JP6489785B2 - Photoelectric conversion element and method for producing photoelectric conversion element - Google Patents

Description

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

  In recent years, a solar cell that directly converts solar energy into electric energy has been rapidly expected as a next-generation energy source particularly from the viewpoint of global environmental problems. There are various types of solar cells, such as those using compound semiconductors or organic materials, but the mainstream is currently using silicon crystals.

  Currently, the most manufactured and sold solar cells have a structure in which electrodes are respectively formed on a light receiving surface that is a surface on which sunlight is incident and a back surface that is opposite to the light receiving surface.

  However, when an electrode is formed on the light receiving surface, sunlight is reflected and absorbed by the electrode, so that the amount of incident sunlight is reduced by the area of the electrode. For this reason, development of solar cells in which electrodes are formed only on the back surface has been underway.

  For example, in Patent Document 1, a finger electrode of a p-side electrode on a linear portion of a p-type semiconductor layer on the back surface of a semiconductor substrate and a finger of an n-side electrode on a linear portion of an n-type semiconductor layer on the back surface of the semiconductor substrate are disclosed. A back junction solar cell is disclosed in which electrodes are formed so as to extend along a direction parallel to a direction in which linear grooves (saw marks) on the back surface of a semiconductor substrate extend.

  In the solar cell described in Patent Document 1, by forming the finger electrode of the p-side electrode and the finger electrode of the n-side electrode in a direction parallel to the extending direction of the linear groove, the linear portion of the p-type semiconductor layer is formed. Since the direction in which the etching agent used for forming the linear portion of the n-type semiconductor layer spreads and the direction in which the linear groove extends are parallel to each other, the etching agent is less likely to wet and spread in the width direction of the linear portion. It is said that the linear portion of the semiconductor layer and the linear portion of the n-type semiconductor layer can be formed with high formation accuracy.

JP 2012-49183 A

  However, the solar cell described in Patent Document 1 has a problem that the finger electrode of the p-side electrode and the finger electrode of the n-side electrode are easily peeled off.

  An embodiment disclosed herein includes a semiconductor substrate of a first conductivity type or a second conductivity type, a first conductivity type portion and a second conductivity type portion provided on one side of the semiconductor substrate, and a first conductivity type. A first electrode on the portion and a second electrode on the second conductivity type portion, the first electrode and the second electrode extending in a direction forming an angle of 90 ° ± 5 ° with the side of the semiconductor substrate. The semiconductor substrate is a photoelectric conversion element including a linear groove extending in a direction that forms an angle of 90 ° ± 5 ° with the first electrode and the second electrode.

  The embodiment disclosed herein includes a step of cutting a semiconductor crystal with a wire saw to form a semiconductor substrate of a first conductivity type or a second conductivity type, a first conductivity type portion and a second conductivity type on one side of the semiconductor substrate. Forming a first electrode by a step of forming a conductive type portion, a step of forming a first electrode on the first conductive type portion, and a step of forming a second electrode on the second conductive type portion. In the step and the step of forming the second electrode, the first electrode and the second electrode respectively extend in a direction that forms an angle of 90 ° ± 5 ° with the side of the semiconductor substrate, and the semiconductor substrate This is a method for manufacturing a photoelectric conversion element formed so as to include a linear groove extending in a direction forming an angle of 90 ° ± 5 ° with the second electrode.

  According to the embodiment disclosed herein, it is possible to suppress the peeling of the electrode as compared with the conventional case.

2 is a schematic cross-sectional view of a heterojunction back contact cell according to Embodiment 1. FIG. (A) is a typical top view of the back surface of a heterojunction type back contact cell, (b) is the relationship between the extending direction of a 1st electrode and a 2nd electrode, and the length direction of the side of the back surface of a semiconductor substrate. FIG. (A) is a typical top view of the back surface of the semiconductor substrate of a heterojunction type back contact cell, (b) is a figure illustrating the relationship between the extending direction of a 1st electrode and a 2nd electrode, and a linear groove | channel. It is. It is a typical perspective view illustrating an example of the process of cutting an n-type silicon single crystal ingot with a wire saw. It is a typical perspective view illustrating an example of a process in which a semiconductor substrate which is an n-type single crystal silicon substrate is formed from an n-type silicon single crystal ingot. It is typical sectional drawing of an example of the wire saw shown in FIG. 10 is a schematic cross-sectional view illustrating an example of a step of forming a first i-type amorphous semiconductor film over the entire back surface of a semiconductor substrate. FIG. It is typical sectional drawing illustrating an example of the process of forming the 1st conductivity type amorphous semiconductor film on the 1st i type amorphous semiconductor film. It is typical sectional drawing illustrating an example of the process of forming an etching mask on the 1st conductivity type amorphous semiconductor film. It is typical sectional drawing illustrating an example of the process of etching a part of laminated body of a 1st i-type amorphous semiconductor film and a 1st conductivity type amorphous semiconductor film in the thickness direction. It is typical sectional drawing illustrating an example of the process of removing an etching mask. It is typical sectional drawing illustrating an example of the process of forming the 2nd i-type amorphous semiconductor film. It is typical sectional drawing illustrating an example of the process of forming a 2nd conductivity type amorphous semiconductor film on the 2nd i-type amorphous semiconductor film. It is typical sectional drawing illustrating an example of the process of forming an etching mask only in the part which leaves the laminated body of a 2nd i-type amorphous semiconductor film and a 2nd conductivity type amorphous semiconductor film. It is typical sectional drawing illustrating an example of the process of exposing a part of 1st conductivity type amorphous semiconductor film. It is a typical expanded sectional view of an example of the back of the heterojunction type back contact cell of Embodiment 1 along the extension direction of the 1st electrode and the 2nd electrode. It is a typical expanded sectional view of the other example of the back surface of the heterojunction type back contact cell of Embodiment 1 along the extension direction of the 1st electrode and the 2nd electrode. 6 is a schematic plan view of the back surface of the heterojunction back contact cell of Embodiment 2. FIG. It is a figure illustrating an example of the process of cut | disconnecting the n-type silicon single crystal ingot of Embodiment 3 using a loose abrasive and a wire saw. 6 is a schematic cross-sectional view of a back electrode type solar battery cell of Embodiment 4. FIG. 10 is a schematic cross-sectional view illustrating a part of the manufacturing process of an example of the manufacturing method of the back electrode type solar battery cell of Embodiment 4. FIG. 10 is a schematic cross-sectional view illustrating a part of the manufacturing process of an example of the manufacturing method of the back electrode type solar battery cell of Embodiment 4. FIG. 10 is a schematic cross-sectional view illustrating a part of the manufacturing process of an example of the manufacturing method of the back electrode type solar battery cell of Embodiment 4. FIG. 10 is a schematic cross-sectional view illustrating a part of the manufacturing process of an example of the manufacturing method of the back electrode type solar battery cell of Embodiment 4. FIG. 10 is a schematic cross-sectional view illustrating a part of the manufacturing process of an example of the manufacturing method of the back electrode type solar battery cell of Embodiment 4. FIG. 10 is a schematic cross-sectional view illustrating a part of the manufacturing process of an example of the manufacturing method of the back electrode type solar battery cell of Embodiment 4. FIG. 10 is a schematic cross-sectional view illustrating a part of the manufacturing process of an example of the manufacturing method of the back electrode type solar battery cell of Embodiment 4. FIG. 10 is a schematic cross-sectional view illustrating a part of the manufacturing process of an example of the manufacturing method of the back electrode type solar battery cell of Embodiment 4. FIG. 10 is a schematic cross-sectional view illustrating a part of the manufacturing process of an example of the manufacturing method of the back electrode type solar battery cell of Embodiment 4. FIG.

  Hereinafter, embodiments will be described. In the drawings used to describe the embodiments, the same reference numerals represent the same or corresponding parts.

[Embodiment 1]
<Structure>
FIG. 1 is a schematic cross-sectional view of a heterojunction back contact cell of Embodiment 1 which is an example of the photoelectric conversion element of the embodiment. The heterojunction back contact cell 10 according to the first embodiment is arranged on the back surface of the semiconductor substrate 1 so as to be adjacent to the semiconductor substrate 1 which is an n-type single crystal silicon substrate and the front surface (back surface) on one side of the semiconductor substrate 1. A first i-type amorphous semiconductor film 2 and a second i-type amorphous semiconductor film 4 provided in contact with each other are provided. In the first embodiment, each of the first i-type amorphous semiconductor film 2 and the second i-type amorphous semiconductor film 4 is an i-type amorphous silicon film.

  On the first i-type amorphous semiconductor film 2, a first conductive amorphous semiconductor film 3 in contact with the first i-type amorphous semiconductor film 2 is provided. On the second i-type amorphous semiconductor film 4, a second conductivity-type amorphous semiconductor film 5 in contact with the second i-type amorphous semiconductor film 4 is provided. In the first embodiment, the first conductive amorphous semiconductor film 3 is a p-type amorphous silicon film, and the second conductive amorphous semiconductor film 5 is an n-type amorphous silicon film.

  A first electrode 11 in contact with the first conductive type amorphous semiconductor film 3 is provided on the first conductive type amorphous semiconductor film 3. A second electrode 12 in contact with the second conductive type amorphous semiconductor film 5 is provided on the second conductive type amorphous semiconductor film 5.

  Then, both end portions of the stacked body of the second i-type amorphous semiconductor film 4 and the second conductive type amorphous semiconductor film 5 are respectively connected to the first i-type amorphous semiconductor film 2 and the first conductive type. The edge part of the laminated body with the type amorphous semiconductor film 3 is covered. Therefore, the end of the second i-type amorphous semiconductor film 4 is located between the first conductive type amorphous semiconductor film 3 and the second conductive type amorphous semiconductor film 5, and the second Both ends of the i-type amorphous semiconductor film 4 are in contact with both the first conductive type amorphous semiconductor film 3 and the second conductive type amorphous semiconductor film 5. As a result, the first conductive amorphous semiconductor film 3 and the second conductive amorphous semiconductor film 5 are separated by the second i-type amorphous semiconductor film 4.

  FIG. 2A shows a schematic plan view of the back surface of the heterojunction back contact cell 10. As shown in FIG. 2A, the first electrodes 11 and the second electrodes 12 are alternately arranged on the back surface of the heterojunction back contact cell 10 with a space therebetween. Each of the two electrodes 12 extends linearly between a pair of sides 1a and 1b facing each other on the back surface of the octagonal semiconductor substrate 1 so that the longitudinal directions of these electrodes are the same. ing.

  Here, as shown in FIG. 2B, the first electrode 11 and the second electrode 12 are arranged such that the extending direction 21 of the first electrode 11 and the second electrode 12 is the side 1 a (or side) on the back surface of the semiconductor substrate 1. It is positioned so as to be included in a range 23 in a direction that makes an angle of 90 ° ± 5 ° with the length direction 22 of 1b).

  FIG. 3A is a schematic plan view of the back surface of the semiconductor substrate 1 of the heterojunction back contact cell 10. As shown in FIG. 3A, the linear groove 6 exists on the back surface of the semiconductor substrate 1. The linear groove 6 is formed by, for example, damaging the back surface of the semiconductor substrate 1 when the semiconductor substrate 1 is produced by cutting the semiconductor crystal ingot using a wire saw and abrasive grains, as will be described later. Although it may be formed abrasive grain marks (saw marks), the linear grooves 6 are not limited to saw marks, and may be linear grooves other than saw marks.

  In the present embodiment, the linear groove 6 is linear. In the present embodiment, the length of the linear groove 6 is longer than 3 cm, and the depth of the linear groove 6 is not less than 3 μm and not more than 4 μm. The length of the linear groove 6 means the length from the start point to the end point of each linear groove 6 extending on the back surface of the semiconductor substrate 1.

  Here, as shown in FIG. 3 (b), the linear groove 6 has an extending direction 24 of the linear groove 6 that is 90 ° ± 5 ° to the extending direction 21 of the first electrode 11 and the second electrode 12. It is positioned so as to be included in the range 25 of the direction that forms the angle.

<Manufacturing method>
Hereinafter, an example of a method for manufacturing the heterojunction back contact cell of Embodiment 1 will be described with reference to FIGS. First, as shown in the schematic perspective view of FIG. 4, a step of cutting the n-type silicon single crystal ingot 30 with a wire saw 33 is performed.

  As shown in FIG. 4, the wire saw 33 is wound around guide rollers 31 and 32 arranged at a predetermined interval. As a result, the wire saw 33 is stretched at a plurality of locations at predetermined intervals along the longitudinal direction of the guide rollers 31 and 32 in the respective guide rollers 31 and 32. In this state, when the guide rollers 31 and 32 repeat normal rotation and reverse rotation, the wire saw 33 reciprocates in the direction of the arrow 35.

  The n-type silicon single crystal ingot 30 is moved in the direction of the arrow 34 while the wire saw 33 is reciprocating in the direction of the arrow 35. Then, by pressing the n-type silicon single crystal ingot 30 against the wire saw 33 that reciprocates, the n-type silicon single crystal ingot 30 is cut at a plurality of locations, as shown in the schematic perspective view of FIG. The semiconductor substrate 1 which is a plurality of plate-like n-type single crystal silicon substrates is formed. At this time, a linear groove 6 that is a saw mark can be formed on the back surface of the semiconductor substrate 1 by the fixed abrasive grains damaging the back surface of the semiconductor substrate 1. This is presumably due to the bending of the wire saw 33 when the n-type silicon single crystal ingot 30 is cut. However, as described above, the linear groove 6 is not limited to the saw mark.

  FIG. 6 shows a schematic cross-sectional view of an example of the wire saw 33 shown in FIG. Here, the wire saw 33 includes a core wire 33a and fixed abrasive grains 33b fixed to the outer peripheral surface of the core wire 33a with a bonding material (not shown). For example, a piano wire can be used as the core wire 33a. As the fixed abrasive grains 33b, for example, diamond abrasive grains can be used, and as the bonding material, for example, nickel plated on the outer surface of the core wire 33a can be used.

  As the n-type silicon single crystal ingot 30, for example, an n-type single crystal silicon ingot produced by the Czochralski method can be used.

  Next, as shown in the schematic cross-sectional view of FIG. 7, a first i-type amorphous semiconductor film 2 is formed on the entire back surface of the semiconductor substrate 1. The method for forming the first i-type amorphous semiconductor film 2 is not particularly limited. For example, a plasma CVD (Chemical Vapor Deposition) method can be used.

  As the semiconductor substrate 1, an n-type single crystal silicon substrate can be suitably used, but is not limited to an n-type single crystal silicon substrate, and for example, a conventionally known n-type semiconductor substrate can be used as appropriate.

  As the first i-type amorphous semiconductor film 2, an i-type amorphous silicon film can be preferably used, but is not limited to an i-type amorphous silicon film. A quality semiconductor film can also be used.

In the present specification, “i-type” means not only a completely intrinsic state but also a sufficiently low concentration (the n-type impurity concentration is less than 1 × 10 ¹⁵ / cm ³ and the p-type impurity concentration is 1 × (Less than 10 ¹⁵ / cm ³ ) is meant to include n-type or p-type impurities.

  In this specification, “amorphous silicon” includes not only amorphous silicon in which dangling bonds of silicon atoms are not terminated with hydrogen, but also silicon such as hydrogenated amorphous silicon. Also included are those in which dangling bonds of atoms are terminated with hydrogen.

  Next, as shown in the schematic cross-sectional view of FIG. 8, a first conductivity type amorphous semiconductor film 3 is formed on the first i-type amorphous semiconductor film 2. Although the formation method of the 1st conductivity type amorphous semiconductor film 3 is not specifically limited, For example, plasma CVD method can be used.

  As the first conductive type amorphous semiconductor film 3, a p-type amorphous silicon film can be preferably used. However, the first conductive type amorphous semiconductor film 3 is not limited to a p-type amorphous silicon film. A semiconductor film can also be used.

As the p-type impurity contained in the first conductive type amorphous semiconductor film 3, for example, boron can be used. In this specification, “p-type” means a state where the p-type impurity concentration is 1 × 10 ¹⁵ / cm ³ or more.

  Next, as shown in the schematic cross-sectional view of FIG. 9, the first i-type amorphous semiconductor film 2 and the first conductivity-type amorphous semiconductor film 3 are formed on the first conductivity-type amorphous semiconductor film 3. An etching mask 41 such as a photoresist having an opening at a location where the stacked body is etched in the thickness direction is formed.

  Next, as shown in the schematic cross-sectional view of FIG. 10, using the etching mask 41 as a mask, one layered body of the first i-type amorphous semiconductor film 2 and the first conductive type amorphous semiconductor film 3 is formed. The part is etched in the thickness direction. Thereby, a part of the back surface of the semiconductor substrate 1 is exposed. Thereafter, as shown in the schematic cross-sectional view of FIG. 11, all the etching mask 41 is removed.

  Next, as shown in the schematic sectional view of FIG. 12, the semiconductor substrate 1 and the stacked body of the first i-type amorphous semiconductor film 2 and the first conductive amorphous semiconductor film 3 are covered. A second i-type amorphous semiconductor film 4 is formed. The method for forming the second i-type amorphous semiconductor film 4 is not particularly limited, and for example, a plasma CVD method can be used.

  As the second i-type amorphous semiconductor film 4, an i-type amorphous silicon film can be suitably used, but is not limited to an i-type amorphous silicon film. For example, a conventionally known i-type amorphous silicon film is used. A quality semiconductor film can also be used.

  Next, as shown in the schematic cross-sectional view of FIG. 13, a second conductivity type amorphous semiconductor film 5 is formed on the second i-type amorphous semiconductor film 4. Although the formation method of the 2nd conductivity type amorphous semiconductor film 5 is not specifically limited, For example, plasma CVD method can be used.

  As the second conductive type amorphous semiconductor film 5, an n-type amorphous silicon film can be preferably used, but is not limited to an n-type amorphous silicon film. For example, a conventionally known n-type amorphous silicon film is used. A semiconductor film can also be used.

As the n-type impurity contained in the n-type amorphous silicon film constituting the second conductivity type amorphous semiconductor film 5, for example, phosphorus can be used. In this specification, “n-type” means a state where the n-type impurity concentration is 1 × 10 ¹⁵ / cm ³ or more.

  Next, as shown in the schematic cross-sectional view of FIG. 14, a stacked body of the second i-type amorphous semiconductor film 4 and the second conductive amorphous semiconductor film 5 on the back surface of the semiconductor substrate 1 is left. An etching mask 42 such as a photoresist is formed only on the portion.

  Next, using the etching mask 42 as a mask, a part of the stacked body of the second i-type amorphous semiconductor film 4 and the second conductive amorphous semiconductor film 5 is wet-etched in the thickness direction, As shown in the schematic cross-sectional view of FIG. 15, a part of the first conductive type amorphous semiconductor film 3 is exposed. Thereafter, the etching mask 42 is completely removed.

  Thereafter, as shown in FIGS. 1 and 2, the first electrode 11 is formed so as to be in contact with the first conductive type amorphous semiconductor film 3, and the second electrode is formed so as to be in contact with the second conductive type amorphous semiconductor film 5. The electrode 12 is formed.

  Here, the first electrode 11 and the second electrode 12 extend in a direction in which the first electrode 11 and the second electrode 12 form an angle of 90 ° ± 5 ° with the sides 1a and 1b on the back surface of the semiconductor substrate 1, respectively. In addition, the semiconductor substrate 1 is formed to include a linear groove 6 extending in a direction that forms an angle of 90 ° ± 5 ° with the first electrode 11 and the second electrode 12. In addition, although the formation method of the 1st electrode 11 and the 2nd electrode 12 is not specifically limited, For example, a vapor deposition method etc. can be used.

Thus, the heterojunction back contact cell 10 of Embodiment 1 is completed.
<Effect>
In the heterojunction back contact cell 10 of Embodiment 1, as shown in FIG. 3B, the extending direction 24 of the linear groove 6 is different from the extending direction 21 of the first electrode 11 and the second electrode 12. The angle is 90 ° ± 5 °. That is, the first electrode 11 and the second electrode 12 are arranged so as to extend in a direction that forms an angle of 90 ° ± 5 ° with the extending direction of the linear groove 6.

  FIG. 16 shows a schematic enlarged cross-sectional view of an example of the back surface of the heterojunction back contact cell 10 of Embodiment 1 along the extending direction 21 of the first electrode 11 and the second electrode 12, and FIG. The typical expanded sectional view of the other example of the back surface of the heterojunction type back contact cell 10 of Embodiment 1 along the extension direction 21 of the 1st electrode 11 and the 2nd electrode 12 is shown. FIG. 16 shows an example in which the thickness H of the first electrode 11 and the second electrode 12 is thinner than the depth D of the linear groove, and FIG. 17 shows the first electrode 11 and the second electrode. An example in which the thickness H of 12 is thicker than the depth D of the linear groove is shown.

  As shown in FIGS. 16 and 17, in the heterojunction back contact cell 10 of the first embodiment, the first electrode 11 and the second electrode 12 are anchored by unevenness caused by the linear groove 6 on the back surface of the semiconductor substrate 1. An effect can be expressed. Thereby, peeling of the 1st electrode 11 and the 2nd electrode 12 can be suppressed compared with the solar cell of patent document 1 in which the electrode was provided in the back surface of the semiconductor substrate in parallel with the extension direction of a linear groove | channel.

  Furthermore, as a result of intensive studies by the present inventors, the first electrode 11 and the second electrode 12 are extended within a range that forms an angle of 90 ° ± 5 ° with the extending direction of the linear groove 6. As compared with the case where the first electrode 11 and the second electrode 12 are provided so as to extend outside the range, the separation of the first electrode 11 and the second electrode 12 is remarkably suppressed. It was confirmed that it was possible.

  For the above reason, in the heterojunction back contact cell 10 of Embodiment 1, the peeling of the first electrode 11 and the second electrode 12 can be suppressed as compared with the conventional solar cell of Patent Document 1.

[Embodiment 2]
FIG. 18 is a schematic plan view of the back surface of the heterojunction back contact cell of Embodiment 2, which is another example of the photoelectric conversion element of the embodiment. As shown in FIG. 18, the heterojunction back contact cell 10 of Embodiment 2 is characterized by including a first tab electrode 11a and a second tab electrode 12a. The first tab electrode 11 a extends in a different direction from the first electrode 11, is electrically connected to one end of each of the plurality of first electrodes 11, and electrically connects the plurality of first electrodes 11. Yes. The second tab electrode 12 a extends in a different direction from the second electrode 12 and is electrically connected to one end of each of the plurality of second electrodes 12 to electrically connect the plurality of second electrodes 12. doing.

  Since the description other than the above in Embodiment 2 is the same as that in Embodiment 1, the description thereof will not be repeated.

[Embodiment 3]
Embodiment 3 is characterized in that a loose abrasive is used to cut an n-type silicon single crystal ingot with a wire saw. FIG. 19 shows a diagram illustrating an example of a process of cutting the n-type silicon single crystal ingot 30 of Embodiment 3 using the loose abrasive grains 52 and the wire saw 53. As the wire saw 53, a wire saw in which the fixed abrasive grains 33b are not fixed to the outer peripheral surface of the core wire 33a shown in FIG. 6 is used. The n-type silicon single crystal ingot 30 is cut by the free abrasive grains 52 and the wire saw 53 by mixing slurry obtained by mixing free abrasive grains 52 such as silicon carbide and diamond with an oil-based or water-soluble cutting fluid 51. It is performed while supplying the surface of the ingot 30.

  Since the description other than the above in the third embodiment is the same as that in the first and second embodiments, the description thereof will not be repeated.

[Embodiment 4]
In FIG. 20, the typical sectional drawing of the back surface electrode type photovoltaic cell of Embodiment 4 which is another example of the photoelectric conversion element of Embodiment is shown. As shown in FIG. 20, the back electrode type solar battery cell 100 of Embodiment 4 is a p-type as a first conductivity type impurity-containing region provided on the back surface of the semiconductor substrate 1 and the semiconductor substrate 1 with a space therebetween. An impurity diffusion region 65 and an n-type impurity diffusion region 63 as a second conductivity type impurity-containing region are provided. The first electrode 11 is provided on the first conductivity type impurity containing region 65, and the second electrode 12 is provided on the second conductivity type impurity containing region 63.

  Further, a dielectric film 67 such as a silicon oxide film or a silicon nitride film is provided on the back surface of the semiconductor substrate 1, and the silicon oxide film or silicon nitride is also provided on the texture structure 68 on the light receiving surface of the semiconductor substrate 1. A dielectric film 69 such as a film is provided.

  Hereinafter, an example of a method for manufacturing the back electrode type solar battery cell of Embodiment 4 will be described with reference to schematic cross-sectional views of FIGS.

  First, as shown in FIG. 21, a diffusion mask 62 is provided on each of the light receiving surface and the back surface of the semiconductor substrate 1, and an opening 61 a is provided in a part of the diffusion suppression mask 62 on the back surface of the semiconductor substrate 1. In addition, the formation method of the opening part 61a is not specifically limited, For example, methods, such as photolithography, can be used.

Next, as shown in FIG. 22, by flowing an n-type impurity-containing gas 64, n-type impurities are introduced into the back surface of the semiconductor substrate 1 exposed from the opening 61 a of the diffusion suppression mask 62 on the back surface of the semiconductor substrate 1. An n-type impurity diffusion region 63 is formed by diffusing. As the n-type impurity-containing gas 64, for example, POCl ₃ containing phosphorus which is an n-type impurity can be used. The n-type impurity diffusion region 63 may be a region having an n-type impurity concentration higher than that of the semiconductor substrate 1.

  Next, after all of the diffusion suppression masks 62 on the light receiving surface and the back surface of the semiconductor substrate 1 are once removed, the diffusion suppression mask 62 is installed again on the entire surfaces of the light receiving surface and the back surface of the semiconductor substrate 1, as shown in FIG. In addition, an opening 61 b is provided in part of the diffusion suppression mask 62 on the back surface of the semiconductor substrate 1.

  Next, as shown in FIG. 24, by flowing a p-type impurity-containing gas 66, p-type impurities are introduced into the back surface of the semiconductor substrate 1 exposed from the opening 61 b of the diffusion suppression mask 62 on the back surface of the semiconductor substrate 1. A p-type impurity diffusion region 65 is formed by diffusing.

  Next, as shown in FIG. 25, all diffusion suppression masks 62 on the light receiving surface and the back surface of the semiconductor substrate 1 are removed. Next, as shown in FIG. 26, a dielectric film 67 is formed on the entire back surface of the semiconductor substrate 1.

  Next, as shown in FIG. 27, the texture structure 68 is formed by texture-etching the light-receiving surface of the semiconductor substrate 1.

  Next, as shown in FIG. 28, a dielectric film 69 is formed on the texture structure 68 on the light receiving surface of the semiconductor substrate 1. Next, as shown in FIG. 29, contact holes 70 and 71 are formed by removing a part of the dielectric film 67 on the back surface of the semiconductor substrate 1. In addition, the formation method of the contact holes 70 and 71 is not specifically limited, For example, methods, such as photolithography, can be used.

  Thereafter, as shown in FIG. 20, the first electrode 11 electrically connected to the p-type impurity diffusion region 65 through the contact hole 71 is formed, and also electrically connected to the n-type impurity diffusion region 63 through the contact hole 70. The second electrode 12 to be formed is formed.

  Again, the first electrode 11 and the second electrode 12 extend in a direction in which the first electrode 11 and the second electrode 12 form an angle of 90 ° ± 5 ° with the sides 1a and 1b on the back surface of the semiconductor substrate 1, respectively. In addition, the semiconductor substrate 1 is formed to include a linear groove 6 extending in a direction that forms an angle of 90 ° ± 5 ° with the first electrode 11 and the second electrode 12.

  Since the description other than the above in Embodiment 4 is the same as that in Embodiments 1 to 3, the description thereof will not be repeated.

[Appendix]
An embodiment disclosed herein includes a semiconductor substrate of a first conductivity type or a second conductivity type, a first conductivity type portion and a second conductivity type portion provided on one side of the semiconductor substrate, and a first conductivity type. A first electrode on the portion and a second electrode on the second conductivity type portion, wherein the first electrode and the second electrode extend in a direction that forms an angle of 90 ° ± 5 ° with the side of the semiconductor substrate The semiconductor substrate is a photoelectric conversion element including a linear groove extending in a direction that forms an angle of 90 ° ± 5 ° with the first electrode and the second electrode. By adopting such a configuration, the first electrode and the second electrode can have an anchor effect due to the unevenness caused by the linear groove on the back surface of the semiconductor substrate 1, and therefore, parallel to the extending direction of the linear groove. Compared with the solar cell of Patent Document 1 in which an electrode is provided on the back surface of the semiconductor substrate, peeling of the first electrode and the second electrode can be suppressed.

  In the photoelectric conversion element of the embodiment disclosed herein, the semiconductor substrate preferably has a polygonal surface. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  The photoelectric conversion element of the embodiment disclosed herein preferably further includes a first tab electrode that extends in a different direction from the first electrode and electrically connects a plurality of the first electrodes. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  The photoelectric conversion element of the embodiment disclosed herein preferably further includes a second tab electrode that extends in a different direction from the second electrode and electrically connects a plurality of the second electrodes. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  In the photoelectric conversion element of the embodiment disclosed herein, it is preferable that the first electrode and the second electrode are provided with a space therebetween. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  In the photoelectric conversion element of the embodiment disclosed herein, the first electrode and the second electrode are preferably provided alternately. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  In the photoelectric conversion element of the embodiment disclosed herein, the linear groove preferably includes a saw mark. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  In the photoelectric conversion element of the embodiment disclosed herein, it is preferable that the thickness of the first electrode is thinner than the depth of the linear groove. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  In the photoelectric conversion element of the embodiment disclosed herein, it is preferable that the thickness of the first electrode is thicker than the depth of the linear groove. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  In the photoelectric conversion element of the embodiment disclosed herein, it is preferable that the thickness of the second electrode is thinner than the depth of the linear groove. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  In the photoelectric conversion element of the embodiment disclosed herein, the thickness of the second electrode is preferably thicker than the depth of the linear groove. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  In the photoelectric conversion element of the embodiment disclosed herein, the length of the linear groove is preferably longer than 3 cm. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  In the photoelectric conversion element of the embodiment disclosed herein, the semiconductor substrate preferably contains silicon. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  In the photoelectric conversion element of the embodiment disclosed herein, it is preferable that the first conductivity type portion includes a first conductivity type amorphous semiconductor film. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  In the photoelectric conversion element of the embodiment disclosed herein, the first electrode is preferably provided on the first conductive type amorphous semiconductor film. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  In the photoelectric conversion element of the embodiment disclosed herein, the first conductive amorphous semiconductor film preferably includes a first conductive amorphous silicon film. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  The photoelectric conversion element according to the embodiment disclosed herein preferably further includes a first i-type amorphous semiconductor film between the semiconductor substrate and the first conductive type amorphous semiconductor film. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  In the photoelectric conversion element of the embodiment disclosed herein, the first i-type amorphous semiconductor film preferably includes an i-type amorphous silicon film. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  In the photoelectric conversion element of the embodiment disclosed herein, the second conductivity type part preferably includes a second conductivity type amorphous semiconductor film.

  In the photoelectric conversion element of the embodiment disclosed herein, the second electrode is preferably provided on the second conductivity type amorphous semiconductor film. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  In the photoelectric conversion element of the embodiment disclosed herein, the second conductivity type amorphous semiconductor film preferably includes a second conductivity type amorphous silicon film. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  The photoelectric conversion element according to the embodiment disclosed herein preferably further includes a second i-type amorphous semiconductor film between the semiconductor substrate and the second conductive amorphous semiconductor film. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  In the photoelectric conversion element of the embodiment disclosed herein, the second i-type amorphous semiconductor film preferably includes an i-type amorphous silicon film. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  In the photoelectric conversion element of the embodiment disclosed herein, the first conductivity type part preferably includes a first conductivity type impurity-containing region. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  In the photoelectric conversion element of the embodiment disclosed herein, the first electrode is preferably provided on the first conductivity type impurity-containing region. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  In the photoelectric conversion element of the embodiment disclosed herein, the second conductivity type part preferably includes a second conductivity type impurity-containing region. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  In the photoelectric conversion element of the embodiment disclosed herein, the second electrode is preferably provided on the second conductivity type impurity-containing region. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  The embodiment disclosed herein includes a step of cutting a semiconductor crystal with a wire saw to form a semiconductor substrate of a first conductivity type or a second conductivity type, a first conductivity type portion and a second conductivity type on one side of the semiconductor substrate. Forming a first electrode by a step of forming a conductive type portion, a step of forming a first electrode on the first conductive type portion, and a step of forming a second electrode on the second conductive type portion. In the step and the step of forming the second electrode, the first electrode and the second electrode respectively extend in a direction that forms an angle of 90 ° ± 5 ° with the side of the semiconductor substrate, and the semiconductor substrate It is a manufacturing method of a photoelectric conversion element formed so as to include a linear groove extending in a direction forming an angle of 90 ° ± 5 ° with the second electrode. By adopting such a configuration, the anchor effect appears in the first electrode and the second electrode due to the unevenness generated on the formation surface of the first electrode and the second electrode due to the linear groove on the back surface of the semiconductor substrate. The first electrode and the second electrode can be prevented from peeling off as compared with the solar cell of Patent Document 1 in which an electrode is provided on the back surface of the semiconductor substrate in parallel with the extending direction of the linear groove.

  In the method for manufacturing a photoelectric conversion element of the embodiment disclosed herein, it is preferable that the semiconductor crystal is cut with a wire saw using fixed abrasive grains or loose abrasive grains. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  In the method for manufacturing a photoelectric conversion element according to the embodiment disclosed herein, the linear groove preferably includes a saw mark. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  In the method for manufacturing a photoelectric conversion element according to the embodiment disclosed herein, the semiconductor substrate preferably has a polygonal surface. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  The manufacturing method of the photoelectric conversion element of the embodiment disclosed herein further includes a step of forming a first tab electrode that extends in a different direction from the first electrode and electrically connects a plurality of the first electrodes. Is preferred. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  The manufacturing method of the photoelectric conversion element of the embodiment disclosed herein further includes a step of forming a second tab electrode that extends in a different direction from the second electrode and electrically connects a plurality of the second electrodes. Is preferred. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  In the step of forming the first electrode and the step of forming the second electrode of the method for manufacturing the photoelectric conversion element according to the embodiment disclosed herein, the first electrode and the second electrode are arranged with a space therebetween. Thus, it is preferable that the first electrode and the second electrode are formed. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  In the step of forming the first electrode and the step of forming the second electrode of the method for manufacturing the photoelectric conversion element according to the embodiment disclosed herein, the first electrode and the second electrode are alternately arranged. One electrode and a second electrode are preferably formed. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  In the method for manufacturing a photoelectric conversion element according to the embodiment disclosed herein, the length of the linear groove is preferably longer than 3 cm. Also in this case, peeling of the first electrode and the second electrode can be suppressed.

  Although the embodiments of the present invention have been described above, it is also planned from the beginning to combine the configurations of the above-described embodiments as appropriate.

  It should be thought that embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  Embodiment disclosed here can be utilized for photoelectric conversion elements, such as a heterojunction type | mold back contact cell and a back surface electrode type photovoltaic cell, and its manufacturing method.

  DESCRIPTION OF SYMBOLS 1 Semiconductor substrate, 1a, 1b side, 2 1st i type amorphous semiconductor film, 3 1st conductivity type amorphous semiconductor film, 4 2nd i type amorphous semiconductor film, 5 2nd conductivity type non- Crystalline semiconductor film, 6 linear groove, 10 heterojunction back contact cell, 11 first electrode, 11a first tab electrode, 12 second electrode, 12a second tab electrode, 21 extension of first electrode and second electrode Current direction, 22 length direction of the side of the back surface of the semiconductor substrate, 23 range of direction forming an angle of 90 ° ± 5 ° with the length direction of the back surface side of the semiconductor substrate, 24 extending direction of the linear groove, 25 Range of direction forming an angle of 90 ° ± 5 ° with the extending direction of the first electrode and the second electrode, 30 n-type silicon single crystal ingot, 31, 32 guide roller, 33 wire saw, 33a core wire, 33b fixed abrasive, 34, 35 Arrow, 41, 42 Etching mask 51, cutting fluid, 52 loose abrasive, 53 wire saw, 61a, 61b opening, 62 diffusion suppression mask, 63 n-type impurity diffusion region, 64 n-type impurity-containing gas, 65 p-type impurity diffusion region, 66 p-type impurity Containing gas, 67,69 dielectric film, 68 texture structure, 70,71 contact hole, 100 back electrode type solar cell.

Claims (5)

A semiconductor substrate of a first conductivity type or a second conductivity type;
A first conductive type semiconductor film and a second conductive type semiconductor film provided on the back side of the semiconductor substrate;
A first electrode on the first conductivity type semiconductor film ;
A second electrode on the second conductivity type semiconductor film ,
The first electrode and the second electrode extend in a direction that forms an angle of 90 ° ± 5 ° with a side of the semiconductor substrate,
The semiconductor substrate includes a linear groove extending in a direction that forms an angle of 90 ° ± 5 ° with the first electrode and the second electrode.   The photoelectric conversion element according to claim 1, wherein the semiconductor substrate has a polygonal surface.   The photoelectric conversion element according to claim 1, wherein the linear groove includes a saw mark. Cutting the semiconductor crystal with a wire saw to form a semiconductor substrate of the first conductivity type or the second conductivity type;
Forming a first conductivity type semiconductor layer and the second conductive type semiconductor layer on the back surface side of the semiconductor substrate,
Forming a first electrode on the first conductive semiconductor film ;
Forming a second electrode on the second conductivity type semiconductor film , and
In the step of forming the first electrode and the step of forming the second electrode, each of the first electrode and the second electrode extends in a direction that forms an angle of 90 ° ± 5 ° with the side of the semiconductor substrate. And a method of manufacturing a photoelectric conversion element, wherein the semiconductor substrate is formed to include a linear groove extending in a direction that forms an angle of 90 ° ± 5 ° with the first electrode and the second electrode.   The method of manufacturing a photoelectric conversion element according to claim 4, wherein the cutting of the semiconductor crystal by the wire saw is performed using fixed abrasive grains or loose abrasive grains.

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