JP6013198B2 - 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, there is reflection and absorption of sunlight at the electrode, so the amount of sunlight incident by the area of the electrode is reduced, so the electrode is formed only on the back surface. Development of solar cells (back contact cells) is in progress.

  Among these, heterojunction back contact cells have been reported by various research institutions as high-efficiency solar cells having a conversion efficiency exceeding 20%. However, since the structure of the heterojunction back contact cell is complicated and its manufacturing process is also complicated, there is a demand for simplification of the manufacturing process.

  For example, Patent Document 1 discloses an invention in which the manufacturing process of a heterojunction back contact cell is simplified.

  Hereinafter, a method of manufacturing a heterojunction back contact cell disclosed in Patent Document 1 will be described with reference to schematic cross-sectional views of FIGS.

  First, as shown in FIG. 13, a semiconductor substrate 101 made of p-type crystalline silicon is prepared. Next, as shown in FIG. 14, on the back surface of the semiconductor substrate 101, an i-type silicon thin film layer 102 made of an i-type hydrogenated amorphous silicon film and a reverse conductivity type layer made of an n-type hydrogenated amorphous silicon film. 103 are formed in this order.

  Next, as shown in FIG. 15, on the back surface of the reverse conductivity type layer 103, an oxide transparent conductive material layer 104 made of ITO or the like, a reflective layer 105 containing ultra-thin Ag as a main component, and Al as a main component. Are formed in this order.

  Next, as shown in FIG. 16, a part of the back surface of the conductive layer 106 is irradiated with a fundamental wave of YAG laser light (wavelength 1.06 μm), whereby a part of the conductive layer 106 is heated and melted, and Al is dissolved. A heterojunction through contact portion 108 as a main component is formed. Here, the heterojunction through-contact portion 108 is a layer that electrically connects the semiconductor substrate 101 and the conductive layer 106, and Al diffuses into the region on the back surface of the semiconductor substrate 101 that is in contact with the heterojunction through-contact portion 108. P + region 107.

  Next, as shown in FIG. 17, by removing a part of the back electrode composed of the oxide transparent conductive material layer 104, the reflective layer 105, and the conductive layer 106 in the thickness direction, the back electrode is An electrode separation portion 109, which is an opening for separation into a plurality of portions, is formed.

  Next, as shown in FIG. 18, the texture structure 110 is formed on the light receiving surface of the semiconductor substrate 1 by performing texture etching on the light receiving surface of the semiconductor substrate 1.

  Next, as shown in FIG. 19, an insulating layer 111 is formed so as to expose only a part of the back surface of the conductive layer 106 and fill the electrode separation portion 109.

  Next, as shown in FIG. 20, the positive electrode extraction electrode 112 is formed so as to be in contact with the back surface of the conductive layer 106 connected to the heterojunction through contact portion 108 and is not connected to the heterojunction through contact portion 108. A negative electrode extraction electrode 113 is formed so as to be in contact with the back surface of the conductive layer 106.

  Thereafter, as shown in FIG. 21, a surface passivation layer 114 and an antireflection layer 115 are formed in this order on the texture structure 110 of the light receiving surface of the semiconductor substrate 101, and the heterojunction back contact cell described in Patent Document 1 is formed. Is completed.

JP 2009-152222 A

  In the method of manufacturing a heterojunction back contact cell disclosed in Patent Document 1, the heterojunction through contact portion 108 is formed by irradiating a fundamental wave of YAG laser light.

  However, the method disclosed in Patent Document 1 has at least the following two problems (i) and (ii).

  (I) Since the heterojunction through contact portion 108 formed by irradiating the fundamental wave of the YAG laser beam is in direct contact with the p + region 107 of the semiconductor substrate 101, the passivation effect is not exhibited.

  (Ii) In the heterojunction back contact cell, the conversion efficiency is higher when n-type crystalline silicon is used than when p-type crystalline silicon is used as the semiconductor substrate 101, but the n-type is diffused due to Al diffusion. It is not suitable to form the p + region 107 in the semiconductor substrate 101 made of crystalline silicon.

  In any case, the method disclosed in Patent Document 1 is a process in which it is difficult to manufacture a heterojunction back contact cell.

  In view of the above circumstances, an object of the present invention is to provide a photoelectric conversion element capable of manufacturing a heterojunction back contact cell having a complicated structure by a simple manufacturing process and a method for manufacturing the photoelectric conversion element. It is in.

  The present invention relates to a first conductivity type semiconductor substrate, an i-type amorphous film, a p-type amorphous film, and a first layer, which are sequentially stacked on a partial region of one surface of the semiconductor substrate. The n-type non-conductive layer, the n-type amorphous film, the second transparent conductive film, the first electrode, and the other part of the surface of the semiconductor substrate are sequentially stacked. The photoelectric conversion element includes a crystalline film, a second transparent conductive film, and a second electrode. With such a configuration, it is possible to manufacture a heterojunction back contact cell having a complicated structure by a simple manufacturing process.

  Further, according to the present invention, an i-type amorphous film, a p-type amorphous film, and a first transparent conductive film are laminated in this order on the entire surface of one surface of the first conductivity type semiconductor substrate. The step of forming the first stacked body on the surface of the semiconductor substrate and the removal of a part of the first stacked body by irradiation with the first laser beam, The n-type amorphous film and the second transparent conductive film are stacked in this order so as to cover the exposed step and the exposed surface of the semiconductor substrate and the first stacked body, thereby exposing the semiconductor substrate. Forming a second laminate on the surface, separating the first laminate and the second laminate by irradiation with a second laser beam, and forming a second laminate on the first laminate. Forming a first electrode, and forming a second electrode on the second stacked body, the first laser beam And the second laser light are at least one of the second harmonic of the YAG laser light and the third harmonic of the YAG laser light, respectively, and the irradiation time of the first laser light and the irradiation time of the second laser light Are each a method for producing a photoelectric conversion element of 1 nanosecond or less. With such a configuration, damage to the semiconductor substrate due to irradiation with the first laser light and the second laser light can be reduced, and a heterojunction back contact cell having a complicated structure can be simplified. It becomes possible to manufacture in a simple manufacturing process.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the photoelectric conversion element which can manufacture the heterojunction type back contact cell which has a complicated structure with a simple manufacturing process, and a photoelectric conversion element can be provided.

It is a typical sectional view of a heterojunction type back contact cell of an embodiment. It is typical sectional drawing illustrating a part of manufacturing process of an example of the manufacturing method of the heterojunction type back contact cell of embodiment. It is typical sectional drawing illustrating a part of manufacturing process of an example of the manufacturing method of the heterojunction type back contact cell of embodiment. It is typical sectional drawing illustrating a part of manufacturing process of an example of the manufacturing method of the heterojunction type back contact cell of embodiment. It is typical sectional drawing illustrating a part of manufacturing process of an example of the manufacturing method of the heterojunction type back contact cell of embodiment. It is typical sectional drawing illustrating a part of manufacturing process of an example of the manufacturing method of the heterojunction type back contact cell of embodiment. Energy (eV) and absorption coefficient (cm ⁻ ) of light irradiated to crystalline silicon (c-Si), hydrogenated amorphous silicon (a-Si: H) and hydrogenated microcrystalline silicon (μc-Si: H) It is a figure which shows the relationship with ¹ ). It is typical sectional drawing illustrating a part of manufacturing process of an example of the manufacturing method of the heterojunction type back contact cell of embodiment. It is typical sectional drawing illustrating a part of manufacturing process of an example of the manufacturing method of the heterojunction type back contact cell of embodiment. It is typical sectional drawing illustrating a part of manufacturing process of an example of the manufacturing method of the heterojunction type back contact cell of embodiment. It is typical sectional drawing illustrating a part of manufacturing process of an example of the manufacturing method of the heterojunction type back contact cell of embodiment. It is a typical top view of an example of the wiring sheet for taking out electric power from the heterojunction type back contact cell of an embodiment. It is typical sectional drawing illustrating a part of manufacturing process of the manufacturing method of the heterojunction type back contact cell disclosed by the conventional patent document 1. FIG. It is typical sectional drawing illustrating a part of manufacturing process of the manufacturing method of the heterojunction type back contact cell disclosed by the conventional patent document 1. FIG. It is typical sectional drawing illustrating a part of manufacturing process of the manufacturing method of the heterojunction type back contact cell disclosed by the conventional patent document 1. FIG. It is typical sectional drawing illustrating a part of manufacturing process of the manufacturing method of the heterojunction type back contact cell disclosed by the conventional patent document 1. FIG. It is typical sectional drawing illustrating a part of manufacturing process of the manufacturing method of the heterojunction type back contact cell disclosed by the conventional patent document 1. FIG. It is typical sectional drawing illustrating a part of manufacturing process of the manufacturing method of the heterojunction type back contact cell disclosed by the conventional patent document 1. FIG. It is typical sectional drawing illustrating a part of manufacturing process of the manufacturing method of the heterojunction type back contact cell disclosed by the conventional patent document 1. FIG. It is typical sectional drawing illustrating a part of manufacturing process of the manufacturing method of the heterojunction type back contact cell disclosed by the conventional patent document 1. FIG. It is typical sectional drawing illustrating a part of manufacturing process of the manufacturing method of the heterojunction type back contact cell disclosed by the conventional patent document 1. FIG.

  Embodiments of the present invention will be described below. In the drawings of the present invention, the same reference numerals represent the same or corresponding parts.

  FIG. 1 is a schematic cross-sectional view of a heterojunction back contact cell according to an embodiment which is an example of the photoelectric conversion element of the present invention. As shown in FIG. 1, the heterojunction back contact cell of the embodiment has a semiconductor substrate 1 made of n-type single crystal silicon, and on the light receiving surface that is one surface of the semiconductor substrate 1, A passivation film 2 and an antireflection film 3 are sequentially stacked from the semiconductor substrate 1 side.

  An i-type amorphous film 4 made of i-type amorphous silicon and a p-type non-layer made of p-type amorphous silicon are formed on a part of the back surface which is the surface opposite to the light-receiving surface of the semiconductor substrate 1. A crystalline film 5, a first transparent conductive film 6, an n-type amorphous film 8 made of n-type amorphous silicon, a second transparent conductive film 9, and a first electrode 12 are sequentially stacked. ing.

  An n-type amorphous film 8, a second transparent conductive film 9, and a second electrode 13 are sequentially stacked on another partial region of the back surface of the semiconductor substrate 1.

  Note that a first stacked body 10 in which an i-type amorphous film 4, a p-type amorphous film 5, and a first transparent conductive film 6 are sequentially stacked on the back surface of the semiconductor substrate 1 from the semiconductor substrate 1 side. The horizontal distance W1 between the end face of the first electrode 12 and the end face on the opposite side of the first electrode 12 can be, for example, about 1000 μm.

  Moreover, the horizontal distance W2 between the end surface of the first stacked body 10 and the end surface of the first stacked body 10 adjacent thereto can be set to, for example, about 1500 μm. Note that a second n-type amorphous film 8 and a second transparent conductive film 9 are sequentially stacked from the semiconductor substrate 1 side on the back surface of the semiconductor substrate 1 between the adjacent first stacked bodies 10. The laminated body 20 is formed.

  Further, the horizontal distances W3 and W4 between the end face of the first electrode 12 and the end face of the second electrode 13 adjacent to the end face can be set to about 200 μm, for example.

  Thereby, the width | variety of the 2nd electrode 13 can be about 200 micrometers from the formula of W2- (W1 + W3 + W4).

  Hereinafter, an example of a method for manufacturing the heterojunction back contact cell of the embodiment will be described with reference to schematic cross-sectional views of FIGS. First, as shown in FIG. 2, the passivation film 2 is laminated on the entire light receiving surface of the semiconductor substrate 1.

  For example, a silicon oxide film, a silicon nitride film, or a hydrogenated amorphous silicon film can be used as the passivation film 2. The thickness of the passivation film 2 is not particularly limited, but can be, for example, 5 nm or more and 10 nm or less.

  The method for laminating the passivation film 2 is not particularly limited, and for example, a plasma CVD (Chemical Vapor Deposition) method or the like can be used.

Next, as shown in FIG. 3, an antireflection film 3 is laminated on the entire surface of the passivation film 2.
As the antireflection film 3, for example, a film having a refractive index of about 2.0 such as a silicon nitride film or a transparent conductive oxide film can be used. The thickness of the antireflection film 3 is not particularly limited, but can be, for example, about 100 nm.

  The method for stacking the antireflection film 3 is not particularly limited, and for example, a plasma CVD method or a sputtering method can be used.

  Next, as shown in FIG. 4, an i-type amorphous film 4 made of i-type amorphous silicon and a p-type amorphous film 5 made of p-type amorphous silicon are formed on the entire back surface of the semiconductor substrate 1. In this order, the layers are stacked by, for example, a plasma CVD method.

  Although n-type single crystal silicon is preferable as the semiconductor substrate 1 from the viewpoint of improving the conversion efficiency, for example, a conventionally known p-type semiconductor substrate may be used. Moreover, as the semiconductor substrate 1, it is preferable to use a semiconductor substrate in which a texture structure (not shown) is formed on the light receiving surface of the semiconductor substrate 1 in advance.

  Although the thickness of the semiconductor substrate 1 is not specifically limited, For example, it can be 100 micrometers or more and 300 micrometers or less, Preferably it can be 100 micrometers or more and 200 micrometers or less. Further, the specific resistance of the semiconductor substrate 1 is not particularly limited, but may be, for example, 0.1 Ω · cm or more and 1 Ω · cm or less.

  The thickness of the i-type amorphous film 4 is not particularly limited, but can be about 3 nm, for example.

  The thickness of the p-type amorphous film 5 is not particularly limited, but can be about 7 nm, for example.

As the p-type impurity contained in the p-type amorphous film 5, for example, boron can be used, and the p-type impurity concentration of the p-type amorphous film 5 is, for example, about 5 × 10 ¹⁹ / cm ³ . be able to.

  Note that “i-type” in this specification means that n-type or p-type impurities are not intentionally doped. For example, after manufacturing a photoelectric conversion element, n-type or p-type impurities are not present. A slight n-type or p-type conductivity may be exhibited due to unavoidable diffusion.

  In the present specification, “amorphous silicon” includes hydrogen atoms terminated with dangling bonds of silicon atoms such as amorphous silicon hydride.

  Next, as shown in FIG. 5, a first transparent conductive film 6 is laminated on the entire back surface of the p-type amorphous film 5. As a result, the i-type amorphous film 4, the p-type amorphous film 5, and the first transparent conductive film 6 are laminated in this order on the back surface of the semiconductor substrate 1 from the semiconductor substrate 1 side. A first laminate 10 is formed.

  As the first transparent conductive film 6, a conductive transparent material can be used without any particular limitation, and among these, it is preferable to use a transparent conductive film containing zinc oxide. When a transparent conductive film containing zinc oxide is used for the first transparent conductive film 6, the cost tends to be advantageous.

  Although the lamination | stacking method of the 1st transparent conductive film 6 is not specifically limited, For example, it can laminate | stack by sputtering method. Further, the thickness of the first transparent conductive film 6 is not particularly limited, but can be set to 60 nm or less, for example.

  Next, as shown in FIG. 6, a part of the first stacked body 10 is removed by irradiating a part of the back surface of the first stacked body 10 with the first laser beam 7, and the semiconductor substrate A part of the back surface of 1 is exposed.

  As the first laser light 7, light having a wavelength corresponding to energy having a larger absorption coefficient is used in the i-type amorphous film 4 and the p-type amorphous film 5 than in the semiconductor substrate 1. Are selected from the group consisting of the second harmonic (wavelength 532 nm) of the YAG laser light, the third harmonic (wavelength 355 nm) of the YAG laser light, and the fourth harmonic (wavelength 266 nm) of the YAG laser light. It is more preferable to use at least one, and from the viewpoint of reducing thermal damage, it is particularly preferable to use the second harmonic of the YAG laser light or the third harmonic of the YAG laser light.

  For example, when the i-type amorphous film 4 and the p-type amorphous film 5 are made of hydrogenated amorphous silicon and the semiconductor substrate 1 is made of crystalline silicon, as shown in FIG. The absorption coefficient of hydrogenated amorphous silicon with respect to harmonics is 10 times or more that of crystalline silicon. Therefore, in this case, only the i-type amorphous film 4 and the p-type amorphous film 5 in the second harmonic irradiation portion of the YAG laser light are selectively evaporated to remove the p-type non-irradiation in the irradiation portion. Since it can be removed together with the first transparent conductive film 6 on the crystalline film 5, a part of the back surface of the semiconductor substrate 1 can be exposed more efficiently.

Note that FIG. 7 shows energy (eV) of light irradiated to crystalline silicon (c-Si), hydrogenated amorphous silicon (a-Si: H), and hydrogenated microcrystalline silicon (μc-Si: H). And the absorption coefficient (cm ⁻¹ ).

  Moreover, it is preferable that the irradiation time of the 1st laser beam 7 is 1 nanosecond or less. When the irradiation time of the first laser beam 7 is 1 nanosecond or less, there is a tendency that damage to the underlying semiconductor substrate 1 can be reduced.

  Further, the removal width W5 of the first stacked body 10 by the irradiation with the first laser beam 7 shown in FIG. 6 can be set to, for example, about 500 μm.

  Next, as shown in FIG. 8, an n-type amorphous film 8 is laminated by, for example, a plasma CVD method so as to cover the exposed back surface of the semiconductor substrate 1 and the first laminated body 10. Since the n-type amorphous film 8 is laminated on the surface of the first transparent conductive film 6, the junction between the first transparent conductive film 6 and the n-type amorphous film 8 is an ohmic junction. Become.

  The n-type amorphous film 8 is not limited to a film made of n-type amorphous silicon. For example, a conventionally known n-type amorphous semiconductor film may be used. The thickness of the n-type amorphous film 8 is not particularly limited, but can be about 30 nm, for example.

As the n-type impurity contained in the n-type amorphous film 8, for example, phosphorus can be used, and the n-type impurity concentration of the n-type amorphous film 8 is, for example, about 5 × 10 ¹⁹ / cm ³ . be able to.

Further, it is preferable to form an n-type semiconductor layer having an n-type impurity concentration of, for example, about 1 × 10 ¹⁵ pieces / cm ³ to 1 × 10 ¹⁸ pieces / cm ³ before forming the n-type amorphous film 8. . In this case, the open circuit voltage of the heterojunction back contact cell of the embodiment tends to be improved.

  Next, as shown in FIG. 9, the second transparent conductive film 9 is laminated on the entire back surface of the n-type amorphous film 8 that covers the exposed back surface of the semiconductor substrate 1 and the first stacked body 10. As a result, a second stacked body 20 is formed on the back surface of the semiconductor substrate 1 by laminating the n-type amorphous film 8 and the second transparent conductive film 9 in this order from the semiconductor substrate 1 side. .

  As the second transparent conductive film 9, a conductive transparent material can be used without particular limitation, and among them, a transparent conductive film containing ITO (Indium Tin Oxide) is preferably used. When a transparent conductive film containing ITO is used for the second transparent conductive film 9, the adhesion with the n-type amorphous film 8 tends to be improved.

  Although the lamination | stacking method of the 2nd transparent conductive film 9 is not specifically limited, For example, it can laminate | stack by sputtering method. Further, the thickness of the second transparent conductive film 9 is not particularly limited, but can be set to 60 nm or less, for example.

  Next, as shown in FIG. 10, a part of the second stacked body 20 is removed by irradiating a part of the back surface of the second stacked body 20 with the second laser light 11, and the semiconductor substrate A part of the back surface of 1 is exposed. Thereby, the 1st laminated body 10 and the 2nd laminated body 20 are electrically isolate | separated.

  Note that, by this step, a stacked body of the n-type amorphous film 8 and the second transparent conductive film 9 remains on the first stacked body 10, but in this specification, the semiconductor substrate 1 Only the stacked body of the n-type amorphous film 8 and the second transparent conductive film 9 stacked on the back surface of the substrate is referred to as a second stacked body 20.

  As the second laser light 11, it is preferable to use light having a wavelength corresponding to energy having a larger absorption coefficient in the n-type amorphous film 8 than in the semiconductor substrate 1, and in particular, YAG laser light. Is more preferably at least one of the second harmonic (wavelength 532 nm) and the third harmonic (wavelength 355 nm) of the YAG laser light, and particularly preferably the second harmonic of the YAG laser light.

  For example, when the n-type amorphous film 8 is made of hydrogenated amorphous silicon and the semiconductor substrate 1 is made of crystalline silicon, as shown in FIG. 7, the hydrogenated amorphous silicon with respect to the second harmonic of the YAG laser beam is used. The absorption coefficient is 10 times or more that of crystalline silicon. Therefore, in this case, only the n-type amorphous film 8 in the second harmonic irradiation portion of the YAG laser light is selectively evaporated, and the second on the n-type amorphous film 8 in the irradiation portion. Since it can be removed together with the transparent conductive film 9, a part of the back surface of the semiconductor substrate 1 can be exposed more efficiently.

  Moreover, it is preferable that the irradiation time of the 2nd laser beam 11 is 1 nanosecond or less. When the irradiation time of the second laser beam 11 is 1 nanosecond or less, the damage to the semiconductor substrate 1 serving as a base tends to be reduced.

  Next, as shown in FIG. 11, while applying the 1st silver paste 12a on the back surface of the 2nd transparent conductive film 9 on the 1st laminated body 10, the 2nd of the 2nd laminated body 20 A second silver paste 13 a is applied on the back surface of the transparent conductive film 9.

  Here, as the 1st silver paste 12a and the 2nd silver paste 13a, it is preferable to respectively use the silver paste whose baking temperature is 200 degrees C or less. In this case, the influence on the bonded hydrogen state of amorphous silicon tends to be reduced.

  Moreover, it is preferable that the 1st silver paste 12a and the 2nd silver paste 13a contain silver particle whose average particle diameter is less than 1000 nm. In this case, the contact resistance of the first electrode 12 and the second electrode 13 with respect to the second transparent conductive film 9 tends to be lowered.

  Moreover, as the 1st silver paste 12a and the 2nd silver paste 13a, it is preferable to use the silver paste which has a specific resistance of 1 microhm * cm or less, respectively. In this case, the contact resistance of the first electrode 12 and the second electrode 13 with respect to the second transparent conductive film 9 tends to be lowered.

  Next, by firing the first silver paste 12a and the second silver paste 13a, the first electrode 12 that is a fired silver electrode is formed on the first laminate 10 as shown in FIG. At the same time, the second electrode 13 that is a baked silver electrode is formed on the second laminate 20.

  Although the shape of the 1st electrode 12 and the 2nd electrode 13 is not specifically limited, For example, it forms in a comb shape, respectively, and it can form so that a mutual comb tooth may be arranged alternately one by one.

  Further, before forming the first electrode 12 and the second electrode 13 (before applying the first silver paste 12a and the second silver paste 13a), silver is formed on the back surface of the second transparent conductive film 9. It is preferable to form a thin film. In this case, the contact resistance of the first electrode 12 and the second electrode 13 with respect to the second transparent conductive film 9 tends to be lower. In addition, when processing a silver thin film by irradiation of the 2nd laser beam 11, it is preferable to use the 3rd harmonic or 4th harmonic of a YAG laser beam as the 2nd laser beam 11, and a YAG laser More preferably, the fourth harmonic of light is used.

  Here, the thickness of the silver thin film can be, for example, not less than 100 nm and not more than 500 nm. The silver thin film can be formed to a thickness of about 200 nm by, for example, a sputtering method.

  Thus, the heterojunction back contact cell of the embodiment having the structure shown in FIG. 1 is completed.

  FIG. 12 shows a schematic plan view of an example of a wiring sheet for extracting power from the heterojunction back contact cell of the embodiment. As shown in FIG. 12, the wiring sheet 30 receives power from the first electrode 12 and the second electrode 13 on the back surface of the heterojunction back contact cell of the embodiment on the surface of the insulating substrate 31. The p wiring 32 and the n wiring 33 for taking out may be arranged in a staggered pattern.

  That is, the first electrode 12 is placed on the p wiring 32 so that the longitudinal direction of the comb teeth of the first electrode 12 is along the longitudinal direction of the p wiring 32 that is spaced from each other. Connect electrically. Further, the second electrode 13 is placed on the n wiring 33 so that the longitudinal direction of the comb teeth of the second electrode 13 is along the longitudinal direction of the n wirings 33 that are spaced apart from each other. Connect electrically. Thereby, the heterojunction back contact cell of embodiment shown in FIG. 1 and the wiring sheet 30 shown in FIG. 12 can be connected.

  Further, the p wiring 32 of the wiring sheet 30 to which the heterojunction back contact cell of the embodiment is connected and the n wiring 33 of another wiring sheet 30 to which the heterojunction back contact cell of the embodiment is connected. By sequentially electrically connecting, the wiring sheet 30 enables the heterojunction back contact cell of the embodiment to be modularized.

  The insulating substrate 31 is not particularly limited as long as it is an insulating material, and for example, an insulating film such as a polyester film can be used. Further, the p wiring 32 and the n wiring 33 are not particularly limited as long as they are conductive materials, and for example, copper wiring or the like can be used.

  According to the method for manufacturing a heterojunction back contact cell of the embodiment, it is simpler without going through difficult steps such as formation of a heterojunction through contact portion as in the conventional method disclosed in Patent Document 1. With this process, a heterojunction back contact cell having a complicated structure can be manufactured.

  In addition, according to the method of manufacturing a heterojunction back contact cell of the embodiment, it is not necessary to perform photoresist coating and photoresist patterning processes by photolithography technique and etching technique. A heterojunction back contact cell having a complicated structure can be manufactured by a simpler manufacturing process.

  The present invention relates to a first conductivity type semiconductor substrate, an i-type amorphous film, a p-type amorphous film, and a first layer, which are sequentially stacked on a partial region of one surface of the semiconductor substrate. The n-type non-conductive layer, the n-type amorphous film, the second transparent conductive film, the first electrode, and the other part of the surface of the semiconductor substrate are sequentially stacked. The photoelectric conversion element includes a crystalline film, a second transparent conductive film, and a second electrode. With such a configuration, it is possible to manufacture a heterojunction back contact cell having a complicated structure by a simple manufacturing process.

  In the photoelectric conversion element of the present invention, the first transparent conductive film preferably contains zinc oxide. Such a configuration tends to be advantageous in terms of cost.

  In the photoelectric conversion element of the present invention, the second transparent conductive film preferably contains ITO. By setting it as such a structure, it exists in the tendency for the adhesiveness of a 2nd transparent conductive film to improve.

  Further, according to the present invention, an i-type amorphous film, a p-type amorphous film, and a first transparent conductive film are laminated in this order on the entire surface of one surface of the first conductivity type semiconductor substrate. The step of forming the first stacked body on the surface of the semiconductor substrate and the removal of a part of the first stacked body by irradiation with the first laser beam, The n-type amorphous film and the second transparent conductive film are stacked in this order so as to cover the exposed step and the exposed surface of the semiconductor substrate and the first stacked body, thereby exposing the semiconductor substrate. Forming a second laminate on the surface, separating the first laminate and the second laminate by irradiation with a second laser beam, and forming a second laminate on the first laminate. Forming a first electrode, and forming a second electrode on the second stacked body, the first laser And the second laser light is at least one of the second harmonic of the YAG laser light and the third harmonic of the YAG laser light, respectively, and the irradiation time of the first laser light and the irradiation time of the second laser light Are each a method for producing a photoelectric conversion element of 1 nanosecond or less. With such a configuration, damage to the semiconductor substrate due to irradiation with the first laser light and the second laser light can be reduced, and a heterojunction back contact cell having a complicated structure can be simplified. It becomes possible to manufacture in a simple manufacturing process.

  Moreover, in the method for manufacturing a photoelectric conversion element of the present invention, the step of forming the first electrode includes a step of applying the first silver paste on the first laminated body, and a step of firing the first silver paste. And the step of forming the second electrode includes a step of applying a second silver paste on the second laminated body and a step of firing the second silver paste, and the first silver paste The firing temperature of the first silver paste and the firing temperature of the second silver paste are each 200 ° C. or less, and the specific resistance of the first silver paste and the specific resistance of the second silver paste are 1 μΩ · cm or less, respectively. The first silver paste and the second silver paste each contain silver particles having an average particle size of less than 1000 nm, and before the step of forming the first electrode and the step of forming the second electrode, The process of forming a silver thin film on the transparent conductive film 2 Furthermore, it is preferable to include. With such a configuration, the influence of the amorphous silicon on the bonded hydrogen state can be reduced, and the contact resistance of the first electrode and the second electrode with respect to the second transparent conductive film can be reduced. it can.

  For the above reasons, according to the embodiment, a heterojunction back contact cell having a complicated structure can be manufactured by a simple manufacturing process.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. 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.

  INDUSTRIAL APPLICATION This invention can be utilized for the manufacturing method of a photoelectric conversion element and a photoelectric conversion element, and can be utilized especially for the manufacturing method of the heterojunction type back contact cell which has a complicated structure, and a heterojunction type back contact cell. .

  DESCRIPTION OF SYMBOLS 1 Semiconductor substrate, 2 Passivation film, 3 Anti-reflective film, 4 i-type amorphous film, 5 p-type amorphous film, 6 1st transparent conductive film, 7 1st laser beam, 8 n-type amorphous Film, 9 second transparent conductive film, 10 first laminated body, 11 second laser beam, 12 first electrode, 12a silver paste, 13 second electrode, 13a silver paste, 20 second laminated body 30 wiring sheet, 31 insulating substrate, 32 p wiring, 33 n wiring, 101 semiconductor substrate, 102 i-type silicon thin film layer, 103 reverse conductivity type layer, 104 oxide transparent conductive material layer, 105 reflective layer, 106 conductive Layer, 107 p + region, 108 heterojunction through contact portion, 109 electrode separation portion, 110 texture structure, 111 insulating layer, 112 positive electrode extraction electrode, 113 negative electrode extraction electrode, 114 surface passivation Layers, 115 anti-reflection layer.

Claims (5)

A first conductivity type semiconductor substrate;
An i-type amorphous film, a p-type amorphous film, a first transparent conductive film, and an n-type amorphous film, which are sequentially stacked on a partial region of one surface of the semiconductor substrate. A second transparent conductive film, a first electrode,
A photoelectric conversion element comprising an n-type amorphous film, a second transparent conductive film, and a second electrode, which are sequentially stacked on another part of the surface of the semiconductor substrate. .   The photoelectric conversion element according to claim 1, wherein the first transparent conductive film contains zinc oxide.   The photoelectric conversion element according to claim 1, wherein the second transparent conductive film contains ITO. By laminating an i-type amorphous film, a p-type amorphous film, and a first transparent conductive film in this order on the entire surface of one surface of the first conductivity type semiconductor substrate, Forming a first laminate on the surface;
Exposing a part of the surface of the semiconductor substrate by removing a part of the first stacked body by irradiation with a first laser beam;
An n-type amorphous film and a second transparent conductive film are stacked in this order so as to cover the exposed surface of the semiconductor substrate and the first stacked body, thereby exposing the semiconductor substrate. Forming a second laminate on the surface;
Separating the first stacked body and the second stacked body by irradiation with a second laser beam;
Forming a first electrode on the first laminate;
Forming a second electrode on the second laminate,
The first laser beam and the second laser beam are at least one of a second harmonic of a YAG laser beam and a third harmonic of a YAG laser beam, respectively.
The method for manufacturing a photoelectric conversion element, wherein the irradiation time of the first laser light and the irradiation time of the second laser light are each 1 nanosecond or less. The step of forming the first electrode includes a step of applying a first silver paste on the first stacked body, and a step of baking the first silver paste,
The step of forming the second electrode includes a step of applying a second silver paste on the second laminate, and a step of firing the second silver paste,
The firing temperature of the first silver paste and the firing temperature of the second silver paste are each 200 ° C. or less,
The specific resistance of the first silver paste and the specific resistance of the second silver paste are each 1 μΩ · cm or less,
Each of the first silver paste and the second silver paste includes silver particles having an average particle diameter of less than 1000 nm,
The photoelectric conversion according to claim 4, further comprising a step of forming a silver thin film on the second transparent conductive film before the step of forming the first electrode and the step of forming the second electrode. Device manufacturing method.

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