JPH11330511A - Thin film solar cell and its forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin film solar cell in which a thin film solar cell pattern formation is made by utilizing characteristics of palladium of a hydrogen occulusive metal instead of conventional chemical etching and a laser patterning; and its forming method. SOLUTION: In a thin film solar cell in which a first electrode layer 16, an amorphous silicon layer 20 and a transparent second electrode layer 26 are sequently formed from a base material 1 side on an insulative base material 11, a palladium layer which is pattern-formed by applying heat on the first electrode layer 16 is used. Further, in a method for forming this cell, a-Si:H layer and a transparent electrode layer formed by stacking on the electrode layer composed of palladium are weakened by applying heat on a palladium layer and released to form pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin-film solar cell and a method for forming the same, and more particularly, to using palladium, which is a hydrogen-absorbing metal, as a substrate-side first electrode, and the first electrode made of the palladium stores hydrogen. The present invention relates to a pattern-formed solar cell utilizing the property of becoming brittle as a result, and a method of manufacturing the same.

[0002]

2. Description of the Related Art As a solar cell capable of realizing low cost and mass productivity, SCAF (Series-Connectivity) is known.
n through Appartures form
(edon Film) structure solar cell has been proposed.
This is formed by laminating a metal electrode, an a-Si layer, and a transparent electrode on a film substrate, but it is necessary to pattern each thin film layer after forming the thin film. Conventionally,
This patterning is usually performed by chemical etching by photolithography or laser scribing.

FIG. 11 is a diagram showing a conventional process of forming a thin-film solar cell. In this step, first, as shown in FIG. 11A, a base material 41 such as glass or a plastic film is prepared. Next, in order to form a first electrode on the base material, a metal thin film to be the metal electrode layer 42 is formed by vapor deposition, sputtering, or the like (FIG. 11B). As the metal material, any conductive material may be used, such as aluminum, copper, chromium, and silver. In order to pattern the metal thin film into an electrode pattern shape, a photosensitive resist material is applied on the metal thin film, photomask exposure and development are performed (FIG. 11C), and a resist film 43 is formed. Next, the metal thin film is etched through the resist film (FIG. 11).
(D)). Usually, chemical etching using ferric chloride or the like is employed for the etching. If the resist is stripped, a metal electrode pattern is formed on the substrate (FIG. 11).
(E)). Usually, from the application of this resist material, exposure,
A series of steps of development, etching, and resist stripping is called “patterning”.

Next, an amorphous silicon layer 44 is formed on the metal electrode by laminating three layers in the order of n-type, i-type and p-type, and a photosensitive resist material is applied again to pattern the amorphous silicon layer. (FIG. 11F). Next, after a transparent conductive film 45 serving as an upper electrode is formed on the silicon layer, patterning is performed again to form a transparent electrode pattern (FIG. 11G). Finally, a passivation film 46 is formed to complete a thin-film solar cell pattern (FIG. 11H).

[0005]

As described above, in the conventional method of forming a thin-film solar cell by chemical etching, "patterning" has to be repeatedly performed, thus increasing the manufacturing cost of the solar cell. This is the same in the case of laser scribing and the like. Therefore, the present invention
Hydrogen in the a-Si: H layer diffuses into the palladium metal by using palladium, which is a hydrogen storage metal, as the base electrode and applying energy from the transparent electrode side using a laser or a thermal head. Focusing on the property that the interstitial distance of the metal opens and the palladium layer is easy to peel off,
At the same time when the metal layer is peeled off, the a-Si: H layer and the transparent electrode layer formed on the palladium layer are peeled off together to form a solar cell. Thereby, patterning during the solar cell manufacturing process can be performed without relying on the etching.

[0006]

The first aspect of the present invention to solve the above problems is to form a first electrode layer, an amorphous silicon layer, and a transparent second electrode layer on an insulating base material from the base material side. An amorphous silicon thin-film solar cell, characterized in that a palladium layer patterned by applying heat to the first electrode layer is used in the thin-film solar cell formed in this order. Since such a solar cell is used, thin-film solar cells can be mass-produced at low cost.

[0007] The second aspect of the present invention to solve the above problems is as follows.
Forming a first electrode layer, an amorphous silicon layer, and a transparent second electrode layer in this order on the insulating base material from the base material side, and providing a third electrode layer on the opposite surface of the insulating base material; The first three electrode layers pass through the first connection hole penetrating the second electrode layer and the base material, the first electrode layer, and the amorphous silicon photoelectric conversion layer.
The third electrode layer penetrates the first electrode layer and at least the base material in a region that is connected to the electrode layer in an insulated state and is separated from a region of the third electrode layer that is connected to the second electrode layer. An amorphous silicon thin-film solar cell, wherein a palladium layer patterned by applying heat to the first electrode layer is used in the thin-film solar cell connected through the second connection hole. Since such a solar cell is used, thin-film solar cells can be mass-produced at low cost.

[0008] The third aspect of the present invention to solve the above problems is as follows.
Comprises depositing palladium as a first electrode layer on an insulating base material, forming a transparent second electrode layer on the first electrode layer with an amorphous silicon layer interposed therebetween, and then forming the first electrode The hydrogen of the amorphous silicon layer is diffused into the palladium layer of the layer, and heat is applied to weaken the thin palladium layer and separate it. At the same time, the amorphous silicon layer on the palladium layer and the transparent second electrode are separated and patterned. A method for forming an amorphous silicon thin-film solar cell, comprising the steps of: With this method of forming a solar cell, thin-film solar cells can be mass-produced at low cost.

A fourth aspect of the present invention for solving the above-mentioned problems is as follows.
Comprises depositing palladium to be a first electrode layer on an insulating base material, providing a transparent second electrode layer on the first electrode layer with an amorphous silicon layer interposed therebetween, A third electrode layer is provided on the opposite surface, and the third electrode layer is formed through a first connection hole penetrating the base material, the first electrode layer, and the amorphous silicon layer.
The electrode layer and the second electrode layer are connected to the first electrode layer in an insulated state, and the third electrode layer is separated from the region where the third electrode layer is connected to the second electrode layer. In the method for forming a thin-film solar cell, in which the layer and the first electrode layer are connected through at least a second connection hole penetrating the base material,
Hydrogen of the amorphous silicon layer is diffused into the palladium layer of the electrode layer, and heat is applied to weaken the thin palladium layer and peel it off, and at the same time peel off the amorphous silicon layer on the palladium layer and the transparent second electrode to pattern it And a method of forming an amorphous silicon thin film solar cell. With this method of forming a solar cell, thin-film solar cells can be mass-produced at low cost.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a novel solar cell and a method for forming the same. The metal electrode layer, the amorphous silicon layer, and the transparent electrode layer on the substrate side constituting the solar cell are etched or laser-patterned. It is characterized in that a pattern is formed by using palladium, which is a hydrogen storage metal, for the substrate-side electrode without using it.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. FIG. 1 is a plan view showing an example of the thin-film solar cell of the present invention. The thin-film solar cell 1 of the present invention comprises:
A palladium layer serving as a substrate-side first electrode, an a-Si: H layer, and a transparent second electrode layer are sequentially laminated on an insulating substrate 11, and a third electrode layer is formed on the back surface of the substrate. Form. A first connection hole 14 serving as a current collection hole and a second connection hole 15 serving as a series connection hole are formed at both side edges of the base material in the insulating base material 11. The first connection hole 14 is a through hole for connecting the second electrode layer and the third electrode layer, and the second connection hole 15
Are perforated on both side edges of the substrate on which the third electrode layer is not formed, and connect the first electrode layer on the upper surface of the substrate to the third electrode layer on the lower surface of the substrate. In each case, conduction is achieved by a conductive layer passing through the connection hole. The reason for providing the third electrode layer is to reduce the Joule loss by replacing the current flowing through the transparent electrode layer with the current flowing through the third electrode layer because the transparent conductive material serving as the second electrode layer has a high resistance value. Things.

In FIG. 1, the inside of the rectangular portion surrounded by the dotted line represents the region where the third electrode layer 12 patterned on the lower surface of the base material exists, and the rectangular shape surrounded by the solid line. The wide region indicates a portion where the first electrode layer and the a-Si: H layer are sequentially formed on the upper surface of the base material, and is a rectangular portion inside the solid line (a portion not including the second connection hole 15). () Shows that a transparent third electrode layer is further formed by lamination. The first electrode layer made of palladium is peeled off from the surface of the base material 11 by applying heat to the laminated portion so that a
A separation line 18 formed by peeling the -Si: H layer and the second electrode layer together is formed, thereby constituting a unit solar cell. A similar separation line is also formed as a separation line 19 in the third electrode layer, but the separation line is formed by patterning using a mask means or the like when forming the electrode.

FIG. 2 is a sectional view showing a thin-film solar cell according to the present invention. FIG. 2A shows a cross section taken along the line AA in FIG. 1, and FIG. 2B shows a cross section taken along the line BB in FIG. In FIG. 2C, the relationship between the first electrode layer 16, the second electrode layer 26, and the third electrode layer 36 is clearly shown.
FIG. 2 (A) is shown by adding the elements of the series connection hole 15 of FIG. 2 (B).

As shown in FIG. 2A, a third electrode layer 36 is formed on the lower surface of the substrate 11, and a first electrode layer 16 of palladium is formed on the upper surface of the substrate 11, and the first electrode layer 16 is formed on the first electrode layer. a-S
i: An H layer 20, a transparent second electrode layer 26, and a passivation film 32 are formed. The first connection hole 14 is
In FIG. 1, the first electrode layer 16 is formed and then punched to a hole diameter of about 2 to 5 mm by punching or the like. Thereafter, the a-Si: H layer 20 is laminated by a CVD method or the like. Also adheres to the inner surface of the connection hole, and the first electrode layer 1
6 can be insulated. After that, if the second electrode layer is formed, the third electrode layer and the second electrode layer can be electrically connected.

In the first stage before the thin film is formed on the base material, the second connection hole 15 shown in FIG. 2B is formed on the side edge of the base material so as to have a hole diameter of about 2 to 5 mm by punching or the like. Perforated. Thereafter, a third electrode layer is formed on the back surface of the substrate 11 by sputtering a metal thin film such as nickel. Third
The electrode layer is formed using a mask or the like so that the unit cells have a shape separated by the separation line 19. Then, the first
An electrode layer is formed as a thin film using palladium. Since this thin film is formed by sputtering or the like, the metal thin film also adheres to the side surface in the connection hole, and conduction between the third electrode layer and the first electrode layer is obtained.

The solar cell according to the present invention is configured as shown in FIG. 2C, in which a potential is generated between the first electrode 16 and the second electrode 26, and the potential is 1 at the distance between the first connection holes 14. It constitutes a unit cell (UC). A high voltage can be obtained by continuously forming these unit cells and connecting them in series to the next unit cell. In the above, the embodiment in which the third electrode is provided on the back surface of the base material is described. The first electrode may be in the form of a patterned palladium electrode.

Next, an example of a method for forming a thin-film solar cell of the present invention will be described. The thin-film solar cell of the present invention can have various aspects. The first electrode 16, the a-Si: H layer 20, and the transparent second electrode layer 26 on the surface of the insulating substrate 11 are provided on the insulating substrate 11. An example in which the third electrodes 12 are formed by sequentially laminating and the third electrode 12 is formed on the back surface side of the base material will be described. 3 to 9
FIG. 3 is a diagram showing an example of a method for forming a thin-film solar cell of the present invention. First, as shown in FIG. 3, the first electrode layer 16 and the third electrode layer 36 are formed on the front and back of the base material 11.
The connection hole 15 is formed on the side edge of the base material 11 where the second electrode layer 26 is not formed by punching or the like, and then the third electrode layer 36 is formed as a thin film on the base material by sputtering or the like. As described above, the third electrode layer 36 is formed into a pattern using a mask so that the separation line 19 is formed. Subsequently, a thin film is formed on the first electrode layer by sputtering or the like using palladium. After that, the first connection hole 14 is punched from the first electrode surface side by punching or the like. At the time of forming the first electrode layer, palladium also adheres to the inner surface of the second connection hole, so that the third electrode layer and the first electrode layer are electrically connected. Although the connection hole adheres to the inner surface of the hole when the third electrode layer is formed, it is omitted in FIG.

Next, as shown in FIG. 4, a is formed on the first electrode layer 16.
-A thin film of the Si: H layer 20 and the transparent second electrode layer 26 is formed sequentially. At this time, since the a-Si: H layer material also adheres to the inner surface of the first connection hole, it covers the side surface of the first electrode layer 16,
It functions as an insulating layer when connecting the electrode layer and the second electrode layer. Next, when the second electrode layer 26 is formed as a thin film, the material of the second electrode layer also adheres to the inner surface of the first connection hole 14 and reaches the third electrode layer 36, so that the first electrode layer 16 is insulated. The second electrode and the third electrode are electrically connected.

The a-Si: H layer 20 has three layers (n type, i
A-Si: H layers are sequentially deposited by a CVD method or the like. Since the three a-Si: H layers may be formed as a continuous thin film, it is not necessary to use a mask or the like. Various methods are known for forming the a-Si: H layer 20, but the most frequently used method is to introduce a silane gas (SiH ₄ ) into a vacuum furnace, apply an electric field, and perform a plasma discharge on the substrate. There is a method of forming an a-Si: H thin film. At this time, when no impurities are added to the silane gas, an i-type layer can be formed, when diborane (B ₂ H ₆ ) is added as an impurity, a p-type layer can be formed, and when phosphine (PH ₃ ) is added, an n-type layer can be formed. . That is, the junction of the nip layer can be formed by switching the gas. Thus, the nip type can be formed in one reaction layer only by switching the gas, but it can also be formed continuously in a line where each layer is separated in a reaction chamber. In this case, there is an effect that the residual impurities hardly have an adverse effect. In FIG. 4, the a-Si: H layer is shown as one layer, but actually has the three layers described above.

Subsequently, a second electrode layer 26 is formed of a transparent conductive material. The second electrode layer 26 does not need to be formed in a pattern, and is formed continuously on the base material. The thin film can be formed by sputtering, electron beam evaporation, resistance heating evaporation, ion plating, or the like.

After the formation of the second electrode layer 26, a separation line 18 for separating the photoelectric conversion layer into unit cells is formed (FIG. 5). For this, as shown in FIG. 5, a means capable of applying heat, for example, a thermal head, a heat wire, or a laser beam is caused to travel along the portion to be separated. As a result, hydrogen (H) in the a-Si: H layer dissociates and diffuses into the palladium layer (FIGS. 6 and 7). As a result of hydrogen diffusion,
The interstitial distance of the palladium metal is increased, the palladium layer 16 is weakened and easily peeled from the substrate 11, and easily peeled from the substrate 11 by light vibration or wiping. At this time, the a-Si: H layer 20 and the second electrode layer 26 on the electrode layer are also peeled together, so that the separation line 18 for separating the unit cells can be formed (FIG. 8). Finally, a passivation film 32 is formed on the entire surface to complete a thin-film solar cell (FIG. 9).

FIG. 10 shows an amorphous silicon layer. This portion becomes a photovoltaic layer, and from the substrate side, n-type amorphous silicon layer 20n, i-type amorphous silicon layer 20i, p-type amorphous silicon layer 2
0p are stacked. Sunlight penetrates the transparent second electrode layer and absorbs photons, creating a pair of electrons and holes.
Due to the electric field existing inside the silicon layer, the electrons become n-type,
Since holes move to the p-type, a current is generated from the n-type to the p-type. This current is taken out and used.

<Examples of Materials> As the insulating base material, an insulating plastic film is preferably used.
Among them, films of polyimide, aramid, polyethersulfone, polyethylene terephthalate, polyethylene naphthalate, etc., having high heat resistance and high weather resistance are preferred. A film of these materials having a thickness of 20 μm
Those having a thickness of about 1.0 mm are preferably used. As the material of the first electrode layer, besides palladium, a conductive metal metal or alloy having a hydrogen absorbing property can be used. As the second electrode layer, a transparent conductive material that transmits sunlight can be used. Generally I
n ₂ O ₂ —SnO ₂ (ITO) is used, and other Zn
O, SnO ₂ or the like is used. As the third electrode layer, a conductive metal such as aluminum, silver, and copper can be used in addition to nickel.

[0024]

FIG. 3 to FIG. 1 show an embodiment of the present invention.
0 will be described. <Preparation of conductive substrate> Width 10c as insulating substrate 11
A polyimide film having a thickness of 0.5 mm and a thickness of 0.5 mm was used.
First, a pore serving as the second connection hole 15 was formed in the base material with a diameter of 2 mm. Next, a thin layer made of metallic nickel was pattern-formed on the back surface of the base material by a sputtering method to form a third back surface side electrode layer 36 on the base material. The film thickness was 500 °. Then, the first electrode layer 16 made of palladium metal is formed on the surface of the base material.
Was formed by a sputtering method. The film thickness was 500 °. Thereafter, a fine hole serving as the first connection hole 14 was formed with a diameter of 2 mm from the first electrode layer side (FIG. 3).

The respective film forming conditions are as follows. <Formation of Third Electrode Layer> (Sputtering conditions) Film forming temperature: 300 ° C. Sputter pressure: 5 mTorr DC power: 2.5 kW Ar flow rate: 100 sccm Deposition rate: 10 ° / sec (patterning) Pattern forming method: mask deposition method mask Pattern shape: Stripe shape (line and space) (100 mm between separation lines 19, separation line width 20 mm in the shape of FIG. 1) <Formation of first electrode layer> (Sputtering conditions) Film formation temperature: 300 ° C. Sputter pressure: 5 mTorr DC Power: 2.0 kw Ar flow rate: 100 sccm Deposition rate: 8Å / sec

Thereafter, the substrate is introduced into a vacuum furnace, and the CV
The a-Si: H layer 20 was formed by lamination on the palladium metal layer as the first electrode layer by Method D. The a-Si: H layer is formed by first forming an n-type a-Si: H (n) layer by P (phosphorus) doping from the substrate side, and then forming a non-doped i-type a-Si: H (i) layer. And finally forming a p-type a-Si: H (p) layer by B (boron) doping (FIG. 4).

The respective film forming conditions are as follows. (P-doped a-Si: H (n layer) film forming conditions) Film forming temperature: 300 ° C. a-Si: H / H ₂ / PH ₃ Flow rate: 10 sccm / 30 sccm / 10 sccm Film forming pressure: 50 mTorr RF power: 50 W Deposition rate: 10 ° / sec Film thickness: 500 ° (a-Si: H (i-layer) film forming conditions) Film forming temperature: 300 ° C. a-Si: H / H ₂ flow rate: 10 sccm / 50 sccm Film forming pressure: 50 mTorr RF Power: 50 W Deposition rate: 10Å / sec Film thickness: 3000Å (B ₂ H ₆ -doped a-Si: H (p layer) film formation conditions) Film formation temperature: 300 ° C. a-Si: H / H ₂ flow rate / B ₂ H ₆ : 10 sccm / 30 sccm / 5 sccm Film forming pressure: 50 mTorr RF power: 50 W Deposition rate: 10 ° / sec Film thickness: 300 °

<Formation of Second Electrode Layer> A transparent second electrode layer 26 of ITO was formed on the entire surface of the a-Si: H layer 20 by a reactive sputtering method. The film forming conditions are as follows. (Sputtering conditions) Target: In ₂ O ₃ -SnO ₂ sintered target (SnO ₂ : 10 wt%) Film forming temperature: 250 ° C. Film forming pressure: 5 mTorr DC power: 2.0 kW Ar / O ₂ Flow rate: 100 sccm / 3 sccm Deposition rate: 10Å / sec Film thickness: 1000Å

<Pattern formation> Pattern formation was performed on the palladium metal first electrode layer, a-Si: H layer, and transparent second electrode layer as follows (FIGS. 5, 6, 7, and 8). ). When a red-hot nichrome wire (φ: 0.5 mm) is brought into contact with the surface of the second electrode layer (ITO), the palladium metal of the first electrode layer becomes fine strips and floats on the polyimide film substrate. When a slight vibration is applied (or wiped with a brush), the a-Si: H
The layer and the second electrode layer were peeled off. Thereby, the separation line 1
8, a thin-film solar cell separated into unit cells was obtained.

[0030] <SN _X film formation> last SN _X by vacuum deposition by the CVD method as a passivation film 32
A thin film solar cell was completed by forming a film (FIG. 9). In addition,
The film forming conditions are as follows. (Passivation film deposition conditions) Deposition temperature: 250 ° C a-Si: H / N ₂ / NH ₃ Flow rate: 30 sccm / 500 sccm / 50 sccm Deposition pressure: 30 mTorr RF power: 250 W Deposition rate: 25 ° / sec Film thickness: 500Å

FIG. 10 is a diagram showing an amorphous silicon layer. This portion is to be a photoelectric conversion layer. From the substrate side, an n-type amorphous silicon layer 20n, an i-type amorphous silicon layer 20i, and a p-type amorphous silicon layer 2
0p are stacked. Sunlight penetrates the transparent conductive film, absorbs photons, and forms a pair of electrons and holes. However, electrons move to n-type and holes move to p-type due to an electric field existing inside the silicon substrate. A current flows from the mold to the p-type. This current is taken out and used.

AM-1 was added to the thin-film solar cell prepared above.
(Standard light source that reproduces the solar radiation spectrum on the equator)
Irradiation, the initial solar cell conversion efficiency was 8
%Met.

[0033]

As described above, since the thin-film solar cell of the present invention uses palladium, which is a hydrogen storage metal, patterning is easy. According to the formation method of the present invention,
Utilizing the properties of palladium without the need for chemical etching or laser patterning processes, the patterning of thin films is facilitated, the number of steps is greatly reduced, and capital investment, production costs and yields are improved, It can contribute to cost reduction.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of a thin-film solar cell of the present invention.

FIG. 2 is a cross-sectional view showing a thin-film solar cell of the present invention.

FIG. 3 is a view showing a first step of forming a thin-film solar cell of the present invention.

FIG. 4 is a view showing a second step of forming the thin-film solar cell of the present invention.

FIG. 5 is a view showing a third step of forming the thin-film solar cell of the present invention.

FIG. 6 is a view showing a fourth step of forming the thin-film solar cell of the present invention.

FIG. 7 is a view showing a fifth step of forming the thin-film solar cell of the present invention.

FIG. 8 is a view showing a sixth step of forming the thin-film solar cell of the present invention.

FIG. 9 is a view showing a seventh step of forming the thin-film solar cell of the present invention.

FIG. 10 is a diagram showing an amorphous silicon layer.

FIG. 11 is a view showing a conventional process of forming a thin-film solar cell.

[Explanation of symbols]

 Reference Signs List 11 base material 14 first connection hole 15 second connection hole 16 first electrode layer 18 separation line 19 separation line 20 amorphous silicon layer 26 second electrode layer 32 passivation film 36 third electrode layer 41 base material 42 electrode layer 43 resist film 44 Amorphous silicon layer 45 Transparent conductive film 46 Passivation film

Claims (4)

[Claims] 1. A thin-film solar cell in which a first electrode layer, an amorphous silicon layer, and a transparent second electrode layer are sequentially formed on an insulating substrate from the substrate side, and the first electrode layer is patterned by applying heat. An amorphous silicon thin film solar cell using the formed palladium layer. 2. A first electrode layer, an amorphous silicon layer, and a transparent second electrode layer are sequentially formed on an insulating substrate from the substrate side, and a third electrode layer is provided on the opposite surface of the insulating substrate. A third electrode layer is connected to the second electrode layer in a state of being insulated from the first electrode layer through a first connection hole penetrating the base material, the first electrode layer, and the amorphous silicon photoelectric conversion layer; Third
A thin-film solar cell in which the third electrode layer is connected to the first electrode layer at least through a second connection hole penetrating the base material in a region of the electrode layer separated from a region connected to the second electrode layer. 3. The amorphous silicon thin film solar cell according to claim 1, wherein a palladium layer patterned by applying heat is used for the first electrode layer. 3. After depositing palladium to be a first electrode layer on an insulating base material and providing a transparent second electrode layer on the first electrode layer with an amorphous silicon layer interposed therebetween, Hydrogen of the amorphous silicon layer is diffused into the palladium layer of the first electrode layer and heat is applied to weaken the thin palladium layer and separate it, and simultaneously separate the amorphous silicon layer on the palladium layer and the transparent second electrode. A method of forming an amorphous silicon thin film solar cell, comprising the step of performing patterning by using 4. A palladium layer serving as a first electrode layer is deposited on an insulating base material, and a transparent second electrode layer is provided on the first electrode layer with an amorphous silicon layer interposed therebetween. A third electrode layer is provided on the opposite surface of the substrate, and the third electrode layer and the second electrode layer are connected to each other through a first connection hole penetrating the substrate, the first electrode layer, and the amorphous silicon layer. The third electrode layer and the first electrode layer are connected in an insulated state, and in a region separated from a region where the third electrode layer and the second electrode layer are connected, the third electrode layer and the first electrode layer penetrate at least the base material. In the method for forming a thin-film solar cell connected through the two connection holes, hydrogen of the amorphous silicon layer is diffused into the palladium layer of the first electrode layer, and heat is applied to weaken the palladium thin layer to separate it. Amorphous on the palladium layer A method for forming an amorphous silicon thin film solar cell, comprising a step of patterning by peeling a silicon layer and a transparent second electrode.