygen is converted into plasma to be insulating light-transmitting. A plasma irradiation nozzle 31 for irradiating the substrate 2 is disposed. As the gas 41 introduced into the plasma irradiation nozzle 31, oxygen, a mixed gas of oxygen and argon, or a mixed gas of oxygen and nitrogen can be used.

  After the plasma irradiation nozzle 31 is arranged above the right end on the insulating translucent substrate 2, the composite layer 14A is irradiated with the plasma 42 containing stripe-like oxygen from the plasma irradiation nozzle 31. Then, the plasma irradiation nozzle 31 or the insulating light-transmitting substrate 2 is linearly moved in the left-right direction on the paper surface so that the plasma 42 is irradiated on the entire surface of the insulating light-transmitting substrate 2 (composite layer 14A). As a result, in the region irradiated with the plasma 42, the composite layer 14A is oxidized. At this time, since the composite layer 14A is in a state in which a-Si and μc-Si are mixed as described above, when the plasma 42 is irradiated, a- is thermodynamically more unstable than μc-Si. Si is oxidized first, and amorphous silicon oxide is formed. As a result, the intermediate layer 14 is made of amorphous silicon oxide and μc-Si. Here, the plasma irradiation nozzle 31 does not need to have the same width as that of the insulating translucent substrate 2, and may be any configuration as long as the entire upper surface of the insulating translucent substrate 2 can be scanned.

  Although the plasma irradiation conditions differ depending on the gas type and gas mixture ratio of the gas 41 to be used, here, a specific example of the case where oxygen gas is supplied as the gas 41 and plasma irradiation is performed will be described. In addition, since the conditions differ depending on the size of the composite layer 14A to be processed, in this example, the film 42 is formed on the entire surface of the insulating translucent substrate 2 having a width of 30 cm and a length of 40 cm. Are scanned to oxidize the composite layer 14A.

  For example, a transparent conductive film (surface electrode layer 11) on the insulating translucent substrate 2, a p-type amorphous silicon film (p-type semiconductor layer 131) of the first photoelectric conversion layer 13, and an i-type amorphous silicon (i-type semiconductor). Layer 132), an n-type microcrystalline silicon film (n-type semiconductor layer 133), and a composite layer 14A (n-type microcrystalline silicon film) are sequentially formed in thicknesses of 1 μm, 15 nm, 300 nm, 10 nm, and 50 nm, respectively. Shall. Further, the flow rate of the oxygen gas used as the material of the plasma 42 is set to 100 NL / min, the high frequency power for converting the oxygen gas into plasma is set to 1 kW, and the moving speed of the insulating translucent substrate 2 is set to 5 mm / sec. By irradiating under this condition, the composite layer 14A is oxidized, and the intermediate layer 14 made of amorphous silicon oxide and microcrystalline silicon is formed. Note that the intermediate layer 14 can be formed from the composite layer 14A having a desired thickness by changing the high-frequency power or the scan speed. For example, when the composite layer 14A is thick, the high frequency power may be increased or the scan speed may be decreased.

In this way, when the composite layer 14A is formed, a film in which an amorphous silicon film and a microcrystalline silicon film are mixed is formed, so that no CO ₂ gas is used. Therefore, the second conductive type semiconductor layer 113 of the first photoelectric conversion layer 13 formed in the same film formation chamber as the composite layer 14A is not contaminated by CO ₂ and the first photoelectric conversion layer is not contaminated. There is no possibility of deteriorating 13.

After forming the intermediate layer 14 as described above, as shown in FIG. 2-5, a semiconductor material having a band gap smaller than that of the first photoelectric conversion layer 13 is formed on the intermediate layer 14 by using a plasma CVD method. A second photoelectric conversion layer 15 made of is formed. Specifically, first, for example, SiH ₄ gas, H ₂ gas, and B ₂ H ₆ gas are introduced into the deposition chamber by plasma CVD, and a p-type semiconductor layer is deposited under the condition that a microcrystalline silicon film is deposited. 151 is formed on the entire surface of the intermediate layer 14. Here, the B ₂ H ₆ gas is a source gas for supplying B, which is a dopant material for making the semiconductor layer p-type, into the film. Next, for example, SiH ₄ gas and H ₂ gas are introduced into the deposition chamber by plasma CVD, and the i-type semiconductor layer 152 is placed on the entire surface of the p-type semiconductor layer 151 under the condition that a microcrystalline silicon film is deposited. Form. At this time, since the i-type semiconductor layer 152 needs to be an intrinsic semiconductor, doping gas is not introduced.

Further, on the i-type semiconductor layer 152, for example, SiH ₄ gas, H ₂ gas, and PH ₃ gas are introduced into the deposition chamber by plasma CVD, and the n-type semiconductor is deposited under the condition that a microcrystalline silicon film is deposited. The layer 153 is formed on the entire surface of the i-type semiconductor layer 152. Here, the PH ₃ gas is a source gas for supplying P, which is a dopant material for making the semiconductor layer n-type, into the film. Thus, the second photoelectric conversion layer 15 is formed. Note that the p-type semiconductor layer 151, the i-type semiconductor layer 152, and the n-type semiconductor layer 153 normally do not contain gas in order to prevent cross-contamination of B ₂ H ₆ gas and PH ₃ gas that are doping gases. The films are continuously formed in different independent film forming chambers (CVD apparatuses).

  Then, the back electrode layer 16 is formed on the n-type semiconductor layer 153 of the second photoelectric conversion layer 15. Specifically, for example, a back transparent conductive film 161 such as ZnO doped with Al, Ga, or B is formed by a film forming method such as sputtering, and then Ag, Al, or a film in which Al is laminated on Ag. Alternatively, the back conductive film 162 in which Ti or TiN is laminated on Ag or Al is formed by a film forming method such as sputtering. As a result, the back electrode layer 16 composed of the back transparent conductive film 161 and the back conductive film 162 is formed. Thus, the thin film solar cell 1 having the structure shown in FIG. 1 is manufactured.

According to this embodiment, after forming the n-type semiconductor layer 133 made of the n-type microcrystalline silicon film of the first photoelectric conversion layer 13, the crystallization rate is higher than that of the n-type semiconductor layer 133 in the same environment. A composite layer 14A in which a high-type n-type microcrystalline silicon film and an n-type amorphous silicon film are mixed is formed without using CO ₂ gas, and plasma treatment is performed on the composite layer 14A by plasma containing oxygen, whereby an amorphous state is obtained. Since the intermediate layer 14 made of silicon oxide and microcrystalline silicon is formed, the underlying n-type microcrystal which is the second conductive type semiconductor layer 133 of the first photoelectric conversion layer 13 when the intermediate layer 14 is formed. The problem that the silicon film is contaminated with CO ₂ can be prevented.

  In order to prevent this contamination, a method of forming the intermediate layer 14 with another plasma CVD apparatus different from the n-type semiconductor layer 133 of the first photoelectric conversion layer 13 can be considered, but an expensive large-sized CVD apparatus is required. However, according to the method shown in this embodiment, since the composite layer 14A can be processed by a relatively simple technique in the atmosphere, the intermediate layer 14 is formed by the CVD method. As compared with the case where the film is formed, the manufacturing cost can be kept low. Furthermore, since a semiconductor such as an n-type μc-Si film is used for the n-type semiconductor layer 133 of the first photoelectric conversion layer 13, the photoelectric conversion efficiency of the manufactured thin-film solar cell 1 is n-type semiconductor layer 133. This also has the effect of improving compared to the case where silicon oxide is used.

  As described above, the method for manufacturing a thin-film solar cell according to the present invention is useful for a multi-junction thin-film solar cell in which a plurality of photoelectric conversion layers are stacked via an intermediate layer.

It is a partial sectional view showing typically an example of composition of a general thin film solar cell. It is sectional drawing which shows typically an example of the manufacturing method of the thin film solar cell by embodiment of this invention (the 1). It is sectional drawing which shows typically an example of the manufacturing method of the thin film solar cell by embodiment of this invention (the 2). It is sectional drawing which shows typically an example of the manufacturing method of the thin film solar cell by embodiment of this invention (the 3). It is sectional drawing which shows typically an example of the manufacturing method of the thin film solar cell by embodiment of this invention (the 4). It is sectional drawing which shows typically an example of the manufacturing method of the thin film solar cell by embodiment of this invention (the 5). It is a figure which shows typically the state which performs a plasma process to a composite layer and forms an intermediate | middle layer.

DESCRIPTION OF SYMBOLS 1 Thin film solar cell 2 Insulating translucent board | substrate 11 Front surface electrode layer 12 Photoelectric conversion laminated body 13 1st photoelectric conversion layer 14 Intermediate | middle layer 14A Composite layer 15 2nd photoelectric conversion layer 16 Back surface electrode layer 31 Plasma irradiation nozzle 41 Gas 42 Plasma 131, 151 p-type semiconductor layer 132, 152 i-type semiconductor layer 133, 153 n-type semiconductor layer 161 Back side transparent conductive film 162 Back side conductive film

Claims (5)

A first step of forming a first electrode layer made of a transparent conductive material on a light-transmitting substrate;
On the first electrode layer, a first photoelectric conversion layer in which a first conductive semiconductor layer made of a semiconductor material containing silicon, an intrinsic semiconductor layer, and a second conductive semiconductor layer are sequentially stacked is formed. A second step;
A third step of forming a composite layer in which microcrystalline silicon and amorphous silicon of the second conductivity type are mixed on the semiconductor layer of the second conductivity type;
A fourth step of irradiating the composite layer with plasma containing oxygen gas in the atmosphere to form an intermediate layer in which microcrystalline silicon and amorphous silicon oxide are mixed;
On the intermediate layer, a first conductive type semiconductor layer, an intrinsic semiconductor layer, and a second conductive type semiconductor layer made of a semiconductor material containing silicon having a smaller band gap than the first photoelectric conversion layer are sequentially stacked. A fifth step of forming the second photoelectric conversion layer,
A sixth step of forming a second electrode layer made of a conductive material on the second photoelectric conversion layer;
The manufacturing method of the thin film solar cell characterized by including. In the second step, the second conductive type semiconductor layer of the first photoelectric conversion layer is formed of a microcrystalline silicon film,
2. The composite layer according to claim 1, wherein in the third step, the composite layer is formed such that the crystallinity of the composite layer is higher than the crystallinity of the second conductivity type semiconductor layer. The manufacturing method of the thin film solar cell of description.   The thin film solar cell according to claim 2, wherein the crystallinity is defined by a ratio of a scattering peak caused by microcrystalline silicon to a scattering peak caused by amorphous silicon contained in the film in Raman scattering. Manufacturing method. The formation of the first conductivity type semiconductor layer, the intrinsic semiconductor layer, and the second conductivity type semiconductor layer in the second step is performed in different film formation chambers by plasma CVD,
The formation of the intermediate layer in the third step is performed in the same film formation chamber as the film formation chamber in which the semiconductor layer of the second conductivity type is formed by a plasma CVD method. The manufacturing method of the thin film solar cell as described in any one of -3.   5. The thin film solar cell according to claim 1, wherein the third to fifth steps are repeatedly performed after the fifth step and before the sixth step. Production method.

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