JP2013069761A - Photoelectric conversion device, and manufacturing method of photoelectric conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoelectric conversion device in which it is difficult to exfoliate a lower electrode layer from a substrate.SOLUTION: Such a photoelectric conversion device is adopted that comprises a substrate, and plural photoelectric conversion cells having a conductive layer arranged on the substrate and a photoelectric conversion layer arranged on the conductive layer. In the photoelectric conversion device, the plural photoelectric conversion cells constitute plural cell columns electrically and serially connected to each other in one direction in each column and arranged in line with each other. A separation region for electrically separating one cell column and another cell column is arranged between one cell column and the other cell column adjacent to each other among the plural cell columns, and a coating part for coating a boundary part between the substrate and the conductive layer is arranged in the separation region.

Description

  The present invention relates to a photoelectric conversion device and a method for manufacturing the photoelectric conversion device.

  There is a photoelectric conversion device including a light absorption layer made of a compound semiconductor or the like. In this photoelectric conversion device, for example, a plurality of photoelectric conversion cells are arranged in a plane on a glass substrate.

  Here, in each photoelectric conversion cell, for example, a lower electrode layer made of Mo is arranged on a glass substrate, and a light absorption layer made of a compound semiconductor is arranged on the lower electrode layer. Further, a buffer layer made of zinc sulfide or cadmium sulfide and a transparent upper electrode layer made of zinc oxide or the like are laminated on the light absorption layer in this order.

  In addition, in order to increase the output voltage in the photoelectric conversion device, in the plurality of photoelectric conversion cells, the upper electrode layer of one adjacent photoelectric conversion cell and the lower electrode layer of the other photoelectric conversion cell are connected by a connection conductor. Thus, they are electrically connected in series.

  For such a photoelectric conversion device, a plurality of photoelectric conversion cells are connected in series in one direction to form a cell row, and a plurality of cell rows are arranged at equal intervals in another direction orthogonal to the one direction. A proposed photoelectric conversion device has been proposed (for example, Patent Document 1). In this photoelectric conversion device, a groove portion (also referred to as a groove portion between cell rows) along one direction for electrically separating the cell rows is disposed between adjacent cell rows. And this groove part between cell rows can be formed by scribing by a laser beam, for example.

International Publication No. 2011/090100

  By the way, it is not easy to adjust the output of the laser beam when forming the inter-cell row groove. For example, if the output of the laser light is excessively small, a part of the lower electrode layer remains in the groove portion between the cell rows, and a short circuit is likely to occur between adjacent cell rows. On the other hand, if the output of the laser beam is excessively large, the substrate is also processed, and unnecessary protrusions (also referred to as burrs) are likely to occur near the interface between the substrate and the lower electrode layer.

  If burrs exist in the vicinity of the interface between the substrate and the lower electrode layer, unnecessary stress is likely to be applied near the interface between the substrate and the lower electrode layer when various processes are performed after the formation of the inter-cell row groove. The lower electrode layer is easy to peel from the substrate. For example, when the sealing resin is filled in the inter-cell row groove, unnecessary stress is easily applied to the burrs. Further, when various processes are performed after the formation of the inter-cell row groove portion, the lower electrode layer is disposed on a portion peeled off from the substrate (also referred to as a peeling portion) and a portion in the vicinity of the peeling portion. A defect may occur in the light absorption layer. As a result, the power generation performance of the photoelectric conversion cell can be reduced.

  Further, the photoelectric conversion cell is likely to be deteriorated starting from the peeled portion of the lower electrode layer, and the durability and reliability of the photoelectric conversion device may be lowered.

  Therefore, a photoelectric conversion device in which the lower electrode layer hardly peels from the substrate and a method for manufacturing the same are desired.

  In order to solve the above problem, a photoelectric conversion device according to one embodiment includes a substrate, a conductive layer disposed on the substrate, and a plurality of photoelectric conversion cells including the photoelectric conversion layer disposed on the conductive layer. And. In the photoelectric conversion device, the plurality of photoelectric conversion cells are electrically connected in series in one direction in each column and constitute a plurality of cell columns arranged side by side. Further, in the photoelectric conversion device, a separation region that electrically separates both of the plurality of cell rows is arranged between the adjacent one cell row and the other cell row, and the separation region includes the separation region. A covering portion is disposed to cover a boundary portion between the substrate and the conductive layer.

  A method for manufacturing a photoelectric conversion device according to another aspect includes a step of forming a conductive layer on a substrate, a first separation region that separates the conductive layer in one direction, the first separation region, and the first separation region. Forming a second separation region for separating the conductive layer in another direction different from the one direction, and forming a semiconductor layer on the conductive layer and in the first and second separation regions. doing. And the manufacturing method of this photoelectric conversion apparatus removes the part distribute | arranged in the said 2nd isolation | separation area | region among the said semiconductor layers, The several electrically connected in the said one direction in series Each of the photoelectric conversion cells includes a plurality of cell rows arranged through the second isolation region when viewed in plan, and a part of the semiconductor layer is left in the second isolation region to A step of forming a covering portion covering a boundary portion between the substrate and the conductive layer;

  A method for manufacturing a photoelectric conversion device according to another aspect includes a step of forming a conductive layer on a substrate, a first separation region that separates the conductive layer in one direction, the first separation region, Forming a second separation region that separates the conductive layer in another direction different from the one direction, and forming a covering portion that covers the boundary between the substrate and the conductive layer in the second separation region. And a step of forming a semiconductor layer on the conductive layer and in the first isolation region. And the manufacturing method of this photoelectric conversion apparatus includes a plurality of photoelectric conversion cells electrically connected in series in the one direction by removing the semiconductor layer along the second separation region, And it has the process of forming the several cell row located in a line through the said 2nd separation area | region when planarly viewed.

  According to the photoelectric conversion device according to the above aspect, the lower electrode layer is hardly peeled from the substrate.

  With any of the method for manufacturing a photoelectric conversion device according to another embodiment and the method for manufacturing a photoelectric conversion device according to another embodiment, a photoelectric conversion device in which the lower electrode layer hardly peels from the substrate can be manufactured.

It is a top view which shows typically the structure of the photoelectric conversion apparatus which concerns on one Embodiment. It is a figure which shows the XZ cross section in the position shown with the dashed-dotted line II-II in FIG. It is a figure which shows the YZ cross section in the position shown with the dashed-two dotted line III-III in FIG. It is a figure which shows one structure of the coating | coated part which concerns on one Embodiment. It is a flowchart which shows the manufacturing flow of the photoelectric conversion apparatus which concerns on one Embodiment. It is a figure which shows typically the state in the middle of manufacture of the photoelectric conversion apparatus which concerns on one Embodiment. It is a figure which shows typically the state in the middle of manufacture of the photoelectric conversion apparatus which concerns on one Embodiment. It is a figure which shows typically the state in the middle of manufacture of the photoelectric conversion apparatus which concerns on one Embodiment. It is a figure which shows typically the state in the middle of manufacture of the photoelectric conversion apparatus which concerns on one Embodiment. It is a figure which shows typically the state in the middle of manufacture of the photoelectric conversion apparatus which concerns on one Embodiment. It is a figure which shows typically the state in the middle of manufacture of the photoelectric conversion apparatus which concerns on one Embodiment. It is a figure which shows typically the state in the middle of manufacture of the photoelectric conversion apparatus which concerns on one Embodiment. It is a figure which shows typically the state in the middle of manufacture of the photoelectric conversion apparatus which concerns on one Embodiment. It is a figure which shows typically the state in the middle of manufacture of the photoelectric conversion apparatus which concerns on one Embodiment. It is a figure which shows typically the state in the middle of manufacture of the photoelectric conversion apparatus which concerns on one Embodiment. It is a figure which shows typically the state in the middle of manufacture of the photoelectric conversion apparatus which concerns on one Embodiment. It is a figure which shows one structure of the coating | coated part which concerns on one modification. It is a flowchart which shows the manufacture flow of the photoelectric conversion apparatus which concerns on one modification. It is a figure which shows typically the state in the middle of manufacture of the photoelectric conversion apparatus which concerns on one modification. It is a figure which shows the YZ cross section in the position shown with the dashed-two dotted line XX-XX in FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, parts having the same configuration and function are denoted by the same reference numerals, and redundant description is omitted in the following description. Further, the drawings are schematically shown, and the sizes and positional relationships of various structures in the drawings are not accurately illustrated. 1 to FIG. 4, FIG. 6 to FIG. 17, FIG. 19 and FIG. 20 show the right hand with the X-axis direction as the arrangement direction of the photoelectric conversion cells 10 in each cell row 10g (the left-right direction as viewed in FIG. 1). An XYZ coordinate system of the system is attached.

<(1) Configuration of photoelectric conversion device>
<(1-1) Schematic configuration of photoelectric conversion device>
As shown in FIGS. 1, 2, and 3, the photoelectric conversion device 100 includes a substrate 1 and a plurality of photoelectric conversion cells 10 arranged in a plane on the substrate 1. The plurality of photoelectric conversion cells 10 are arranged in a matrix along the X-axis direction as one direction and the Y-axis direction as the other direction. That is, the plurality of photoelectric conversion cells 10 constitute a column (also referred to as a cell column) 10g of two or more photoelectric conversion cells 10. In each cell row 10g, two or more photoelectric conversion cells 10 are linearly arranged in the X-axis direction as one direction, and the two or more photoelectric conversion cells 10 are electrically connected in series. Has been. A plurality of cell rows 10g are arranged adjacent to each other in the Y-axis direction as the other direction.

  Further, an area for electrically separating the one cell row 10g and the other cell row 10g between one adjacent cell row 10g and the other cell row 10g among the plurality of cell rows 10g. A groove portion P4 is also arranged as (also referred to as a separation region). In other words, of the plurality of cell rows 10g, one adjacent cell row 10g and the other cell row 10g are separated via the groove portion P4. Specifically, the groove portion P4 extends in the X-axis direction between one adjacent cell row 10g and the other cell row 10g. The width of the groove part P4 may be, for example, about 40 μm or more and 1000 μm or less.

  Furthermore, in each cell row 10g, between one photoelectric conversion cell 10 and the other photoelectric conversion cell 10 adjacent to each other among the two or more photoelectric conversion cells 10, the one photoelectric conversion cell 10 and the other photoelectric conversion cell 10 are arranged. A groove portion P3 is provided as a region for separating the conversion cell 10. In other words, the one photoelectric conversion cell 10 and the other photoelectric conversion cell 10 are separated via the groove portion P3. Specifically, the groove portion P3 extends in the Y-axis direction between one adjacent photoelectric conversion cell 10 and the other photoelectric conversion cell 10. The groove portion P3 is arranged from the main surface (also referred to as the upper surface) on the + Z side of the photoelectric conversion cell 10 to the upper surface of the lower electrode layer 2. The width of the groove P3 may be, for example, about 40 μm or more and about 1000 μm or less.

  In addition, when the photoelectric conversion device 100 is modularized, for example, an insulating material such as resin enters the grooves P3 and P4.

  For convenience of illustration, FIG. 1, FIG. 2 and FIG. 3 show one configuration example in which three cell rows 10g and three photoelectric conversion cells 10 are arranged in each cell row 10g. However, the arrangement number of the photoelectric conversion cells 10 is not limited to this. For example, in the photoelectric conversion device 100, two or more cell rows 10g may be arranged, and two or more photoelectric conversion cells 10 may be arranged in each cell row 10g. For example, two or more cell rows 10g may be electrically connected in series or may be connected in parallel.

  The substrate 1 supports a plurality of photoelectric conversion cells 10. As main materials contained in the substrate 1, for example, glass, ceramics, resin, metal and the like can be adopted. In the present embodiment, an example in which the substrate 1 is blue plate glass (soda lime glass) is shown. Moreover, the thickness of the board | substrate 1 should just be about 1 mm or more and 3 mm or less. Furthermore, for example, the shape of the substrate 1 may be a flat plate shape, and the main surface (also referred to as an upper surface) on the + Z side of the substrate 1 may be substantially flat. Note that, for example, a substrate in which an insulating film is coated on a metal substrate may be employed as the substrate 1.

<(1-2) Configuration of photoelectric conversion cell>
Each photoelectric conversion cell 10 includes a lower electrode layer 2, a photoelectric conversion layer 3, an upper electrode layer 4, and a linear conductive portion 5 as conductive layers. Each photoelectric conversion cell 10 is provided with a groove P2. And in the photoelectric conversion apparatus 100 which concerns on this embodiment, the main surface by which the upper electrode layer 4 is distribute | arranged is a light-receiving surface.

  The lower electrode layer 2 is a conductive layer disposed on the upper surface of the substrate 1. As main materials included in the lower electrode layer 2, various conductive metals such as molybdenum, aluminum, titanium, tantalum, and gold can be employed. Moreover, the thickness of the lower electrode layer 2 should just be about 0.2 micrometer or more and about 1 micrometer or less, for example. The lower electrode layer 2 can be formed by, for example, a sputtering method or an evaporation method.

  The lower electrode layer 2 is provided with groove portions P1 and P4. The groove part P1 extends linearly in the Y-axis direction. In FIG. 1, the outer edge of the groove part P1 is indicated by a broken line. Since the one or more grooves P1 are arranged in the lower electrode layer 2, the lower electrode layer 2 is separated into a plurality of lower electrode layers 2 in the X-axis direction. The width of the groove part P1 may be, for example, about 50 μm or more and about 400 μm or less. The groove portion P4 extends linearly in the X-axis direction. Since the one or more grooves P4 are arranged in the lower electrode layer 2, the lower electrode layer 2 is separated into a plurality of regions in the Y-axis direction. That is, the lower electrode layer 2 is provided with one or more grooves P1 and one or more grooves P4, so that the lower electrode layer 2 is separated into a plurality of lower electrode layers 2 in a matrix. 1, 2, and 3 show the lower electrode layer 2 that is separated into three parts in the X-axis direction and the Y-axis direction, respectively.

  By the way, in the photoelectric conversion apparatus 100, the covering portion 20 that covers a boundary portion (also referred to as a boundary portion) 2b between the substrate 1 and the lower electrode layer 2 is disposed in the groove portion P4. With such a configuration, the lower electrode layer 2 is difficult to peel off from the substrate 1. As a result, deterioration of the photoelectric conversion cell 10 starting from the peeling portion of the lower electrode layer 2 from the substrate 1 hardly occurs, and the durability and reliability of the photoelectric conversion device 100 can be improved.

  The photoelectric conversion layer 3 is disposed on the lower electrode layer 2. The photoelectric conversion layer 3 includes a light absorption layer 31 and a buffer layer 32. The light absorption layer 31 and the buffer layer 32 are laminated on the lower electrode layer 2 in this order.

  The light absorption layer 31 is disposed on the main surface (also referred to as the upper surface) on the + Z side of the lower electrode layer 2. Here, in each groove part P <b> 1 arranged in the lower electrode layer 2, an extended portion of the light absorption layer 31 arranged immediately above is embedded. Thereby, in each cell row 10g, one lower electrode layer 2 and the other lower electrode layer 2 which are adjacent to each other via the groove portion P1 are electrically separated.

  The light absorption layer 31 mainly includes a semiconductor having the first conductivity type, and absorbs light to generate an electric charge. Here, as the semiconductor having the first conductivity type, for example, a I-III-VI group compound semiconductor that is a chalcopyrite-based compound semiconductor may be employed. The first conductivity type may be, for example, a p-type conductivity type.

  The I-III-VI group compound semiconductor is a semiconductor mainly containing an I-III-VI group compound. Note that the semiconductor mainly containing the I-III-VI group compound means that the semiconductor contains 70 mol% or more of the I-III-VI group compound. Also in the following description, “mainly included” means “70 mol% or more included”. I-III-VI group compounds mainly consist of group IB elements (also referred to as group 11 elements), group III-B elements (also referred to as group 13 elements), and group VI-B elements (also referred to as group 16 elements). It is a compound contained in.

Examples of the I-III-VI group compound include Cu (In, Ga) Se ₂ (also referred to as CIGS), Cu (In, Ga) (Se, S) ₂ (also referred to as CIGSS), and CuInSe ₂ (also referred to as CIS). Say) can be employed. Note that Cu (In, Ga) Se ₂ is a compound mainly containing Cu, In, Ga, and Se. Cu (In, Ga) (Se, S) ₂ is a compound mainly containing Cu, In, Ga, Se, and S. In the present embodiment, the light absorption layer 31 mainly includes CIGS.

  If the light absorption layer 31 mainly contains an I-III-VI group compound semiconductor, the efficiency of photoelectric conversion by the light absorption layer 31 can be improved even if the thickness of the light absorption layer 31 is 10 μm or less. obtain. For this reason, the thickness of the light absorption layer 31 should just be about 1 micrometer or more and about 3 micrometers or less, for example.

  The light absorption layer 31 can be formed by a vacuum process such as a sputtering method or an evaporation method. The light absorption layer 31 can also be formed by a process called a coating method or a printing method. In the coating method or the printing method, for example, a solution containing a metal element mainly contained in the light absorption layer 31 is applied on the upper surface of the lower electrode layer 2, and then drying and heat treatment are performed. By using a process called a coating method or a printing method, the cost required for manufacturing the photoelectric conversion device 100 can be reduced.

  The buffer layer 32 is disposed on the + Z side main surface (also referred to as an upper surface) of the light absorption layer 31, and mainly includes a semiconductor having a second conductivity type different from the first conductivity type of the light absorption layer 31. . Here, semiconductors having different conductivity types are semiconductors having different conductive carriers. The second conductivity type may be an n-type conductivity type, for example. The conductivity type of the light absorption layer 31 may be n-type, and the conductivity type of the buffer layer 32 may be p-type. Here, a heterojunction region is formed between the light absorption layer 31 and the buffer layer 32. For this reason, in the photoelectric conversion cell 10, photoelectric conversion can occur in the light absorption layer 31 and the buffer layer 32 that form the heterojunction region.

The buffer layer 32 mainly includes a compound semiconductor. Examples of the compound semiconductor included in the buffer layer 32 include CdS, In ₂ S ₃ , ZnS, ZnO, In ₂ Se ₃ , In (OH, S), (Zn, In) (Se, OH), and (Zn, Mg) O or the like can be employed. If the buffer layer 32 has a resistivity of 1 Ω · cm or more, the generation of leakage current can be suppressed.

  The buffer layer 32 may be formed by, for example, a chemical bath deposition (CBD) method. The thickness of the buffer layer 32 may be, for example, 10 nm or more and 200 nm or less. If the thickness of the buffer layer 32 is not less than 100 nm and not more than 200 nm, the buffer layer 32 is unlikely to be damaged when the upper electrode layer 4 is formed on the buffer layer 32 by a sputtering method or the like.

  The upper electrode layer 4 is disposed on the main surface (also referred to as the upper surface) on the + Z side of the photoelectric conversion layer 3. And the upper electrode layer 4 should just be a transparent conductive layer which has an n-type conductivity type, for example. The upper electrode layer 4 serves as an electrode for extracting charges generated in the photoelectric conversion layer 3. The upper electrode layer 4 only needs to mainly contain a material having a lower resistivity than the buffer layer 32. The upper electrode layer 4 may include what is called a window layer, or may include a window layer and a transparent conductive layer.

The upper electrode layer 4 mainly includes a transparent and low resistance material having a wide forbidden band width. As such a material, for example, ZnO, a compound of ZnO, and a metal oxide semiconductor such as ITO and SnO ₂ containing Sn can be adopted. The ZnO compound may be any compound containing any one of Al, B, Ga, In and F, for example.

  The upper electrode layer 4 can be formed by sputtering, vapor deposition, chemical vapor deposition (CVD), or the like. The thickness of the upper electrode layer 4 may be, for example, about 0.1 μm or more and about 2.0 μm or less. Here, if the upper electrode layer 4 has a resistivity of less than 1 Ω · cm and a sheet resistance of 50 Ω / □ or less, electric charges are favorably extracted from the photoelectric conversion layer 3 through the upper electrode layer 4. Can be.

  Here, if the buffer layer 32 and the upper electrode layer 4 have a property of easily transmitting light with respect to the wavelength band of light that can be absorbed by the light absorption layer 31 (also referred to as light transmittance), A decrease in light absorption efficiency in the absorption layer 31 can be suppressed. In addition, when the thickness of the upper electrode layer 4 is 0.05 μm or more and 0.5 μm or less, the light transmittance in the upper electrode layer 4 is enhanced, and the current generated by the photoelectric conversion is improved by the upper electrode layer 4. Can be transmitted. Further, if the absolute refractive index of the upper electrode layer 4 and the absolute refractive index of the buffer layer 32 are substantially the same, the incident light loss caused by the reflection of light at the interface between the upper electrode layer 4 and the buffer layer 32 is reduced. Can be reduced.

  The linear conductive portion 5 is disposed on the main surface (also referred to as the upper surface) on the + Z side of the upper electrode layer 4. The linear conductive portion 5 can be formed by, for example, applying a metal paste on the upper surface of the upper electrode layer 4 and then drying and solidifying the metal paste. The metal paste can be produced, for example, by adding particles having high light reflectivity and conductivity to a binder such as a light-transmitting resin. Here, as the resin having translucency, for example, an epoxy resin or the like may be employed. Moreover, as particles contained in the metal paste, for example, metal particles such as Cu, Al, Ni, and an alloy of Zn and Ag can be adopted. In this case, the linear conductive portion 5 includes a large number of conductive particles, and the large number of particles are in contact with each other, thereby ensuring good conductivity in the linear conductive portion 5. obtain.

  The linear conductive portion 5 includes a plurality of current collecting portions 5a, connecting portions 5b, and hanging portions 5c.

  The plurality of current collectors 5a are separated in the Y-axis direction, and each current collector 5a extends in the X-axis direction. The current collector 5 a plays a role of collecting charges generated in the photoelectric conversion layer 3 and taken out in the upper electrode layer 4. Since the current collector 5a is disposed, the conductivity of the upper electrode layer 4 is supplemented, and thus the upper electrode layer 4 can be thinned. As a result, it is possible to achieve both the securing of charge extraction efficiency and the improvement of light transmittance in the upper electrode layer 4.

  The connecting portion 5b extends in the Y-axis direction. And each current collection part 5a is electrically connected to this connection part 5b. The hanging part 5c is connected to the lower part of the connecting part 5b, and is connected to the lower electrode layer 2 extending from the lower part of the adjacent photoelectric conversion cell 10 arranged in the + X direction through the groove part P2. That is, the connecting part 5b and the lower electrode layer 2 extended from the lower part of the adjacent photoelectric conversion cell 10 can be electrically connected by the hanging part 5c. In addition, the linear conductive part 5 may employ an aspect that does not include the connecting part 5b. As such a linear conductive part 5, for example, there is a mode in which the current collecting part 5 a and the hanging part 5 c are directly electrically connected.

  Here, the groove part P2 extends linearly in the Y-axis direction. The groove portion P <b> 2 is arranged from the upper surface of the upper electrode layer 4 to the upper surface of the lower electrode layer 2. For this reason, the groove part P <b> 2 separates the stacked body in which the photoelectric conversion layer 3 and the upper electrode layer 4 are stacked in one photoelectric conversion cell 10 in the X-axis direction. In addition, the structure by which the drooping part and the drooping part 5c of the upper electrode layer 4 are distribute | arranged in the groove part P2 may be employ | adopted.

  Further, when each photoelectric conversion cell 10 is seen through from above the light receiving surface (here, + Z side), the groove portion P1, the groove portion P2, and the groove portion P3 are arranged in this order in the + X direction. For this reason, the lower electrode layer 2 is disposed between the one photoelectric conversion cell 10 and the other photoelectric conversion cell 10 adjacent to each other in the cell row 10g from the lower part of the other photoelectric conversion cell 10 to the one photoelectric conversion cell. It extends to the lower part of 10. In the one photoelectric conversion cell 10, between the one lower electrode layer 2 and the other lower electrode layer 2 adjacent to each other in the X-axis direction, the groove P1 is passed from above the one lower electrode layer 2. Thus, the photoelectric conversion layer 3 is disposed up to the other lower electrode layer 2. Here, the other lower electrode layer 2 is the lower electrode layer 2 extending from the lower part of the other photoelectric conversion cell 10 to the lower part of the one photoelectric conversion cell 10.

  Further, when each photoelectric conversion cell 10 is seen through from above the light receiving surface (here, + Z side), each photoelectric conversion cell 10 includes a region sandwiched between the groove portion P1 and the groove portion P3 including the groove portion P2. There are a region where the groove portion P1 is disposed and a remaining region. The remaining region is a region contributing to power generation in each photoelectric conversion cell 10.

  In the present embodiment, in each photoelectric conversion cell 10, the photoelectric conversion layer 3 is arranged from above the lower electrode layer 2 to the adjacent lower electrode layer 2, but is not limited thereto. For example, the photoelectric conversion layer 3 should just be distribute | arranged from the upper part of the lower electrode layer 2 to the inside of the groove part P1.

  In the photoelectric conversion cell 10 having the above-described configuration, the adjacent photoelectric conversion in which the charges collected by the upper electrode layer 4 and the plurality of current collecting portions 5a are arranged in the + X direction through the connecting portion 5b and the hanging portion 5c. It is transmitted to the cell 10. Thereby, the adjacent photoelectric conversion cells 10 in each cell row 10g are electrically connected in series.

  In addition, when the width of the current collector 5a is 50 μm or more and 400 μm or less, good conduction between the adjacent photoelectric conversion cells 10 is ensured, and a decrease in the amount of light incident on the light absorption layer 31 is suppressed. obtain. The interval in the Y direction of the plurality of current collectors 5a arranged in one photoelectric conversion cell 10 may be about 2.5 mm, for example.

<(1-3) Covering part in groove part P4>
FIG. 4 schematically shows the configuration of one groove P4 in FIG. 3 and the vicinity thereof. As shown in FIG. 4, the covering portion 20 covers the boundary portion 2 b between the substrate 1 and the lower electrode layer 2 in the groove portion P <b> 4.

  The covering portion 20 includes the same material as that of the photoelectric conversion layer 3. The covering portion 20 can be formed as follows, for example. First, in the lower electrode layer 2, a groove portion P1 as a first separation region and a groove portion P4a as a second separation region corresponding to the groove portion P4 are formed. Next, a stacked body in which the photoelectric conversion layer 3 and the upper electrode layer 4 are stacked in this order is formed on the upper surface of the lower electrode layer 2 in which the groove portions P1 and P4a are formed. At this time, the light absorption layer 31 is also formed in the groove P4a. Then, the part formed in the groove part P4a of this laminated body and on the groove part P4a is mechanically shaved. At this time, part of the light absorption layer 31 included in the laminate remains, so that the covering portion 20 can be formed. At this time, the covering portion 20 may mainly include the same material as that of the light absorption layer 31. When such a configuration is employed, the covering portion 20 can be easily formed.

<(2) Manufacturing process of photoelectric conversion device>
Here, an example of a manufacturing process of the photoelectric conversion device 100 having the above configuration will be described. FIG. 5 is a flowchart illustrating the manufacturing flow of the photoelectric conversion apparatus 100. FIGS. 6 to 9 and FIGS. 11 to 16 are cross-sectional views schematically showing a state in the process of manufacturing the photoelectric conversion device 100. 8 is a diagram showing an XZ cross section at the position indicated by the one-dot chain line VIII-VIII in FIG. 9 is a diagram showing a YZ cross section at the position indicated by the two-dot chain line IX-IX in FIG.

  First, in step Sp1 of FIG. 5, the substrate 1 (see FIG. 6) is prepared. The substrate 1 may be, for example, a flat plate having a substantially rectangular board surface.

  In step Sp2, the lower electrode layer 2 (see FIG. 7) as a conductive layer is formed on the substrate 1. The lower electrode layer 2 can be formed, for example, on substantially the entire main surface of the cleaned substrate 1 by using a sputtering method or a vapor deposition method.

  In step Sp3, as a first separation region extending linearly in the other direction (here, the Y-axis direction) from a predetermined formation target position on the upper surface of the lower electrode layer 2 to the upper surface of the substrate 1 immediately below it. Groove P1 (see FIGS. 8 and 10) is formed. Further, a groove portion P4a serving as a second separation region extending linearly in one direction (here, the X-axis direction) from a predetermined formation target position on the upper surface of the lower electrode layer 2 to the upper surface of the substrate 1 immediately below the formation position. (See FIGS. 9 and 10). The groove portion P4a is formed at a position corresponding to the groove portion P4. That is, a groove P1 that separates the lower electrode layer 2 in the X-axis direction as one direction, and a groove P4a that intersects the groove P1 and separates the lower electrode layer 2 in the Y-axis direction as another direction different from the one direction. And are formed. The grooves P1 and P4a can be formed, for example, by irradiating a predetermined formation target position while scanning with a YAG laser or other laser light.

  In Step Sp4, a film 310 (see FIGS. 11 and 12) containing the metal element mainly contained in the light absorption layer 31 is formed on the lower electrode layer 2. The film 310 can be formed, for example, by performing a process of drying after a solution containing a metal element mainly contained in the light absorption layer 31 is applied on the lower electrode layer 2. At this time, the film 310 is also formed in the groove portions P1 and P4a and on the groove portions P1 and P4a.

  In step Sp5, the heat treatment is performed on the film 310, whereby the crystallization of the compound semiconductor in the film 310 proceeds, and the light absorption layer 31 (see FIGS. 11 and 12) is formed. At this time, the light absorption layer 31 is also formed in the groove portions P1 and P4a and on the groove portions P1 and P4a. That is, the light absorption layer 31 as a semiconductor layer is formed on the lower electrode layer 2 and in the grooves P1 and P4a.

  In Step Sp6, the buffer layer 32 (see FIG. 13) is formed on the light absorption layer 31. Thereby, the photoelectric conversion layer 3 in which the light absorption layer 31 and the buffer layer 32 are laminated is formed. The buffer layer 32 may be formed by, for example, a chemical bath deposition (CBD) method. Specifically, for example, the buffer layer 32 mainly containing CdS can be formed by immersing the light absorption layer 31 in a solution prepared by dissolving cadmium acetate and thiourea in ammonia.

  In Step Sp7, the upper electrode layer 4 (see FIG. 14) is formed on the photoelectric conversion layer 3. Thereby, the laminated body of the photoelectric converting layer 3 and the upper electrode layer 4 is formed over the groove part P4a from the inside of the groove part P4a. The upper electrode layer 4 can be formed by, for example, a sputtering method, a vapor deposition method, a chemical vapor deposition (CVD) method, or the like. Specifically, for example, the transparent upper electrode layer 4 mainly including ZnO to which Al is added is formed on the buffer layer 32.

  In step Sp8, a groove portion P2 extending linearly in one direction (here, the Y-axis direction) in a region from a predetermined formation target position on the upper surface of the upper electrode layer 4 to the upper surface of the lower electrode layer 2 (FIG. 15) is formed. The groove part P2 can be formed by mechanical scribing using a scribe needle.

  In step Sp9, the linear conductive portion 5 (see FIG. 16) is formed from a predetermined formation target position on the upper surface of the upper electrode layer 4 to the inside of the groove portion P2. The linear conductive part 5 can be formed by, for example, printing so that the metal paste has a predetermined pattern, and solidifying the printed metal paste by drying.

  In step Sp10, a groove portion P3 (see FIG. 5) extending linearly in one direction (here, the Y-axis direction) in a region extending from a predetermined formation target position of the upper surface of the upper electrode layer 4 to the upper surface of the lower electrode layer 2. 1 and FIG. 2) is formed.

  In Step Sp11, the stacked portion of the photoelectric conversion layer 3 and the upper electrode layer 4 formed from the inside of the groove P4a to the groove P4a in Steps Sp4 to Sp7 is removed, so that the groove P4 (see FIGS. 1 and 3). Is formed. Thereby, the photoelectric conversion apparatus 100 can be formed. In Step Sp11, the groove portion P4 can be formed by mechanical scribing using a scribe needle or the like. At this time, a portion of the light absorption layer 31 formed in Step Sp5 that is disposed in the groove P4a is removed. Thereby, a plurality of cell rows 10g (see FIG. 1) arranged via the groove portion P4 including the groove portion P4a are formed. From another viewpoint, when the photoelectric conversion device 100 is viewed in plan from the upper electrode layer 4 side, a plurality of cell rows 10g are arranged via the groove portion P4a. Each cell row 10g includes a plurality of photoelectric conversion cells 10 electrically connected in series in the X-axis direction as one direction. At this time, a part of the light absorption layer 31 is left in the groove P4a, so that the covering portion 20 (see FIGS. 1 and 3) covering the boundary portion 2b between the substrate 1 and the lower electrode layer 2 is formed. The

<(3) Summary of one embodiment>
As described above, in the photoelectric conversion device 100 according to the present embodiment, the covering portion 20 that covers the boundary portion 2b between the substrate 1 and the lower electrode layer 2 is disposed in the groove portion P4. Thereby, the lower electrode layer 2 is difficult to peel from the substrate 1. As a result, deterioration of the photoelectric conversion cell 10 starting from the portion where the lower electrode layer 2 is peeled off from the substrate 1 hardly occurs, and the durability and reliability of the photoelectric conversion device 100 can be ensured. Moreover, the coating | coated part 20 can be easily formed because the coating | coated part 20 contains the same material as the light absorption layer 31 contained in the photoelectric converting layer 3. FIG.

  In the manufacturing process of the photoelectric conversion device 100, the photoelectric conversion layer 3 is formed on the lower electrode layer 2 after the groove P <b> 4 a is formed in the lower electrode layer 2. Thereafter, portions of the photoelectric conversion layer 3 arranged in the groove portion P4a and on the groove portion P4a are removed to form a plurality of cell rows 10g. At this time, by leaving a part of the light absorption layer 31 in the groove portion P4a, the covering portion 20 that covers the boundary portion 2b between the substrate 1 and the lower electrode layer 2 is formed. By such a manufacturing method, the photoelectric conversion device 100 in which the lower electrode layer 2 is hardly peeled off from the substrate 1 can be formed.

<(4) Modification>
The present invention is not limited to the above-described embodiment, and various modifications and improvements can be made without departing from the spirit of the present invention.

  For example, in the above-described embodiment, the covering portion 20 is mainly composed of the same material as the light absorption layer 31, but is not limited thereto. For example, as shown in FIG. 17, the covering portion 20 may be further covered with an upper covering portion 21. When this configuration is adopted, for example, the upper covering portion 21 that covers the covering portion 20 may be formed after the covering portion 20 is formed by the same manufacturing method as in the above embodiment. As a material of the upper cover portion 21, various waterproof resins such as a silicone resin and a polyimide resin can be employed, for example. Moreover, the upper coating | coated part 21 can be formed by application | coating and drying of resin, etc., for example. The linear expansion coefficient of the silicone resin is 200 to 300 ppm / ° C., and the linear expansion coefficient of the polyimide resin is 30 to 50 ppm / ° C.

  In the above-described embodiment, the covering portion 20 mainly includes a semiconductor, but is not limited thereto. For example, the material included in the covering portion 20 may be a material having either an insulating property or a conductive property. Here, as the material having insulating properties, various resins such as a silicone resin and a polyimide resin can be employed. In this case, for example, the resin may be applied so as to cover the boundary portion 2b between the substrate 1 and the lower electrode layer 2 in the groove portion P4 or the groove portion P4a. Various metals can be used as the conductive material. In this case, for example, a metal may be deposited so as to cover the boundary portion 2b between the substrate 1 and the lower electrode layer 2 in the groove portion P4 or the groove portion P4a. At this time, if an insulator is disposed in the groove P4 or in the groove P4a, a short circuit is unlikely to occur between the lower electrode layers 2 adjacent to each other with the groove P4 interposed therebetween.

  Further, if the covering portion 20 has a low moisture permeability, that is, has a waterproof property, the photoelectric conversion cell is less likely to be deteriorated starting from the portion where the lower electrode layer 2 is peeled off from the substrate 1. The durability and reliability of the device 100 can be further improved.

  Here, when the solar cell module using the photoelectric conversion device 100 is manufactured, the groove P4 may be filled with a sealing resin such as ethylene vinyl acetate copolymer resin (EVA). For this reason, as a material of the coating | coated part 20 which has waterproofness, resin which has a linear expansion coefficient close | similar to the linear expansion coefficient of resin for sealing can be employ | adopted, for example. The linear expansion coefficient of EVA is 140 ppm / ° C. And as resin which has a linear expansion coefficient close | similar to the linear expansion coefficient of EVA, resin, such as polyethylene and a polypropylene, can be employ | adopted. The linear expansion coefficient of polyethylene is 130 ppm / ° C., and the linear expansion coefficient of polypropylene is 110 ppm / ° C.

  A material having a linear expansion coefficient in the vicinity of the intermediate between the linear expansion coefficient of the substrate 1 and the linear expansion coefficient of the sealing resin may be adopted as the material of the waterproof covering portion 20. For example, when soda lime glass having a linear expansion coefficient of 9 ppm / ° C. is the material of the substrate 1, vinyl chloride having a linear expansion coefficient of 70 ppm / ° C. can be adopted as the material of the covering portion 20 having waterproofness.

  In the embodiment described above, the groove portion P2 is formed after the upper electrode layer 4 is formed. However, the present invention is not limited to this. For example, the upper electrode layer 4 may be formed after the formation of the groove portion P2. However, the electrical resistance in electrical connection between the adjacent photoelectric conversion cells 10 in each cell row 10g can be reduced when the groove portion P2 is formed after the formation of the upper electrode layer 4.

  In the embodiment described above, the covering portion 20 is formed by leaving a part of the light absorption layer 31 in the groove portion P4a. However, the present invention is not limited to this. For example, the covering portion 20 may be formed after the formation of the groove portion P4a and before the formation of the light absorption layer 31. Hereinafter, a method for forming the covering portion 20 will be described with specific examples.

  FIG. 18 is a flowchart illustrating the manufacturing flow of the photoelectric conversion apparatus 100A according to a modification. 19 and 20 are diagrams schematically illustrating a state in the middle of manufacturing the photoelectric conversion device 100A according to the modification.

  First, in steps Sp21 to Sp23 in FIG. 18, the same processes as those in steps Sp1 to Sp3 in FIG. 5 are sequentially performed. At this time, a lower electrode layer 2 is formed on the substrate 1, a groove part P1 that separates the lower electrode layer 2 in the X-axis direction as one direction, and intersects the groove part P1 and has the lower electrode layer 2 in one direction. Is formed with a groove P4a separating in the Y-axis direction as a different other direction.

  Next, in step Sp24, in the groove P4a (see FIGS. 9 and 10) formed in step Sp23, a covering portion 20 (see FIGS. 19 and 20) that covers the boundary 2b between the substrate 1 and the lower electrode layer 2 is used. Is formed. Here, for example, the covering portion 20 can be formed by a sol-gel method using a glass material. As a material of the covering portion 20, glass such as silica can be adopted.

  In steps Sp25 to Sp31, processes similar to those in steps Sp4 to Sp10 in FIG. 5 are performed in order. At this time, the light absorption layer 31 as a semiconductor layer is formed on the lower electrode layer 2 and in the groove P4a.

  In step Sp32, the stacked portion of the photoelectric conversion layer 3 and the upper electrode layer 4 formed from the groove portion P4a to the groove portion P4a in steps Sp25 to Sp28 is removed along the groove portion P4a, thereby forming the groove portion P4. Is done. Thereby, the photoelectric conversion device 100A can be formed. Here, the groove portion P4 can be formed by mechanical scribing using a scribe needle or the like. At this time, the light absorption layer 31 is removed along the groove P4a, whereby a plurality of cell rows 10g are formed. And the coating | coated part 20 formed by step Sp24 remains in the groove part P4. The plurality of cell rows 10g are arranged via the groove portion P4 including the groove portion P4a. From another viewpoint, when the photoelectric conversion device 100A is viewed in plan from the upper electrode layer 4 side, a plurality of cell rows 10g are arranged via the groove portion P4a. Each cell row 10g includes a plurality of photoelectric conversion cells 10 electrically connected in series in the X-axis direction as one direction.

  It goes without saying that all or a part of each of the above-described embodiment and various modifications can be appropriately combined within a consistent range.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Lower electrode layer 2b Boundary part 3 Photoelectric conversion layer 4 Upper electrode layer 5 Linear conductive part 10 Photoelectric conversion cell 10g Cell array 20 Covering part 21 Upper cover part 31 Light absorption layer 32 Buffer layer 100, 100A Photoelectric conversion device P1 , P2, P3, P4, P4a Groove

Claims (6)

A substrate,
A plurality of photoelectric conversion cells having a conductive layer disposed on the substrate and a photoelectric conversion layer disposed on the conductive layer;
The plurality of photoelectric conversion cells are electrically connected in series in one direction in each row and constitute a plurality of cell rows arranged side by side,
A separation region that electrically separates both of the plurality of cell rows is disposed between one of the adjacent cell rows and the other cell row,
A photoelectric conversion device in which a covering portion that covers a boundary portion between the substrate and the conductive layer is disposed in the separation region.   The photoelectric conversion device according to claim 1, wherein the covering portion includes the same material as the photoelectric conversion layer.   The photoelectric conversion device according to claim 1, wherein the covering portion is waterproof. Forming a conductive layer on the substrate;
Forming a first separation region that separates the conductive layer in one direction, and a second separation region that intersects the first separation region and separates the conductive layer in another direction different from the one direction;
Forming a semiconductor layer on the conductive layer and in the first and second isolation regions;
Each of the semiconductor layers includes a plurality of photoelectric conversion cells electrically connected in series in the one direction by removing a portion disposed in the second isolation region, and is viewed in plan Sometimes, a plurality of cell rows are formed side by side through the second isolation region, and a part of the semiconductor layer is left in the second isolation region to cover the boundary between the substrate and the conductive layer. And a step of forming a covering portion.   The method for manufacturing a photoelectric conversion device according to claim 4, further comprising a step of forming an upper covering portion that covers the covering portion after the step of forming the covering portion. Forming a conductive layer on the substrate;
Forming a first separation region that separates the conductive layer in one direction, and a second separation region that intersects the first separation region and separates the conductive layer in another direction different from the one direction;
Forming a covering portion that covers a boundary portion between the substrate and the conductive layer in the second separation region;
Forming a semiconductor layer on the conductive layer as well as in the first isolation region;
By removing the semiconductor layer along the second isolation region, each of the second isolation regions includes a plurality of photoelectric conversion cells electrically connected in series in the one direction, and when viewed in plan. And a step of forming a plurality of cell rows arranged through the region.

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