JP3505201B2 - Method for manufacturing photovoltaic device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device comprising a photo-active layer made of a semiconductor and comprising a plurality of photoelectric conversion elements connected in series on a substrate. The present invention relates to an electromotive force device and a method for manufacturing the same. 2. Description of the Related Art A photovoltaic device represented by a solar cell is:
In recent years, it has become widespread until it is used as a small power source for watches and calculators, but now it sells surplus power obtained by its photovoltaic devices to electric power companies that have commercial power supply facilities. Therefore, a new development as a power source for electric power is about to begin. In particular, in photovoltaic devices using thin-film semiconductors, which have attracted attention due to their large area and ease of cost reduction, competition with commercial power costs is relatively advantageous, and the business is urgently required. Is expected. [0004] Another feature of such a thin-film semiconductor photovoltaic device is a so-called integrated structure in which a practically high voltage can be obtained 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 the present 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 forming 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 laser beam irradiation. Next, in a second step shown in FIG. 1B, on the first electrode films (32), (32),... And conductive members (33) (33)... And insulating members (34) (34)... Are formed for each first electrode from the side closer to the adjacent space. The material of the conductive member is an Ag paste or another metal paste, and the insulating member is a paste of SiO ₂ powder or another inorganic material. Then, in a third step shown in FIG.
A thin film including a semiconductor junction inside 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 a fourth step shown in FIG. 1D, a second electrode film (36) made of a metal material such as aluminum is formed on the thin film semiconductor film (35) following the thin film semiconductor film (35). I do. Next, in a fifth step shown in FIG. 1E, the thin film semiconductor film (35) and the thin film semiconductor film (35) located on the surfaces of the conductive members (33) (33) and the insulating members (34) (34). The first and second laser beams (L1) and (L2) are irradiated to the laminated portion of the second electrode film (36) from the surface side of the laminated portion. By the irradiation of the first laser beam (L1),
The irradiated portion of the second electrode film (36) and the thin film semiconductor film (35) are melted, and the molten material causes the second electrode film (36) and the first electrode film (32) of the adjacent photoelectric conversion element to be melted. Is a conductive member (3
Through 3), they are electrically connected. 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 area to be irradiated.
Is removed, and as a result, the second electrode film (36) is divided for each photoelectric conversion element. Therefore, by irradiating these laser beams, a plurality of photoelectric conversion elements on the substrate (31) are connected in series with each other, and a photovoltaic device having an integrated structure is completed. However, in the processing using the laser beam, it is necessary to strictly control the setting of various conditions such as the wavelength and the intensity of the laser beam. As a photovoltaic device using such a manufacturing method, for example, JP-A-63-1563
There are prior arts such as No. 71. However, in such a photovoltaic device, it is very difficult to adjust the above-mentioned irradiation conditions of the laser beam. Necessary molten portions are evaporated and disappear, or residues adhere to portions where the second electrode film and the semiconductor film are to be removed, which causes deterioration of characteristics of the photovoltaic device. Become. Furthermore, in the structure of the conventional photovoltaic device, a semiconductor which is usually required to be clean includes a conductive member or an insulating member made of a material completely different from that of the semiconductor. Contamination accidents from members 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, which complicates the manufacturing process due to the printing process and reduces pattern accuracy. Problems such as limitations also arise. [0015] The features of the manufacturing method of the present invention and
When forming an amorphous insulating layer on a photoactive layer, a step of dividing and arranging a first electrode film in a plurality of regions on a substrate having an insulating surface; As exposed, a step of forming a photoactive layer in each of the regions on the substrate surface, and by performing ion implantation on the exposed portion side, near the space between adjacent regions of the photoactive layer, Converting the implanted region into an amorphous insulating layer; and forming the first region on the photoactive layer of the other photoelectric conversion element.
A step of directly forming the second electrode film on the photoactive layer of the one photoelectric conversion element beyond the exposed portion of the electrode film and the amorphous insulating layer; and forming an energy beam only on the amorphous insulating layer. Irradiating the second electrode film of the irradiated portion to divide the irradiated portion. According to the method of manufacturing a photovoltaic device of the present invention, the photoactive layer is disposed in the vicinity of the adjacent space and on the exposed portion side of the first electrode film. By performing ion implantation, the photoactive layer in the implanted region is transformed into an amorphous insulating layer, and the second electrode film deposited on the insulating layer is changed only on this insulating layer from the surface energy. By removing and dividing by beam irradiation, a plurality of photoelectric conversion elements formed on the substrate can be connected in series. For this reason, since the same material as the photoactive layer is used as a starting material with respect to the insulating material required for dividing the second electrode film, SiO ₂ which is a material different from the conventional semiconductor is used. It is not necessary to use a paste or the like, which can prevent contamination of the photoactive layer. Further, since the amorphous insulating layer is formed by ion implantation, the processing accuracy of the ion implantation can be directly reflected on the control of the formation position of the insulating layer and the like, compared with the conventional screen printing method. Thus, the pattern accuracy can be dramatically improved. FIG. 1 is an element structure diagram for explaining a photovoltaic device manufactured by the manufacturing method of the present invention. In the figure, (1) indicates a substrate having an insulating surface made of glass, quartz, or the like, and (2), (2)... Indicate transparent conductive materials such as indium tin oxide and tin oxide which are separately arranged on the surface of the substrate (1). The first electrode films (3), (3)... Made of a film expose part of the first electrode films (2), (2).
a) (2a)... A photoactive layer made of a thin film semiconductor formed for each first electrode film on the first electrode film, specifically made of amorphous silicon, polycrystalline silicon, or the like. Or p
In-junction and the like are included in parallel with the film surface. As a method for producing this amorphous silicon, there are a plasma CVD method and an optical CVD method, and as a method for producing polycrystalline silicon or the like, a solid phase growth method (reference: Japanese J
ournal of Applied Physice voi. 29 No. 11, pp. 2327-23
31,1991) and laser recrystallization method (Reference: Japanese Jour)
nal of Applied Physice voi. 30 No. 12B, pp. 3700-370
3,1991). (4) (4) are amorphous insulating layers disposed in the vicinity of the adjacent space of the photoactive layer and on the exposed portions (2a) (2a)... Of the first electrode film; Specific materials include amorphous silicon carbide and amorphous silicon nitride. (5) (5) are the second electrode films of the photoelectric conversion elements, such as an aluminum film, a titanium film, or a chromium film, and this film is an amorphous insulating film between the photoelectric conversion elements. layer
(4) (4)... Are removed by irradiating the energy beam from the upper surface side, and are divided for each photoelectric conversion element. In the present invention , the second electrode film extends from one of the photoelectric conversion elements over the exposed portions (2a) (2a)... And the amorphous insulating layers (4) (4). Since it is deposited on the photoactive layer of the other photoelectric conversion element, the amorphous insulating layer
(4) By simply dividing and removing the second electrode films (5), (5) on the (4), a plurality of photoelectric conversion elements can be easily connected in series. Next, the method for manufacturing the photovoltaic device of the present invention will be described with reference to the element structure diagram for each step shown in FIG. Note that the same reference numerals in the drawing denote the same components as those in FIG. In the first step shown in FIG.
After a first electrode film made of a transparent conductive film having a thickness of about 2000 to 5000 mm is deposited thereon by a sputtering method, a vapor deposition method, or the like, 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 has a wavelength of 0.35 μm to 2.5 μm. A pulse output type with a wavelength is preferable, and a typical one is a wavelength of about 1.06 μm.
m, an energy density of 13 J / cm ² , and a pulse repetition frequency of 3 KHz. Next, in a second step shown in FIG. 2B, 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). 5000Å-100
It is formed by a plasma CVD method or the like to have a range of 000 °. In the present example, the well-known p
A type amorphous silicon film was used. Then, in the third step shown in FIG.
In order to divide the photoactive layer (3a) for each photoelectric conversion element, the photoactive layer (3a) is exposed so that a part of the first electrode film (2) is exposed.
In (a), an energy beam is applied to the vicinity of the adjacent space between the first electrode films to divide the photoactive layer. Incidentally, the energy beam in this case has a wavelength of 0.51 μm, for example.
An Ar laser with an output of 2 × 10 ³ W / cm ² and a CW is suitable. Next, in a fourth step shown in FIG. 3D, the substrate (1) is subjected to a heat treatment at a temperature in the range of 400 ° C. to 1000 ° C. for about 8 hours, so that the amorphous semiconductor Active layer (3
a) (3a) ... is polycrystallized, and subsequently the photoactive layers (3a) (3
a). A pn junction is formed inside this layer by thermally diffusing an n-type impurity such as phosphorus, which is conventionally known, from the surface side of. As a result, pn junction photoactive layers (3) (3)... Made of a polycrystalline semiconductor are obtained. Then, in a fifth step shown in FIG.
By performing ion implantation (I) (I) on the exposed portion (2a) (2a) side near the adjacent space of the photoactive layer (3) (3), Are transformed into amorphous insulating layers (4), (4),. As this ion implantation method, silicon ions, nitrogen ions, carbon ions, fluorine ions or hydrogen ions, etc. are implanted into the photoactive layer at an acceleration voltage of 30 to 100 keV. In the sixth step shown in FIG. 6F, the photoactive layer is exposed over the exposed portions (2a) (2a) of the first electrode film and the amorphous insulating layers (4) (4). Then, a second electrode (5) made of a metal such as aluminum or chromium having a thickness of 500 to 2000 mm is formed. Next, in a seventh step shown in FIG. 9G, 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,
This second electrode film is separated for each photoelectric conversion element. By this step, each photoelectric conversion element is connected in series on the substrate. Since the amorphous insulating layers (4) (4)... Are arranged under the second electrode (5) in the energy beam irradiation area, even if the energy beam exceeds the thickness of the second electrode film. Even if the irradiated object is removed, this amorphous insulating layer (4)
(4) Since the photoelectric conversion element is protected, the photoelectric conversion element can be processed without being destroyed. As a specific 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) (4) are formed in the photoactive layers (3) (3) by ion implantation.
Is provided, patterning with a conventional insulating paste or the like is unnecessary, and since the photoactive layer itself is used as a starting material for the insulating layer, there is no problem of contamination of the photoactive layer by the insulating layer. Will not occur. In this embodiment, not only the portion where the second electrode film is divided but also the adjacent electrode portion is used to form the amorphous insulating layer by ion implantation. The amorphous insulating layer was also formed at a portion facing the amorphous insulating layer for performing the above-mentioned operations, (4) '(4)'... According to FIG. This is because when the second electrode films (5) (5) ... extend to the first electrode films (2) (2) ... of the adjacent photoelectric conversion elements, the photoactive layer (3)
(3) are provided in order to reduce a leak current generated when wiring is performed along the side surface of. Further, in the embodiments of the present invention, only the photovoltaic device which generates electric power by the incidence of light from the substrate side has been described. A photovoltaic device can be implemented in a similar manner. Further, in the embodiment, a polycrystalline semiconductor is used by performing a heat treatment on the amorphous semiconductor film. However, the present invention is not limited to this. There is no problem at all. Further, a thin film semiconductor in which a semiconductor junction is formed by a polycrystalline semiconductor and an amorphous semiconductor may be used. As a technique for insulating the end of each photoactive layer of the photovoltaic device, there is Japanese Patent Publication No. 4-45990, for example, which reduces the leakage current flowing along the side of the photoactive layer. This is not an insulating material formed by energy beam processing when forming an integrated structure as in the present invention, but is completely different from the present invention. According to the method of manufacturing a photovoltaic device of the present invention, the photoactive layer is located near the adjacent space and on the exposed side of the first electrode film. By performing ion implantation, the photoactive layer in the implanted region is transformed into an amorphous insulating layer, and the second electrode film deposited on the insulating layer is irradiated with an energy beam from the surface only on the insulating layer. It is possible to remove and divide by irradiation, and a plurality of photoelectric conversion elements formed on the substrate can be connected in series. For this reason, since the same material as the photoactive layer is used as a starting material with respect to the insulating material required for dividing the second electrode film, SiO ₂ which is a material different from the conventional semiconductor is used. It is not necessary to use a paste or the like, which can prevent contamination of the photoactive layer. Further, since the amorphous insulating layer is formed by ion implantation, the processing accuracy of the ion implantation can be directly reflected in the control of the formation position of the insulating layer and the like, compared with the conventional screen printing method. Thus, the pattern accuracy can be dramatically improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of an element structure showing one embodiment of the photovoltaic device of the present invention. FIG. 2 is a sectional view of an element structure for each step for explaining a method of manufacturing a photovoltaic device of the present invention. FIG. 3 is a sectional view of an element structure for each process for explaining a method of manufacturing a conventional photovoltaic device. [Description of References] (1) ... substrate (2) ... first electrode film (2a) ... exposed portion (3) ... photoactive layer (4) ... amorphous insulating layer (5) ... second electrode film (I )… Ion implantation

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 31/04

Claims (1)

(57) Claims 1. A plurality of regions on a substrate having an insulating surface
Then, the first electrode film, the photoactive layer and the second electrode film are arranged in this order.
The stacked photoelectric conversion elements are divided and arranged.
The element is connected to one of the adjacent photoelectric converters at the adjacent space between the elements.
A first electrode film of the exchange element and a second electrode of the other photoelectric conversion element
And the film is exposed from the photoactive layer of the one photoelectric conversion element.
The photovoltaic device electrically connected at the exposed portion of the first electrode film
In a method of manufacturing a force device, a first electrode film is formed on a plurality of regions on a substrate having an insulating surface.
Dividing and arranging the surface of the substrate so that a part of the first electrode film is exposed.
Forming a photoactive layer for each of the regions ; and
By performing ion implantation on the exposed portion side,
Converting the first electrode into an amorphous insulating layer; and forming the first electrode on the photoactive layer of the other photoelectric conversion element.
One of the light beams exposing the exposed portion of the film and the amorphous insulating layer
Forming the second electrode film directly on the photoactive layer of the photoelectric conversion element;
And irradiating the energy beam only on the amorphous insulating layer
Removing the second electrode film in the irradiated portion and dividing the portion
And a method for manufacturing a photovoltaic device.