JPH0715023A - Photovoltaic device and its manufacture - Google Patents

Abstract

PURPOSE:To simply obtain a photovoltaic device of integration structure by working a plurality of photovoltaic transducers formed on a substrate, with a laser beam. CONSTITUTION:A part of optically active layer 3 is turned into an amorphous insulating layer 4 by ion implantation. A second electrode film 5 formed on the layer 4 is divided by an energy beam irradiation from the surface side of the insulating layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photovoltaic device having a photoactive layer made of a semiconductor and having a structure in which a plurality of photoelectric conversion elements are connected in series on a substrate and a method for manufacturing the photovoltaic device.

[0002]

2. Description of the Related Art Photovoltaic devices represented by solar cells are
In recent years, it has become widespread until it is used as a small power source for clocks, calculators, etc., but now it sells surplus power obtained by the photovoltaic device to a power company that has a commercial power source facility. Since it has become possible, new development is about to begin as a power source for so-called electric power.

In particular, in a photovoltaic device using a thin film semiconductor, which is attracting attention due to its large area and ease of cost reduction, the competition with commercial power cost is relatively advantageous, and therefore it is an urgent business. Is expected.

Another characteristic of the photovoltaic device using such a thin film semiconductor is a so-called integrated structure capable of obtaining a practically high voltage from one substrate. The photovoltaic device having this integrated structure has a conventionally well-known structure and is described in detail in, for example, Japanese Patent Publication No. 58-21827, Japanese Patent Publication No. 62-5353, and Japanese Patent Publication No. 62-14954.

FIG. 3 is a process diagram showing a manufacturing process of a conventional photovoltaic device having such a structure. The manufacturing process of this structure will be briefly described with reference to the same drawing. In the first step shown in FIG. 3A, a substrate (3) made of an insulating material such as glass or quartz is used.
After depositing a first electrode film made of indium tin oxide or the like on the entire surface of 1), the first electrode films (32), (32) ... Are divided into a plurality of regions by irradiation with a laser beam.

Next, in the second step shown in FIG. 3B, on the first electrode films (32), (32) ... In the vicinity of the adjacent intervals a, b ... Of the first electrode films. The conductive members (33) (33) ... And the insulating members (34) (34) ... are formed for each of the first electrodes from the side closer to the adjacent spacing portion. The material of the conductive member is Ag paste or other metal paste, and the insulating member is paste of SiO ₂ powder or other inorganic material.

Then, in the third step shown in FIG.
A thin film having a semiconductor junction on the entire surface of the substrate (31) so as to include the conductive members (33) (33), the insulating members (34) (34), and the first electrode films (32) (32). A semiconductor film (35) is formed. Examples of the thin film semiconductor film include amorphous silicon and polycrystalline silicon having a pin junction parallel to the film surface.

In the fourth step shown in FIG. 3D, a second electrode film (36) made of a metal material such as aluminum is formed on the thin film semiconductor film (35) subsequent to the thin film semiconductor film (35). To do.

Next, in a fifth step shown in FIG. 3E, the thin film semiconductor films (35) and the thin film semiconductor films (35) located on the surfaces of the conductive members (33) (33) ... And the insulating members (34) (34). The laminated body portion of the second electrode film (36) is irradiated with the first and second laser beams (L1) and (L2) from the surface side of the laminated body portion.

By irradiating the first laser beam (L1),
The second electrode film (36) and the thin film semiconductor film (35) in the irradiated portion are melted, and the melt causes the second electrode film (36) and the first electrode film (32) of the photoelectric conversion element adjacent to each other to be melted. Is the conductive member (3
It will be electrically connected via 3). Further, according to the irradiation of the second laser beam (L2), the irradiation causes the second electrode film (36) and the thin film semiconductor film (35) in the irradiation region.
Are removed, and as a result, the second electrode film (36) is divided for each photoelectric conversion element.

Therefore, by irradiating these laser beams, the plurality of photoelectric conversion elements on the substrate (31) are connected in series with each other, and the photovoltaic device having the integrated structure is completed.

However, in processing with this laser beam, it is necessary to strictly control various conditions such as the wavelength and the laser beam intensity, and as a photovoltaic device by such a manufacturing method, for example, JP-A-63-1563
There is prior art such as No. 71.

[0013]

However, in such a photovoltaic device, it is very difficult to adjust the irradiation conditions of the laser beam as described above, and it is possible that the melting necessary for electrical connection is a little. A portion of the photovoltaic device is evaporated and disappears, or a residue is attached to a portion where the second electrode film and the semiconductor film should be removed, which causes deterioration of characteristics of the photovoltaic device.

Further, in the structure of the conventional photovoltaic device, a semiconductor normally required to be in a clean state includes a conductive member or an insulating member made of a material completely different from that of the semiconductor therein. Contamination accidents from the member to the semiconductor are likely to occur, and since these members are usually used in a paste state, it is necessary to perform patterning by screen printing. There will also be problems such as limits.

[0015]

The photovoltaic device of the present invention is characterized in that a first electrode film, a photoactive layer and a second electrode film are provided in this order in a plurality of regions on a substrate having an insulating surface. The photoelectric conversion elements stacked in the above are divided and arranged, and the photoelectric conversion elements are adjacent to each other at an adjacent interval between the first electrode film of one photoelectric conversion element and the second electrode film of the other photoelectric conversion element. In a photovoltaic device electrically connected at the exposed portion of the first electrode film exposed from the photoactive layer of the one photoelectric conversion element, the photoactive layer of the one photoelectric conversion element is An amorphous insulating layer is provided on the exposed portion side of the spacing portion, and the one of the photoelectric conversion elements of the other photoelectric conversion element is provided over the exposed portion of the first electrode film and the amorphous insulating layer. The second electrode film deposited on the photoactive layer of the photoelectric conversion element is The irradiation region is removed and divided by irradiation of the energy beam on the amorphous insulating layer, and the feature of the manufacturing method of the present invention is that the amorphous insulating layer is formed on the photoactive layer. In doing so, a step of dividingly arranging the first electrode film in a plurality of regions on the substrate having an insulating surface, and photoactivating each region of the substrate surface so that a part of the first electrode film is exposed. A step of forming a layer, and a step of transforming the implanted region into an amorphous insulating layer by performing ion implantation on the exposed portion side in the vicinity of the space adjacent to the region of the photoactive layer, The second electrode film is formed on the photoactive layer of the other photoelectric conversion element over the exposed portion of the first electrode film and the amorphous insulating layer from the photoactive layer of the other photoelectric conversion element. Process and energy beam on the amorphous insulating layer A step of dividing removing the second electrode layer of the irradiated portion by irradiating is to consist of.

[0016]

According to the photovoltaic device of the present invention, an amorphous insulating layer is provided in the photoactive layer in the vicinity of the space between adjacent photoelectric conversion elements, and the second insulating layer is deposited on the amorphous insulating layer. Since the electrode film is divided by irradiating the surface of the insulating layer with an energy beam, a plurality of photoelectric conversion elements formed on the substrate can be connected in series with each other.

Therefore, according to the present invention, an amorphous insulating layer is provided at a predetermined position of the photoactive layer and is used as an insulating material at the time of energy beam irradiation. Therefore, the conventional conductive member or insulating member is used. Therefore, there is no need to use, and problems such as contamination will not occur.

Further, according to the method for manufacturing a photovoltaic device of the present invention, by performing ion implantation on the exposed portion side of the first electrode film in the vicinity of the adjacent spacing of the photoactive layer, the implantation is performed. By changing the quality of the photoactive layer in the region into an amorphous insulating layer and removing and dividing the second electrode film deposited on the insulating layer by energy beam irradiation from the surface side of this insulating layer,
It is possible to connect a plurality of photoelectric conversion elements formed on the substrate in series. Therefore, as the insulating material required for dividing the second electrode film, the same material as the photoactive layer is used as a starting material, so that a SiO ₂ paste or the like, which is a material different from a conventional semiconductor, is used. It is possible to prevent the photoactive layer from being contaminated due to the absence of the use of.

Further, since the amorphous insulating layer is formed by ion implantation, the processing accuracy of ion implantation can be directly reflected on the control of the position of formation of the insulating layer, etc. It is possible to dramatically improve the pattern accuracy.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an element structure diagram for explaining a photovoltaic device according to an embodiment of the present invention. In the figure, (1) is a substrate having an insulating surface made of glass or quartz, (2) (2) ... is a transparent conductive material such as indium tin oxide or tin oxide, which is divided and arranged on the surface of the substrate (1). First electrode film made of a film, (3) (3) ...
Is a photoactive layer made of a thin film semiconductor formed for each first electrode film so that a part of the first electrode film (2) (2) ... Is exposed (2a) (2a). It is made of crystalline silicon, polycrystalline silicon, or the like, and inside thereof includes a pn junction or a pin junction in parallel with the film surface.

As a method for producing this amorphous silicon, there are a plasma CVD method and a photo CVD method, and as a method for producing polycrystalline silicon etc., a solid phase growth method (reference: Japanese J
ournal of Applied Physice voi.29 No.11, pp.2327-23
31, 1991) and laser recrystallization (reference: Japanese Jour
nal of Applied Physice voi.30 No.12B, pp.3700〜370
3, 1991).

(4) (4) ... Amorphous insulating layers arranged in the vicinity of the adjacent space of the photoactive layer and on the exposed portions (2a) (2a) ... side of the first electrode film, Specific materials include amorphous silicon carbide and amorphous silicon nitride. (5) (5) ... is a second electrode film made of an aluminum film, a titanium film or a chrome film of the photoelectric conversion element, and this film is an amorphous insulating film between the photoelectric conversion elements. layer
(4) (4) ... Is removed by irradiation with an energy beam from the surface side above, and is divided into photoelectric conversion elements.

In the photovoltaic device of the present invention, the second electrode film is
The exposed part (2a) (2a) (2a) of the first electrode film from one photoelectric conversion element
a) ... and the amorphous insulating layers (4) (4) ... are deposited on the photoactive layer of the other photoelectric conversion element, so that the amorphous insulating layers (4) (4) A plurality of photoelectric conversion elements can be easily connected in series only by dividing and removing the second electrode films (5), (5), ... Above.

Next, a method of manufacturing the photovoltaic device of the present invention will be described with reference to the element structure diagram for each step shown in FIG. In addition, the reference numerals in the drawings are the same as those of the materials using the same materials as those in FIG.

In the first step shown in FIG. 3A, the substrate (1) is
A first electrode film made of a transparent conductive film having a film thickness of about 2000 Å to 5000 Å is deposited thereon by a sputtering method, a vapor deposition method, or the like, and then the first electrode film is irradiated with an energy beam.
(2) (2) ... Are divided and arranged for each photoelectric conversion element.

Since it is appropriate that the energy beam has a wavelength that is hardly absorbed by the substrate (1), for example, when glass is used as the substrate, the energy beam is 0.35 μm to 2.5 μm. A pulse output type of wavelength is preferable, and a typical one is a wavelength of about 1.06μ.
m, an energy density of 13 J / cm ² , and a pulse repetition frequency of 3 KHz, which is an Nd: YAG laser with a Q switch.

Next, in the second step shown in FIG. 3B, a photoactive layer (3a) made of an amorphous semiconductor is formed on the entire surface of the substrate so as to include the first electrode films (2) (2). Film thickness is 5000Å-100
It is formed by a plasma CVD method or the like so as to have a range of 000Å. In this example, as the amorphous semiconductor, a conventionally known p
Type amorphous silicon film was used.

Then, in the third step shown in FIG.
In order to divide the photoactive layer (3a) into photoelectric conversion elements, the photoactive layer (3a) is exposed so that a part of the first electrode film (2) is exposed.
The energy beam is radiated to the vicinity of the adjacent space of the first electrode film in a) to divide the photoactive layer. Incidentally, the energy beam in such a case has a wavelength of 0.51 μm, for example.
m, an output of 2 × 10 ³ W / cm ² , and a CW Ar laser are suitable.

Next, in the fourth step shown in FIG. 3D, the substrate (1) is subjected to heat treatment for about 8 hours in the temperature range of 400 ° C. to 1000 ° C. Active layer (3
a) (3a) ... is polycrystallized, and subsequently the photoactive layer (3a) (3a)
A n-type impurity such as conventionally known phosphorus is thermally diffused from the surface side of a) to form a pn junction inside this layer. As a result, pn junction photoactive layers (3), (3) ... Of polycrystalline semiconductor are obtained.

Then, in the fifth step shown in FIG.
By performing ion implantation (I) (I) on the exposed portions (2a) (2a) ... side of the photoactive layers (3) (3). The end portions of are transformed into amorphous insulating layers (4) (4).

As the ion implantation method, silicon ions, nitrogen ions, carbon ions, fluorine ions or hydrogen ions are implanted into the photoactive layer at an accelerating voltage of 30 to 100 keV.

In the sixth step shown in FIG. 3F, the photoactive layer is crossed over the exposed portions (2a) (2a) of the first electrode film and the amorphous insulating layers (4) (4). Then, a second electrode (5) having a film thickness of 500Å to 2000Å and made of metal such as aluminum or chromium is formed.

Next, in the seventh step shown in FIG. 7G, the amorphous insulating layer is formed on the amorphous insulating layers (4), (4).
(4) By irradiating the energy beam (EB) from the surface side of (4) ..., the second electrode film (5) in the irradiated portion is removed,
The second electrode film is separated for each photoelectric conversion element. Through this step, the photoelectric conversion elements are connected in series on the substrate.

Since the amorphous insulating layers (4), (4) ... Are arranged under the second electrode (5) in the irradiation region of this energy beam, even if the energy beam exceeds the thickness of the second electrode film. , Even if the object to be irradiated is removed, this amorphous insulating layer (4)
Since the photoelectric conversion element is protected by (4) ..., the photoelectric conversion element can be processed without being destroyed.

As this concrete energy beam, for example, a YAG laser having a wavelength of 1.06 μm can be used.

Therefore, according to the manufacturing method of the present invention, the amorphous insulating layers (4) and (4) are formed in the photoactive layers (3) (3) by ion implantation.
Since the ... is provided, patterning with an insulating paste or the like as in the past is unnecessary, and since the photoactive layer itself is used as a starting material for the insulating layer, there is a problem of contamination of the photoactive layer by the insulating layer. It will not occur.

Incidentally, in the present embodiment, not only the portion for dividing the second electrode film as the portion for forming the amorphous insulating layer by the ion implantation but also the second electrode is divided at the adjacent space portion. The amorphous insulating layer was formed also in the portion facing the amorphous insulating layer for the purpose, that is, (4) '(4)' in FIG. This is because when the second electrode films (5) (5) ... Extend to the first electrode films (2) (2) ... of the adjacent photoelectric conversion element, the photoactive layer (3)
(3) It is provided in order to reduce the leakage current generated when the wiring is provided along the side surface of.

Further, in the embodiments of the present invention, only the photovoltaic device for generating power by light incident from the substrate side has been described, but the present invention is not limited to this, and power is generated by light incidence from the film forming surface side. The same can be applied to the photovoltaic device. Further, in the embodiment, a polycrystalline semiconductor is used by subjecting an amorphous semiconductor film to heat treatment, but the present invention is not limited to this, and a normal amorphous state may be used as a photoactive layer. There is no problem. Further, a thin film semiconductor having a semiconductor junction formed of a polycrystalline semiconductor and an amorphous semiconductor may be used.

As a technique for insulating the ends of the photoactive layers of the photovoltaic device, there is, for example, Japanese Patent Publication No. 4-45990, which reduces the leakage current flowing along the side surface of the photoactive layer. This is for the purpose of making it an insulating material by energy beam processing when forming an integrated structure as in the present invention, and is completely different from the present invention.

[0040]

According to the photovoltaic device of the present invention, an amorphous insulating layer is provided in the photoactive layer in the vicinity of the space adjacent to the photoelectric conversion element, and the amorphous insulating layer is deposited on the amorphous insulating layer. Since the second electrode film is divided by irradiating an energy beam from the surface side on the insulating layer, it is possible to connect a plurality of photoelectric conversion elements formed on the substrate in series with each other. Become.

Therefore, according to the present invention, an amorphous insulating layer is provided at a predetermined position of the photoactive layer and is used as an insulating material at the time of energy beam irradiation. Does not need to be used, and problems such as contamination do not occur. .

Further, according to the method for manufacturing a photovoltaic device of the present invention, by performing ion implantation on the exposed portion side of the first electrode film in the vicinity of the adjacent spacing of the photoactive layer, the implantation is performed. By changing the quality of the photoactive layer in the region into an amorphous insulating layer and removing and dividing the second electrode film deposited on the insulating layer by energy beam irradiation from the surface side of this insulating layer,
It is possible to connect a plurality of photoelectric conversion elements formed on the substrate in series. Therefore, as the insulating material required for dividing the second electrode film, the same material as the photoactive layer is used as a starting material, so that a SiO ₂ paste or the like, which is a material different from a conventional semiconductor, is used. Therefore, it is possible to suppress the contamination of the photoactive layer due to the use of the.

Furthermore, since the above-mentioned amorphous insulating layer is formed by ion implantation, the processing precision of ion implantation can be reflected as it is in the formation position control of the insulating layer, etc. It is possible to dramatically improve the pattern accuracy.

[Brief description of drawings]

FIG. 1 is a sectional view of an element structure showing an embodiment of a photovoltaic device of the present invention.

FIG. 2 is a sectional view of the element structure for each step for explaining the method for manufacturing the photovoltaic device of the present invention.

FIG. 3 is a sectional view of an element structure for each step for explaining a method for manufacturing a conventional photovoltaic device.

[Explanation of symbols]

(1) ... Substrate (2) ... First electrode film (2a) ... Exposed part (3) ... Photoactive layer (4) ... Amorphous insulating layer (5) ... Second electrode film (I) ... Ion implantation

Claims (2)

[Claims] 1. A photoelectric conversion element in which a first electrode film, a photoactive layer, and a second electrode film are laminated in this order is divided and arranged in a plurality of regions on a substrate having an insulating surface, and the photoelectric conversion elements are The first electrode film of one of the photoelectric conversion elements and the second electrode film of the other photoelectric conversion element, which are adjacent to each other, are exposed from the photoactive layer of the one photoelectric conversion element in the adjacent space between the elements. In the photovoltaic device electrically connected to the exposed portion of the one-electrode film, the photoactive layer of the one photoelectric conversion element includes an amorphous insulating layer on the exposed portion side of the adjacent spacing portion, The second electrode deposited on the photoactive layer of the other photoelectric conversion element beyond the exposed portion of the first electrode film and the amorphous insulating layer on the photoactive layer of the other photoelectric conversion element. The film is irradiated with an energy beam on the amorphous insulating layer. Photovoltaic device, characterized in that frequency is divided is removed. 2. A photoelectric conversion element in which a first electrode film, a photoactive layer and a second electrode film are laminated in this order is divided and arranged in a plurality of regions on a substrate having an insulating surface, and the photoelectric conversion elements are The first electrode film of one of the photoelectric conversion elements and the second electrode film of the other photoelectric conversion element, which are adjacent to each other, are exposed from the photoactive layer of the one photoelectric conversion element in the adjacent space between the elements. In a method of manufacturing a photovoltaic device electrically connected to an exposed portion of one electrode film, a step of dividingly arranging the first electrode film in a plurality of regions on a substrate having an insulating surface; A step of forming a photoactive layer in each of the regions on the surface of the substrate so that a part of the region is exposed, and ion implantation is performed on the exposed portion side in the vicinity of the adjacent spacing of the regions of the photoactive layer. A step of transforming the implantation region into an amorphous insulating layer by applying And the second electrode film on the photoactive layer of the other photoelectric conversion element over the exposed portion of the first electrode film and the amorphous insulating layer from the photoactive layer of the other photoelectric conversion element. A method of manufacturing a photovoltaic device, comprising: a step of forming; and a step of irradiating the amorphous insulating layer with an energy beam to remove and divide the second electrode film in the irradiated portion.