JP2010010606A - Optical conversion element cell, integrated optical conversion device, method of manufacturing optical conversion element cell, and method of manufacturing integratedoptical conversion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an integrated optical conversion device which uses a high-performance optical conversion element cell, and a method of manufacturing the integrated optical conversion device that decreases the number of processes and reduces the cost. <P>SOLUTION: The optical conversion element cell 20 includes a plurality of unit cell elements 15a, 15b, 15c and 15d which are insulated and separated on a common substrate 8 with separation grooves 14a, 14b and 14c having a predetermined width, and electrically connected in series, each of the unit cell elements comprising a back electrode layer formed on the substrate 8 and provided with a back electrode lead-out portion, a crystalline semiconductor layer formed on a surface of a part, other than the back electrode lead-out portion, of the back electrode layer, and generating a pn junction by light irradiation, and a transparent surface electrode layer formed on the crystalline semiconductor layer and provided with a grid electrode. A plurality of optical conversion element cells 20 are electrically connected in series to obtain the integrated optical conversion device. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical conversion element cell and the like, and more particularly to an optical conversion element cell and the like used for a solar cell module.

Natural disasters are starting to occur around the world due to the effects of global warming. Under these circumstances, interest in energy and environmental issues has increased, and people around the world are beginning to recognize the importance of clean and sustainable renewable energy. Solar power generation is the most promising energy source. Against this background, research and development for practical application of solar cells has progressed, and the solar cell industry is growing rapidly.
The main solar cell is a crystalline silicon solar cell based on a wafer. From the viewpoint of high cost, a thin film solar cell in which the film thickness of the optical conversion layer can be made relatively thin is drawing attention.

  Each of the solar cells is called a unit cell element, and its size is about 10 cm square. Therefore, in order to extract large electric power, an optical conversion element cell is formed by connecting a plurality of unit cell elements in series. Further, an integrated thin film solar cell (solar cell module) manufactured by connecting them is common.

  As a method for manufacturing such an integrated thin film solar cell, for example, in Patent Document 1, adjacent solar cell arrays are individually manufactured in advance and the adjacent solar cells are electrically connected after the solar cell arrays are electrically connected. Effective insulation ratio of power generation by preventing the occurrence of short circuit due to migration, etc. by electrically insulating the gap between the arrays and the periphery of the members that are connected in series between the solar cell arrays with an adhesive resin sealing material A manufacturing method of a solar cell module having a high height is described.

JP 2003-124482 A

By the way, a CIS thin film solar cell using a chalcopyrite type compound semiconductor for a light absorption layer is usually manufactured by the following procedure.
FIG. 4 is a diagram for explaining a manufacturing process of a conventional CIS thin film solar cell. First, after the strip-shaped back electrode layer 2 is formed on the insulating substrate 1 (FIG. 4A), the crystalline semiconductor layer 3 is formed by sputtering or the like (FIG. 4B), Subsequently, the crystalline semiconductor layer 3 is striped by a mechanical pattern method (FIG. 4C), and then a transparent surface electrode layer 4 is formed (FIG. 4D). Finally, a transparent surface electrode is formed. The layer 4 is divided into strips (FIG. 4E).
In order to increase the area of the solar cell, the unit cell is connected in series by connecting the transparent surface electrode layer 4 of each divided unit cell to the back electrode layer 2 of the adjacent unit cell.

However, the above-described manufacturing method has a problem that the number of steps is large and the manufacturing cost increases because it is necessary to repeat the film formation and patterning operations a plurality of times.
An object of the present invention is to provide an integrated optical conversion device using a high-performance optical conversion element cell and a method for manufacturing an integrated optical conversion device with a small number of steps and low cost.

According to the present invention, there is provided an optical conversion element cell having a plurality of unit cell elements formed on a common substrate, which is electrically isolated in series by a substrate and a separation groove having a predetermined width on the substrate. A plurality of unit cell elements connected to the back surface electrode layer formed on the substrate and provided with a back electrode extraction portion; and a portion of the back electrode layer other than the back electrode extraction portion An optical conversion element comprising: a crystalline semiconductor layer which is formed on a surface and generates a pn bond by light irradiation; and a transparent surface electrode layer formed on the crystalline semiconductor layer and provided with a grid electrode A cell is provided.
Here, the crystalline semiconductor layer is preferably composed of a thin film made of a Cu—In—Se based semiconductor material having a chalcopyrite structure containing at least copper (Cu), indium (In), and selenium (Se).
Further, the unit cell element formed on the common substrate and the other unit cell elements adjacent to each other with the separation groove interposed therebetween are positioned so that the back electrode extraction portions provided in the unit cell elements are rotated 180 degrees relative to each other. It is preferable to arrange | position.

  According to the present invention, there is provided an integrated optical conversion device comprising a plurality of the above-described optical conversion element cells, wherein the plurality of optical conversion element cells are integrated by being electrically connected in series. Provided.

  Next, according to the present invention, there is provided a method for manufacturing an optical conversion element cell having a plurality of unit cell elements on a common substrate, wherein a back electrode layer, a crystalline semiconductor layer, and a transparent surface electrode layer are formed on the substrate. A thin film laminating step for sequentially laminating, an electrode extracting portion forming step for forming a back electrode extracting portion in a part of the formed back electrode layer, and a separation groove reaching the substrate from the transparent surface electrode layer laminated on the substrate A unit cell element isolation step for forming a plurality of unit cell elements insulated and separated with a predetermined width of the isolation groove; and a connection step for electrically connecting the formed unit cell elements in series. A method for manufacturing an optical conversion element cell is provided.

  Here, in the method of manufacturing an optical conversion element cell to which the present invention is applied, the electrode extraction portion forming step includes coating a part of the formed back electrode layer with an adhesion mask, and then forming a crystal on the back electrode layer. It is preferable to laminate | stack a quality semiconductor layer and a transparent surface electrode layer in order.

  Further, in the method of manufacturing an optical conversion element cell to which the present invention is applied, the electrode extraction portion forming step includes a crystalline semiconductor layer comprising a back electrode layer, a crystalline semiconductor layer, and a transparent surface electrode layer laminated on the substrate. It is preferable to remove a part of the transparent surface electrode layer.

  According to the present invention, there is provided a method of manufacturing an integrated optical conversion device in which optical conversion element cells are integrated, and a plurality of optical conversion element cells manufactured by the method of manufacturing an optical conversion element cell are electrically connected. There is provided a method of manufacturing an integrated optical conversion device, wherein the integrated optical conversion devices are integrated by connecting them in series.

  ADVANTAGE OF THE INVENTION According to this invention, the high performance optical conversion element cell which has a compound semiconductor thin film, and the integrated optical conversion apparatus which connected this in series can be manufactured with few processes and low cost.

  Hereinafter, embodiments of the present invention will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary. Further, the drawings to be used are for explaining the present embodiment and do not represent the actual size.

FIG. 1 is a diagram illustrating an example of the optical conversion element cell 20. As shown in FIG. 1, the optical conversion element cell 20 has four unit cell elements (15a, 15b, 15c, 15d) formed on a common substrate 8. These unit cell elements (15a, 15b, 15c, 15d) are insulated and separated at predetermined intervals by three separation grooves (14a, 14b, 14c) provided on the substrate 8.
The width of the separation grooves (14a, 14b, 14c) is not particularly limited, but is about 100 μm in the present embodiment.

Next, the unit cell elements (15a, 15b, 15c, 15d) will be described.
The unit cell elements (15a, 15b, 15c, 15d) formed on the common substrate 8 are respectively formed on the substrate 8 and provided with back electrode layers (9a, 91c) provided with back electrode extraction portions (91a, 91c). 9b, 9c, 9d) and a crystalline semiconductor layer which is formed on the surface of the back electrode layer (9a, 9b, 9c, 9d) other than the back electrode take-out portion (91a, 91c) and generates a pn bond by light irradiation (10a, 10b, 10c, 10d) and transparent surface electrode layers (11a, 10b, 112c, 112d) formed on the crystalline semiconductor layers (10a, 10b, 10c, 10d) and provided with grid electrodes (112a, 112b, 112c, 112d) 11b, 11c, 11d). In addition, extraction electrodes (92a, 92c) are formed in the back electrode extraction portions (91a, 91c), respectively.
Although not shown, the back electrode layers (9b, 9d) of the unit cell elements (15b, 15d) are also provided with back electrode take-out portions, and take-out electrodes are formed in the back electrode take-out portions. Has been.

As shown in FIG. 1, the arrangement of the back electrode extraction portions (91a, 91c) provided in the unit cell elements (15a, 15b, 15c, 15d) is such that each unit cell element can efficiently extract current. It arrange | positions at the edge part of (15a, 15b, 15c, 15d).
Similarly, grid electrodes (112a, 112b, 112c, 112d) are provided at the ends of the transparent surface electrode layers (11a, 11b, 11c, 11d) of the unit cell elements (15a, 15b, 15c, 15d), respectively. .

  Further, for example, the unit cell element 15a and the other unit cell element 15b adjacent to each other with the separation groove 14a interposed therebetween are a back electrode extraction portion 91a provided in the unit cell element 15a and a back electrode extraction provided in the unit cell element 15b. The parts (not shown) are arranged so as to be rotated 180 degrees relative to each other.

  By connecting the extraction electrode 92a formed on the back surface electrode extraction portion 91a of the unit cell element 15a and the grid electrode 112b formed on the transparent surface electrode layer 11b of the unit cell element 15b with a metal wire 12ab, the unit cell element 15a The unit cell element 15b is electrically connected in series.

  Similarly, the unit cell element 15b is connected to the unit cell element 15b by connecting the take-out electrode (not shown) of the unit cell element 15b and the grid electrode 112c formed on the transparent surface electrode layer 11c of the unit cell element 15c with a metal wire 12bc. The cell element 15c is electrically connected in series. Further, the unit cell element 15c and the unit cell element 15d are connected by connecting the extraction electrode 92c of the unit cell element 15c and the grid electrode 112d formed on the transparent surface electrode layer 11d of the unit cell element 15d with a metal wire 12cd. Electrically connected in series.

In this way, the four unit cell elements (15a, 15b, 15c, 15d) formed on the common substrate 8 and insulated and separated by the separation grooves (14a, 14b, 14c) are electrically connected in series. The optical conversion element cell 20 is configured.
Furthermore, an integrated optical conversion device (not shown) is obtained by electrically connecting a plurality of other optical conversion element cells having the same structure as the optical conversion element cell 20 in series.

Next, components of the optical conversion element cell 20 will be described.
As a material which comprises the board | substrate 8, metal films, such as stainless steel, an organic film, glass etc. are mentioned, for example. Although the magnitude | size of the board | substrate 8 is not specifically limited, In this Embodiment, length x width is 10 cm x 10 cm, and thickness is 0.5 mm.
The material constituting the back electrode layer (9a, 9b, 9c, 9d) is preferably a metal, for example, at least one metal selected from Mo, Ti, Cr, Al, Ag, Au, Cu and Pt, or these These alloys are mentioned. The back electrode layers (9a, 9b, 9c, 9d) are metal thin films having a thickness of about 0.3 μm in the present embodiment. The back electrode layers (9a, 9b, 9c, 9d) are formed by, for example, a vapor deposition method, a sputtering method, a CVD method (Chemical Vapor Deposition), or the like.

Examples of the crystalline semiconductor layers (10a, 10b, 10c, 10d) include chalcopyrite type compound semiconductors containing elements from groups IB, IIIB, and VIB of the periodic table. In this embodiment mode, it is preferably formed using a Cu—In—Se semiconductor material having a chalcopyrite structure including copper (Cu), indium (In), and selenium (Se).
Here, when a Cu—In—Se based semiconductor material is employed, a p-type semiconductor formed of a mixture of Cu and Se that is easy to form a p-type semiconductor on the back electrode layer (9a, 9b, 9c, 9d) side. N-type semiconductor forming precursor comprising a mixture of In and Se that is easy to form an n-type semiconductor on the transparent surface electrode layer (11a, 11b, 11c, 11d) side. It is preferable to form a layer. The p-type semiconductor forming precursor layer and the n-type semiconductor forming precursor layer melt and diffuse to each other, thereby producing crystalline semiconductor layers (10a, 10b, 10c, 10d) having good crystallinity. A pn junction can be formed.
The thickness of the crystalline semiconductor layers (10a, 10b, 10c, 10d) is in the range of 0.3 μm to 5 μm in the present embodiment.

In the present embodiment, the transparent surface electrode layers (11a, 11b, 11c, and 11d) are made of a metal material including at least one selected from ITO (Indium Tin Oxide), SiO ₂ , and ZnO, and are formed by sputtering or vapor deposition. It is preferable to form a film by. The thickness of the transparent surface electrode layers (11a, 11b, 11c, 11d) is about 0.6 μm in the present embodiment.
The grit electrodes (112a, 112b, 112c, 112d) are formed as comb-shaped metal electrodes including at least one metal selected from Al, Ag, Au, Cu, and Pt, or an alloy thereof, for example.
The extraction electrodes (92a, 92c) (however, although not shown, include the extraction electrodes provided on the back electrode layers 9b, 9d) are, for example, at least one metal selected from Al, Ag, Cu, and Pt, or these It is formed using the alloy.
As the metal wires (12ab, 12bc, 12cd), for example, Au, Al, or the like can be used.

Next, a method for manufacturing the optical conversion element cell 20 will be described. The same components as those in FIG.
FIG. 2 is a diagram for explaining the first embodiment of the method for manufacturing the optical conversion element cell 20. As shown in FIG. 2A, a back electrode layer 9 made of a metal thin film is formed on the substrate 8 by sputtering. Next, as shown in (1) and (2) of FIG. 2B, a part of the formed back electrode layer 9 is covered with a deposition mask (16a, 16b, 16c, 16d), and then the back surface On the electrode layer 9, a semiconductor precursor layer 101 for forming a crystalline semiconductor layer and a transparent surface electrode layer 11 are sequentially laminated by sputtering. In this embodiment, the semiconductor precursor layer 101 is formed by stacking a plurality of p-type semiconductor forming precursor layers and n-type semiconductor forming precursor layers.
In addition, (2) of FIG.2 (b) is a top view explaining the position of a deposition mask (16a, 16b, 16c, 16d). In the present embodiment, the deposition masks (16a, 16b, 16c, 16d) need to be aligned with high precision, but it is not necessary to perform patterning many times.

  Subsequently, as shown in (1) and (2) of FIG. 2 (c), the transparent surface electrode layer 11 (see FIG. 2 (b)) to the back electrode layer 9 (see FIG. 2 (b)) using a YAG laser. Are etched to form three separation grooves (14a, 14b, 14c) having a predetermined width, and four unit cell elements (15a, 15b, 14c) insulated and separated by the separation grooves (14a, 14b, 14c). 15c, 15d). Thereafter, infrared rays are irradiated for a certain period of time, and a plurality of precursor layers constituting the semiconductor precursor layer 101 are mutually melted and diffused to prepare a crystalline semiconductor layer (10d) in which a pn junction is formed.

  Next, as shown in (1) and (2) of FIG. 2 (d), the extraction electrode of the unit cell element (15a, 15b, 15c, 15d) and the grid electrode of another adjacent unit cell element are made of metal. An optical conversion element cell in which four unit cell elements (15a, 15b, 15c, 15d) are electrically connected in series is prepared by bonding with wires (12ab, 12bc, 12cd).

Next, another manufacturing method of the optical conversion element cell 20 will be described. The same components as those in FIG.
FIG. 3 is a diagram for explaining a second embodiment of the method for manufacturing the optical conversion element cell 20. The same components as those in FIG.
First, as shown in FIG. 3A, a semiconductor precursor layer 101 and a transparent surface electrode layer 11 for forming a back electrode layer 9 made of a metal thin film and a crystalline semiconductor layer on a substrate 8 by sputtering. Are sequentially stacked.

  Next, as shown in (1) and (2) of FIG. 3 (b), a part of the surface of the formed transparent surface electrode layer 11 was covered with a deposition mask (17a, 17b, 17c, 17d). Thereafter, by laser cutting or etching, a range corresponding to a portion of the laminated transparent surface electrode layer 11 and semiconductor precursor layer 101 that forms a separation groove and a back electrode extraction portion described later is removed.

Subsequently, as shown in (1) and (2) of FIG. 3 (c), the portions (18a, 18b, 18c, 18d) for forming the back electrode extraction portion on the surface of the back electrode layer 9 are left, and the back surface The part of the electrode layer 9 where the separation groove is formed is removed, three separation grooves (14a, 14b, 14c) having a predetermined width are formed, and the unit cell elements are insulated and separated.
Thereafter, infrared rays are irradiated for a certain period of time, and a plurality of precursor layers constituting the semiconductor precursor layer 101 are mutually melted and diffused to prepare a crystalline semiconductor layer (10d) in which a pn junction is formed.

  Next, as shown in (1) and (2) of FIG. 3 (d), the extraction electrode of the unit cell element (15a, 15b, 15c, 15d) and the grid electrode of another adjacent unit cell element are made of metal. An optical conversion element cell is prepared in which four unit cell elements (15a, 15b, 15c, 15d) are electrically connected in series by being coupled by wires (12ab, 12bc, 12cd).

Below, based on an Example, this invention is demonstrated further in detail. The present invention is not limited to the following examples.
The optical conversion element cell which has four unit cell elements was prepared with the following procedures using the Cu-In-Se type | system | group semiconductor material which has a chalcopyrite structure. Furthermore, an integrated optical conversion device integrated was prepared by electrically connecting 16 of the prepared optical conversion element cells in series.

(Preparation of optical conversion element cell)
Through the following operations, a back electrode layer, a semiconductor precursor layer, and a transparent surface electrode layer were continuously formed on the substrate by sputtering. First, a Mo thin film (film thickness: 0.3 μm) was formed as a back electrode layer by sputtering on a glass substrate (vertical × horizontal: 10 cm × 10 cm) in a vacuum chamber. Subsequently, after depositing a deposition mask on the portion of the back electrode layer formed in the vacuum chamber where the back electrode extraction portion is to be formed, a p-type semiconductor forming precursor layer and an n-type semiconductor forming precursor layer are formed by sputtering. Were deposited (total film thickness 0.5 μm). Further, an Al—Zn—O thin film (film thickness: 0.6 μm) was formed thereon as a transparent surface electrode layer by sputtering.

  Subsequently, a crystal in which a pn junction is formed by irradiating infrared rays from the transparent surface electrode layer side for a certain period of time and melting and diffusing the p-type semiconductor forming precursor layer and the n-type semiconductor forming precursor layer mutually. A quality semiconductor layer was prepared. Thereafter, a comb-shaped grid electrode for collecting current was placed on the transparent surface electrode layer, and a take-out electrode was placed on the back-side electrode take-out portion of the back-side electrode layer by printing with sputtering or conductive paste, respectively.

Next, etching was performed from the transparent front electrode layer to the back electrode layer with a YAG laser to form three separation grooves having a width of 100 μm, and four unit cell elements insulated and separated by the separation grooves were formed. Subsequently, an extraction electrode of the unit cell element and a grid electrode of another adjacent unit cell element were coupled by a metal wire to prepare an optical conversion element cell in which four unit cell elements were electrically connected in series.
Further, the 16 optical conversion element cells prepared were electrically connected in series and integrated to prepare an integrated optical conversion device.

The conversion efficiency of the optical conversion element cell in which the four unit cell elements were electrically connected in series was 7.3% as a result of measurement by two-terminal measurement.
Further, the conversion efficiency of the integrated optical conversion device in which 16 optical conversion element cells were electrically connected in series and integrated was 7.4%.
As described above, by consistently forming the back electrode layer, the semiconductor precursor layer, and the transparent surface electrode layer on the substrate, the number of manufacturing steps of the integrated optical conversion device can be reduced. It can be seen that a high-performance integrated optical conversion device using a Cu—In—Se based semiconductor material can be obtained.

It is a figure explaining an example of an optical conversion element cell. It is a figure explaining 1st Embodiment of the manufacturing method of an optical conversion element cell. It is a figure explaining 2nd Embodiment of the manufacturing method of an optical conversion element cell. It is a figure explaining the manufacturing process of the conventional CIS thin film type solar cell.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,8 ... Substrate, 2, 9, 9a, 9b, 9c, 9d ... Back electrode layer, 3, 10a, 10b, 10c, 10d ... Crystalline semiconductor layer, 4, 11a, 11b, 11c, 11d ... Transparent surface electrode Layer, 12ab, 12bc, 12cd ... metal wire, 14a, 14b, 14c ... separation groove, 15a, 15b, 15c, 15d ... unit cell element, 20 ... optical conversion element cell, 91a, 91c ... back electrode extraction part, 112a, 112b, 112c, 112d ... grid electrodes

Claims (8)

An optical conversion element cell having a plurality of unit cell elements formed on a common substrate,
A substrate,
A plurality of unit cell elements electrically isolated and separated in series by a separation groove having a predetermined width on the substrate;
The unit cell element is
A back electrode layer formed on the substrate and provided with a back electrode take-out portion;
A crystalline semiconductor layer that is formed on the surface of the back electrode layer other than the back electrode take-out portion and generates a pn bond by light irradiation;
An optical conversion element cell comprising: a transparent surface electrode layer formed on the crystalline semiconductor layer and provided with a grid electrode.   The crystalline semiconductor layer is composed of a thin film made of a Cu-In-Se based semiconductor material having a chalcopyrite structure containing at least copper (Cu), indium (In), and selenium (Se). Item 4. The optical conversion element cell according to Item 1.   The unit cell element and another unit cell element adjacent to each other with the separation groove interposed therebetween are arranged such that the back surface electrode take-out portions provided in the unit cell element are rotated 180 degrees from each other. The optical conversion element cell according to claim 1 or 2. A plurality of the optical conversion element cells according to any one of claims 1 to 3,
An integrated optical conversion device, wherein a plurality of the optical conversion element cells are integrated by being electrically connected in series. A method of manufacturing an optical conversion element cell having a plurality of unit cell elements on a common substrate,
A thin film laminating step for sequentially laminating a back electrode layer, a crystalline semiconductor layer, and a transparent surface electrode layer on the substrate;
An electrode extraction part forming step of forming a back electrode extraction part in a part of the formed back electrode layer;
A unit cell element separation step of providing a separation groove reaching the substrate from the transparent surface electrode layer laminated on the substrate and forming a plurality of unit cell elements insulated and separated with a predetermined width of the separation groove; ,
And a connecting step of electrically connecting the formed unit cell elements in series with each other.   In the electrode extraction portion forming step, a part of the formed back electrode layer is covered with an adhesion mask, and then the crystalline semiconductor layer and the transparent surface electrode layer are sequentially laminated on the back electrode layer. The method of manufacturing an optical conversion element cell according to claim 5.   The electrode take-out portion forming step removes part of the crystalline semiconductor layer and the transparent surface electrode layer from the back electrode layer, the crystalline semiconductor layer, and the transparent surface electrode layer laminated on the substrate. The method of manufacturing an optical conversion element cell according to claim 5. A method of manufacturing an integrated optical conversion device in which optical conversion element cells are integrated,
A plurality of optical conversion element cells manufactured by the method for manufacturing an optical conversion element cell according to any one of claims 5 to 7 are integrated by being electrically connected in series. A method of manufacturing an integrated optical conversion device.

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