JP3455364B2 - Thin film solar cell and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a unit solar cell composed of a photoelectric conversion layer formed on one surface of a substrate and electrode layers sandwiching the photoelectric conversion layer, connected using a connection electrode layer formed on the other surface of the substrate. Thin film solar cell and manufacturing method thereof.

2. Description of the Related Art Solar cells have been attracting attention as clean energy, and their technological progress has been remarkable. In particular, a photoelectric conversion layer containing amorphous silicon as a main material is easy to form a large area and is inexpensive, and therefore, a thin-film solar cell using the photoelectric conversion layer has great expectations.
Glass substrates have been used for conventional thin film solar cells, but they have the drawbacks of being thick and heavy and fragile, and they are thin and lightweight to improve workability when applied to outdoor roofs. Is becoming more and more demanding. In response to these demands, a flexible thin film solar cell using a flexible plastic film or a foil metal film as a substrate is being put into practical use. A thin-film solar cell is formed by providing a photoelectric conversion layer on one surface of a substrate with electrode layers on both surfaces. Among the electrode layers, the one existing on the light incident side is a transparent electrode layer made of a transparent conductive material such as indium tin oxide (ITO) or zinc oxide (ZnO). Since this transparent electrode layer has a large sheet resistance, electric power is increased due to current flowing through the transparent electrode layer. Therefore, conventionally,
Divide the thin film solar cell into multiple narrow unit cells,
It has a series connection structure in which the divided unit cells are electrically connected to adjacent unit cells. On the other hand, in the thin film solar cell known in Japanese Patent Laid-Open No. 6-342924, a through hole is formed in the insulating substrate, and the transparent electrode layer on the opposite side of the photoelectric conversion layer is provided on the back surface of the substrate by utilizing this through hole. By connecting to the connection electrode layer, the distance of the current path flowing through the transparent electrode layer having a high sheet resistance can be shortened. FIG. 7 conceptually shows a cross-sectional structural view of such a thin film solar cell. After the first through hole 2 is opened in the film substrate 1, the first electrode layer 4 made of, for example, a metal film is formed. Then, after the second through hole 3 is opened, a thin film semiconductor layer 6 such as amorphous silicon to be a photoelectric conversion layer and a second electrode layer 5 of a transparent conductive film such as ITO.
Are stacked. Both layers cover the inner surface of the second through hole 3 and reach the lower end of the second through hole 3. Then, the back side is covered with the connecting third electrode layer 7. The third electrode layer 7 is connected to the first electrode layer 4 on the surface of the substrate 1 via the first electrode layer 4 on the inner surface of the first through hole 2 and the third electrode layer 7. Further, the inner surface of the through hole 3 is connected to the second electrode layer 6 on the substrate surface via the second electrode layer 5 and the third electrode layer 7 which are substantially insulated from the first electrode layer 4 by the semiconductor layer 6. To be done. With such a structure, the first electrode layer 4, the semiconductor layer 6, and the second electrode layer 5 on the front surface of the substrate are arbitrarily divided into a plurality of unit solar cells, and further the third electrode layer 7 on the back surface is provided with the slits 8, 9
By dividing by a dividing line having a different pattern from the dividing line on the surface such as, a series connection structure of unit solar cells is completed. In this case, the first through holes 2 are useful for collecting current of the unit solar cells, and the through holes 3 are useful for the series structure in each unit solar cell. In particular, the third electrode layer 7 may be a composite layer including a third electrode inner layer 71 for reflecting incident light and a third electrode outer layer 72 for lowering the reflectance with respect to laser light when the slit 8 is formed. It is being appreciated. If a material with low reflectance is used, the laser light output can be reduced when processing the slits 8,
It is possible to prevent damage on the front surface side of the substrate. The combination of the third electrode layer includes a third electrode inner layer 71 and a third electrode outer layer 72.
Is known to be a combination of silver (Ag) and chromium (Cr).

However, in the combination of silver (Ag) and chromium (Cr), the thicker the Cr, the better the fill factor (FF) which is a characteristic of the solar cell.
When the thickness is 4 μm or more, there is a problem that Cr peels off. If their thickness is not less than 0.4 μm, the resistance through the first and second through holes 8 and 9 would not be sufficiently low. In addition, since the thickness of 0.4 μm or more is required, peeling of the photoelectric conversion layer side is likely to occur due to the stress of the film and the yield is low. As one of the countermeasures, the inventor has proposed a combination of Ag and copper (Cu) for the third electrode inner layer 71 and the third electrode outer layer 72 (Japanese Patent Application No. 7-129891).
issue). With this combination, there is no peeling of the third metal layer,
Further, a solar cell having a large fill factor (FF), which is one of solar cell characteristics, was obtained. However, both sides of a thin film solar cell having a series connection structure using a combination of silver (Ag) as the inner layer of the third electrode and Cu as the outer layer 72 of the low-reflectance third electrode are coated with a transparent resin, ethylene vinyl acetate copolymer (EVA). )
The thin film solar cell panel is manufactured by closely sealing with, and one of the reliability test items is high temperature and high humidity (85 ° C, 95% R).
H) left for a long time, the first and second through holes 2,
3, the semiconductor layer 6 that wraps around to the third electrode layer 7 side and the second electrode layer 5 that wraps around from the second through hole 3 react with Cu of the third electrode outer layer 72 to form a part of the Cu surface. Discoloration was seen. Further, the characteristics of the solar cell were also deteriorated. Although it is sealed with EVA, it is impossible to completely prevent the invasion of water because EVA itself is a resin.
It is considered that in the portion where Cu and Cu are in direct contact with each other, a chemical reaction of the battery occurs due to the presence of invading water vapor and the standard reduction potential of Ag is higher than that of Cu, so that Cu is eluted. Further, aluminum (Al) can be used as the third electrode inner layer 71. In that case, Al
Since the standard reduction potential of Cu is lower than that of Cu, elution of Cu does not occur. However, again, the reaction with the semiconductor layer 6 that wraps around the second through hole 3 occurred, and discoloration was observed on the surface of the third electrode outer layer 72. Further, when a composite layer of Ag / ITO is used as the third electrode inner layer 71, Cu does not elute, but reacts with the ITO and the semiconductor layer 5 sneaking from the through holes 2 and 3, The surface of Cu of the three-electrode outer layer 72 may be discolored and the solar cell characteristics may be deteriorated. In order to solve the problems of surface discoloration of Cu used as the third electrode outer layer 72 and deterioration of solar cell characteristics, the inventor previously described in Japanese Patent Application No. 7-305527, a third electrode outer layer made of Cu or an alloy thereof. It was proposed to insert a conductive intermediate layer between 72 and the third electrode inner layer 71. FIG. 8 shows a cross section of the thin film solar cell. The conductive intermediate layer 7 is provided between the third electrode outer layer 72 and the third electrode inner layer 71.
3 is inserted. The third electrode inner layer 71 is Ag, the third electrode outer layer 72 is copper, and the intermediate layer 73 is Ti. In the thin film solar cell in which the intermediate layer 73 is inserted as shown in FIG.
It has been shown in the above application that the surface discoloration and the deterioration of solar cell characteristics can be prevented. However, the reliability is certainly improved by including the intermediate layer 73, but as a method for manufacturing a thin film solar cell, a step for forming the intermediate layer must be added, and a film forming apparatus for that is required. become. For example, when a stepping roll type film forming apparatus is used, if the third electrode layer 7 has a three-layer structure, three reaction chambers are required for that, which leads to an increase in product cost. In view of the above problems, an object of the present invention is to provide a thin-film solar cell that can withstand high temperature and high humidity tests, has high long-term reliability, and is easy to manufacture, and a manufacturing method thereof.

In order to solve the above problems, the present invention provides a photoelectric conversion layer having a first electrode layer on the substrate side and a transparent second electrode layer on the opposite side on one surface of an insulating substrate. An amorphous semiconductor layer is laminated, and an inner layer and an outer layer are formed on the other side of the substrate.
Third electrode layer is provided comprising a first electrode layer, the laminate consisting of the photoelectric conversion layer and the second electrode layer and third electrode layer is divided by the slits, respectively, a third one region of the third electrode layer The electrode inner layer is connected to the first electrode layer in one region of the laminated body divided through the first through hole opened in the substrate,
The third electrode outer layer in another region of the third electrode layer is adjacent to the laminate region through a second through hole formed in the substrate, the first electrode layer and the photoelectric conversion layer, and the second electrode layer in the laminate region. in the thin-film solar cell to be connected to, the first through hole
Of the semiconductor layer and the second through hole deposited on the inner surface
The third electrode in contact with the second electrode layer formed inside
The outer layer is made of nickel (Ni) or its alloy. In particular, the third electrode inner layer is preferably made of aluminum (Al) or its alloy. With such a combination, a battery chemical reaction does not occur between the third electrode inner layer and the third electrode outer layer, and the third electrode outer layer does not elute or discolor. The thickness of the third electrode inner layer is preferably in the range of 0.2 to 0.5 μm. The specific resistance of Al is 1.7 times that of conventionally used silver (Ag), and 0.2 μm of Al corresponds to 0.1 μm of Ag. To reduce the loss due to resistance in the third electrode layer,
The thickness of Al or its alloy is preferably thicker, but if the thickness is within such a range, the solar cell characteristics are also improved. Then, from the viewpoint of suppressing the difference in the coefficient of thermal expansion from the substrate or the stress due to heat during film formation, the thickness is 0.5 μm or less. But,
Since the elastic modulus is about ⅓ of Cr, the internal stress does not become too large even if it is 0.4 μm or more, and peeling of the photoelectric conversion layer does not occur. Further, the thickness of the third electrode outer layer is preferably in the range of 0.05 to 0.5 μm. With such a layer thickness range, the YAG laser used for laser processing of Ni has a reflectance of 60% with respect to laser light having a wavelength of 0.53 μm, which is slightly higher than 40% of chromium (Cr), but of Ag. It is lower than 94% and about 72% of Al, the laser output for patterning the third electrode layer can be lowered, and processing is performed without damaging each layer on the photoelectric conversion layer side. In order to reduce the loss due to resistance, it is preferable that the thickness be thick, but if the layer thickness is within such a range, the solar cell characteristics will be improved. From the viewpoint of suppressing the difference in coefficient of thermal expansion from the substrate or the stress due to heat during film formation,
5 μm or less. However, since the elastic modulus is about ½ of Cr, peeling or the like does not occur even if it is 0.4 μm or more. As a method for manufacturing a thin film solar cell according to the present invention,
Step of opening the first through-hole in the insulating substrate, a first electrode layer formed on one surface of the substrate, the first on the other surface of the substrate
Third electrode inner layer connected to the first electrode layer through a through hole
A step of forming a film , the substrate, the first electrode layer, and
A step of forming a second through hole in the third electrode inner layer , a step of forming a semiconductor layer that is a photoelectric conversion layer on the first electrode layer ,
Thin film solar cell comprising a step of forming a transparent second electrode layer on the semiconductor layer except the first through hole portion, and a step of forming a third electrode outer layer on the third electrode inner layer In the manufacturing method of 1., the third electrode outer layer is formed of nickel or its alloy at a substrate temperature of 100 to 250 ° C. By doing so, a third electrode layer is formed in which the third electrode inner layer is covered with the third electrode outer layer of Ni or its alloy. When the substrate temperature is higher than 250 ° C,
Impurities in the semiconductor layer diffuse to cause deterioration of the initial characteristics, and when the substrate temperature is lower than 100 ° C., the fill factor (FF) of the solar cell characteristics shows a slight decreasing tendency. You can avoid those problems in the temperature range of.

BEST MODE FOR CARRYING OUT THE INVENTION As an insulating substrate, aramid, polyether sulfone (PES), polyethylene naphthalate (PEN), polyethylene terephthalate (PE) is used.
T), a plastic film such as polyimide is used. The first electrode layer and the third electrode inner layer (electrode layers for serial connection) on both sides of the substrate are usually formed of the same material by a sputtering method to form a single layer film of silver (Ag), aluminum (Al), or the like. A multilayer film such as Ag / transparent conductive film is used. The intermediate layer is made of titanium (Ti), chromium (Cr), nickel (N).
i), one of molybdenum (Mo), Al, and tantalum (Ta), or an alloy mainly containing one of them.
For example, an aluminum-silicon (Al-Si) alloy or the like is used. An embodiment of the present invention will be described below with reference to the drawings in which the same parts as those in FIGS. [Example] FIG. 1 is a partial cross-sectional view of a thin-film solar cell according to an example of the present invention. On the insulating substrate 1, a thin film semiconductor layer 6 of amorphous silicon, which serves as a photoelectric conversion layer having a second electrode layer 5 and a first electrode layer 4 above and below, is formed. The second electrode layer 5 is a transparent conductive film of ITO, and the first electrode layer 4 is silver. A third electrode inner layer 71 and a third electrode layer 72 are formed on the lower surface of the insulating substrate 1. Third electrode inner layer 7 in contact with the insulating substrate 1
1 is Al, and the third electrode outer layer 72 is Ni. First and second through holes 2 and 3 are opened in the insulating substrate 1, and inside the first through hole 2, the first electrode layer 4, the third electrode inner layer 71,
The semiconductor layer 6 and the third electrode outer layer 72 are laminated. Since the first electrode layer 4 and the third electrode inner layer 71 are directly laminated, the potential of the first electrode layer 4 on the insulating substrate 1 is taken out to the third electrode outer layer 72 on the lower surface of the insulating substrate 1. There is. Inside the second through hole 3, the semiconductor layer 6, the second electrode layer 5, and the third electrode outer layer 72 are laminated. Since the second electrode layer 5 and the third electrode outer layer 72 are directly laminated, the semiconductor layer 6
Potential is taken out to the third electrode outer layer 72 on the lower surface of the insulating substrate 1. That is, the first electrode layer 4 is also the second electrode layer 5
Can also be taken out as the third electrode layer 7 on the lower surface of the substrate 1. Therefore, a slit 9 is provided in the first electrode layer 4, the semiconductor layer 5, and the second electrode layer 6 on the front surface of the substrate 1, and a pattern different from the slit 9 on the front surface is formed on the third electrode inner layer and outer layers 71, 72 on the back surface of the substrate 1. The slit 8 is provided and divided into a plurality of unit solar cells, and a thin film solar cell having a structure in which the unit solar cells are connected in series is configured. The third electrode layer 7 is composed of two layers, that is, the third electrode inner layer 72 and the third electrode layer 72. The third electrode inner layer 71 is for reflecting the incident light, and the reflectance for the laser beam when the slit 8 is formed. The third electrode outer layer 72 for the purpose of lowering If a material with low reflectance is used, the laser light output can be reduced when processing the slits 8,
It is possible to prevent damage on the front surface side of the substrate. FIGS. 2A to 2C and FIGS. 3A to 3E are cross-sectional views for each main manufacturing step shown in the order of main manufacturing steps of the thin film solar cell shown in FIG. FIG. 2A is a sectional view of the substrate 1. As the material of the substrate 1, aramid having a film thickness of 50 μm was used in this embodiment. An insulating plastic film such as PES, PEN, PET, or polyimide can also be used.
Further, the film thickness used in the embodiment is 50 μm, but is not limited to this thickness. A first through hole 2 having a diameter of 1 mm is formed in the substrate 1 by laser processing [(b) of the same figure]. The shape of the hole in this case does not necessarily have to be a circle, but rather the area of the first through hole 2 is as small as possible and the peripheral length is as long as possible in order to improve the characteristics of the solar cell. Good shape. The first electrode layer 4 is formed on the surface of the substrate 1, and the metal to be the third electrode inner layer 71 is formed on the surface opposite to the first electrode layer 4 by the sputtering method [FIG. At this time, the metal to be sputter-deposited is also deposited on the inner surface of the first through hole 2, and is connected to the first electrode layer 4 on the upper surface and the third electrode inner layer 71 on the opposite side. As a material,
Al was used. In addition, a multilayer structure film such as silver (Ag) or Ag / transparent conductive layer can be used. It does not matter which of the first electrode layer 4 and the third electrode inner layer 71 is first,
Preferably, the first electrode layer 4 is formed first. Then, the second through hole 3 having a diameter of 1 mm is formed by laser processing [FIG. 3 (a)]. In this case as well, the shape of the hole does not necessarily have to be circular, and the area of the second through hole 3 is as small as possible, and the peripheral length is as long as possible. is there. Next, the semiconductor layer 6 to be the photoelectric conversion layer is formed [(b) of the same figure]. In this embodiment, a hydrogenated amorphous silicon (a-Si: H) -based material deposited by an ordinary glow discharge decomposition method is used to form n-
An ip junction was formed. At this time, the semiconductor layer 6 is also deposited on the inner surfaces of the first through hole 2 and the second through hole 3. A transparent electrode layer which is the second electrode layer 5 is formed thereon [FIG. In this embodiment, an example of ITO by the sputtering method is shown. An oxide conductive film such as ZnO can also be used. At the time of forming the ITO, a part of the first through hole 2 is covered with a mask so that the ITO is not formed on that part. Then, the third electrode inner layer 71 on the back surface of the substrate 1
Ni is sputter-deposited thereon as the third electrode outer layer 72 [(d) in the figure]. At this time, as the sputtering condition of Ni of the third electrode outer layer 72, it is desirable that the substrate temperature is 250 ° C. or less. If formed at a higher temperature,
The semiconductor layer 6 may be damaged and the characteristics may deteriorate. When Ni was sputtered at 250 ° C. or lower, these phenomena were not observed and stable characteristics were exhibited. Furthermore, when Ni was formed at a temperature lower than 100 ° C., the fill factor (FF) of the solar cell characteristics tended to be slightly lowered.
Therefore, it is most preferable to form within the range of 100 to 250 ° C. Finally, the third electrode layer 7 is formed by the YAG laser.
Then, slits 8 and 9 having a predetermined pattern are formed on the laminated body of the first electrode layer 4, the semiconductor layer 6 and the second electrode layer 5, respectively, and divided to form a serial structure [FIG. (E)]. In this example, Al was used for the third electrode inner layer 71, and it was found that the thickness of Al at that time affects the characteristics of the solar cell. FIG. 4 shows the Al thickness dependence of the fill factor (FF) of the thin film solar cell. The horizontal axis represents Al thickness, and the vertical axis represents FF.
For comparison, the thickness dependence of Ag is also shown. In either case, the third electrode outer layer 72 was Ni having a thickness of 0.2 μm. It can be seen from the figure that Al of the third electrode inner layer 71 needs to have a film thickness of 0.2 μm or more, and preferably has a film thickness of 0.3 μm or more. However, if it is too thick, it may cause peeling or the like, so 0.5 μm or less is desirable. It was also found that the Ni thickness of the third electrode outer layer 72 affects the characteristics of the solar cell. Figure 5 shows the fill factor (F
The dependence of F) on the Ni thickness is shown. The horizontal axis represents Ni thickness, and the vertical axis represents FF. For comparison, the thickness dependence of Cr is also shown. In any case, the third electrode inner layer 71 has a thickness of 0.4.
The Al was set to μm. Conventionally used Cr is 0.4μ
While it is necessary to use m or more, when Ni is used, it is clear that the thickness is 0.05 μm or more, preferably 0.2 μm or more. Also in this case, if the thickness is too thick, the stress increases, so the range of 0.05 to 0.5 μm is preferable. Such a thickness is sufficient also in terms of resistance through the through hole of the substrate and laser separation processing. In particular, 0.1-0.2
When the thickness is μm, the solar cell has a sufficient function as a characteristic, so that the thickness can be considerably reduced. As a result, peeling due to stress or the like is reduced, and the yield can be improved. It was also found that an interface layer such as ZnO that supplements the adhesive force may be provided at the interface between the substrate 1 and the third electrode inner layer 71. In the embodiments described above, the reflectance at the laser wavelength (0.53 μm) used when forming the series connection is as low as about 55%, and when the slits 8 and 9 are processed, the surface opposite to the processed surface is processed. Good processing was possible without damage. Furthermore, after sealing the thin film solar cell of this series connection structure with EVA resin,
A standing test was performed in a high temperature and high humidity atmosphere of 95% RH.
FIG. 6 shows changes in the efficiency of the solar cell in the high temperature and high humidity test. The horizontal axis is time, and the vertical axis is the relative value of efficiency with the initial value being 1. For comparison, a conventional thin film solar cell in which an intermediate layer was formed between the inner layer and the outer layer of the third electrode was also tested at the same time. The thin-film solar cell of this example is the same as the conventional example,
It shows stable characteristics up to about 2000 hours. That is, the thin film solar cell of the present embodiment using Al for the third electrode inner layer 71 for collecting current and Ni for the third electrode outer layer 72 for the low reflectance film at the time of laser processing is the third electrode inner layer 71. And the third electrode outer layer 72, and the third electrode outer layer 72 and the second electrode layer 5 or the semiconductor layer 6 do not cause a battery chemical reaction, an alloy reaction, or a reaction due to contact, so that the reliability is high. Therefore, it is not necessary to interpose an intermediate layer between the third electrode inner layer 71 and the third electrode outer layer 72. For example, when a stepping roll type film forming apparatus is used, only two vacuum chambers are required, which reduces the cost of the apparatus. Also, the cost can be reduced. The fact that Ag is not used can be said to be a structure suitable for cost reduction of the thin film solar cell. Further, since the third electrode outer layer 72 may be a thin layer, the problem of peeling due to being too thick does not occur unlike the conventionally used Cr. Third electrode inner layer 71
Is not limited to pure Al, but similar effects can be obtained with an Al alloy containing Si, for example.
It was found that the same effect can be obtained not only with pure Ni but also with a Ni alloy containing, for example, Ti, Ta, Cr, Mo. When Ni is used for the third electrode outer layer 72, Ag can be used as the third electrode inner layer 71 by inserting an intermediate layer.

As described above, N is formed on the outer layer of the third electrode.
The thin film solar cell of the present invention using i or its alloy is
Even if an intermediate layer or the like is not interposed between the inner layer and the outer layer of the third electrode, a battery chemical reaction, an alloy reaction or the like with both layers or the second electrode layer or the semiconductor layer does not occur. As a result, a highly reliable thin film solar cell can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a thin film solar cell according to an embodiment of the present invention.

2A to 2C are cross-sectional views sequentially showing the first half of the manufacturing process of the thin-film solar cell of FIG.

3 (a) to 3 (e) are cross-sectional views sequentially showing a manufacturing process of the thin film solar cell following FIG. 2 (c).

FIG. 4 is a diagram showing the relationship between the material and film thickness of the third electrode inner layer and the fill factor of the solar cell.

FIG. 5 is a diagram showing the relationship between the material and film thickness of the third electrode outer layer and the fill factor of the solar cell.

FIG. 6 is a graph showing deterioration curves of efficiency of a thin film solar cell of one example of the present invention and a thin film solar cell of a comparative example in a high temperature and high humidity storage test.

FIG. 7 is a partial cross-sectional view of a conventional thin film solar cell.

FIG. 8 is a partial cross-sectional view of another conventional thin-film solar cell.

[Explanation of symbols]

1 Insulating substrate 2 First through hole 3 Second through hole 4 First electrode layer 5 Second electrode layer 6 semiconductor layers 7 Third electrode layer 71 Third electrode inner layer 72 Third electrode outer layer 73 Middle class 8 slits 9 slits

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-7-321355 (JP, A) JP-A-7-307481 (JP, A) JP-A-59-220979 (JP, A) JP-A-2- 167890 (JP, A) Tokuyo Hyohei 4-504033 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 31/04-31/078

Claims (5)

(57) [Claims] 1. An amorphous semiconductor layer, which is a photoelectric conversion layer in which a first electrode layer is provided on the substrate side and a transparent second electrode layer is provided on the opposite side, is laminated on one surface of an insulating substrate. Inner layer on the other side
And a third electrode layer comprising an outer layer and a first electrode layer,
The laminate including the photoelectric conversion layer and the second electrode layer and the third electrode layer were each divided by the slit , and the third electrode inner layer in one region of the third electrode layer was divided through the first through hole formed in the substrate. The third electrode outer layer is connected to the first electrode layer in one region of the laminate , and the third electrode outer layer in another region of the third electrode layer is provided through the second through hole formed in the substrate, the first electrode layer and the photoelectric conversion layer. In a thin-film solar cell connected to a second electrode layer in a laminate region adjacent to the laminate region, the semiconductor layer deposited on the inner surface of the first through hole, and
Contact with the second electrode layer formed inside the second through hole
The thin film solar cell, wherein the third electrode outer layer comprises nickel or an alloy thereof. 2. A thin-film solar cell according to claim 1, characterized in that said third electrodes inner layer is made of aluminum or its alloys. Wherein the thickness of the inner layer said third electrodes is 0.2 to 0.5
The thin film solar cell according to claim 2, wherein the thin film solar cell is in the range of μm. 4. A thickness of the third conductive Gokugaiso is 0.05 to 0.
The thin film solar cell according to any one of claims 1 to 3, wherein the thin film solar cell has a thickness of 5 µm. 5. A step of forming a first through hole in an insulating substrate, before.
A first electrode layer formed on one surface of a serial board, the other surface of the substrate
And is connected to the first electrode layer via the first through hole on the top.
Forming a third electrode inner layer, the substrate and the first electrode
A step of forming a second through hole in the layer and the third electrode inner layer,
A semiconductor layer that is a photoelectric conversion layer is formed on the first electrode layer .
The step of forming a transparent second electrode layer on the semiconductor layer except the first through-hole portion, and the step of forming a transparent second electrode layer on the third electrode inner layer.
In the method for manufacturing a thin film solar cell comprising a step of forming a third electrode layer, said third electrode layer, in the range of the substrate temperature of 100 to 250 ° C., and characterized in that the deposition of an alloy of nickel or its Method for manufacturing thin film solar cell.