Contact structure of solar cell, method for preparing the same, and solar cell

Abstract

The present application provides a contact structure of a solar cell, a preparation method thereof, and a solar cell. The contact structure includes a sequentially stacked semiconductor substrate, a first passivation contact structure, and a second passivation contact structure, wherein the first passivation contact structure includes a first doping layer, a passivation layer, and a second doping layer, the passivation layer has a plurality of first through holes, the first through holes are filled with a first filling portion, and the second passivation contact structure includes a third doping layer, the second doping layer and the third doping layer have opposite polarities, that is, the contact structure of the solar cell has both the second doping layer and the third doping layer doping type, therefore, the contact structure of the solar cell has two opposite doping types, which solves the problem that the passivation contact structure in the related art is only of a single polarity and cannot meet the use of more types of solar cells.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to a contact structure of a solar cell, a preparation method thereof, a solar cell and a stacked cell. Background Art

[0002] TOPcon is a tunnel oxide passivated contact (TOPcon) solar technology based on the principle of selective carriers. In the prior art, TOPCon solar cells usually have a passivation contact structure, and the passivation contact structure has a single polarity, for example, the passivation contact structure only has p-type doping, or only has n-type doping. The passivation contact structure with only a single polarity can easily lead to a relatively single use scenario for solar cells, which cannot meet the needs of more types of high-efficiency battery technologies. Summary of the invention

[0003] The present application provides a contact structure of a solar cell, a preparation method thereof, a solar cell and a stacked cell, so as to solve the problem that the passivation contact structure in the related art cannot meet the needs of more types of solar cells.

[0004] According to one aspect of the present application, a contact structure of a solar cell is provided, comprising a sequentially stacked semiconductor substrate, a first passivation contact structure, and a second passivation contact structure, wherein: the first passivation contact structure comprises a stacked first doping layer and a second doping layer, the first doping layer is located on the surface of the semiconductor substrate, the first doping layer and the second doping layer have the same polarity, the first passivation contact structure also comprises a passivation layer located between the first doping layer and the second doping layer, the passivation layer has a plurality of first through holes, and the first through holes are filled with a first filling portion; the second passivation contact structure comprises a third doping layer, and the second doping layer and the third doping layer have opposite polarity.

[0005] Optionally, the material of the first filling portion includes: a material for forming the first doping layer and / or a material of the second doping layer filled in the first through hole.

[0006] Optionally, the third doping layer is formed by doping a semiconductor layer with a first dopant, and the second doping layer contains a doping element in the first dopant.

[0007] Optionally, the second passivation contact structure further includes a barrier layer located between the second doping layer and the third doping layer, the barrier layer has a plurality of second through holes, and the second through holes are filled with a second filling portion.

[0008] Optionally, the material of the second filling portion includes: a material for forming the second doping layer and / or a material of the third doping layer filled in the second through hole.

[0009] Optionally, the first passivation contact structure has a first surface facing away from the semiconductor substrate, and at least one of the second passivation contact structures is located on a portion of the first surface.

[0010] Optionally, a plurality of the second passivation contact structures are spaced apart on the first surface, and the contact structure further comprises a first dielectric layer located between adjacent second passivation contact structures.

[0011] Optionally, the contact structure further includes a second dielectric layer located on a side of the second passivation contact structure away from the first passivation contact structure.

[0012] According to another aspect of the present application, a method for preparing a contact structure of a solar cell is provided, comprising the following steps: providing a semiconductor substrate and forming a first passivation contact structure on the semiconductor substrate, the first passivation contact structure comprising a stacked first doping layer and a second doping layer, the first doping layer and the second doping layer having the same polarity, the first passivation contact structure further comprising a passivation layer located between the first doping layer and the second doping layer, the passivation layer having a plurality of first through holes, the first through holes being filled with a first filling portion; forming a second passivation contact structure on the first passivation contact structure, the second passivation contact structure comprising a third doping layer, the second doping layer and the third doping layer having opposite polarity.

[0013] Optionally, the step of forming the first passivation contact structure includes: forming the passivation layer on the semiconductor substrate; forming the second doping layer on the passivation layer using a semiconductor material and a second dopant, wherein a portion of the second dopant diffuses into the semiconductor substrate through the first through hole to form the first doping layer, and a portion of the semiconductor material and a portion of the second dopant are filled in the first through hole to form the first filling portion.

[0014] Optionally, the steps of forming the first doping layer and the second doping layer include: depositing a first intrinsic semiconductor material above the passivation layer, part of the first intrinsic semiconductor material is filled in the first through hole, and the remaining first intrinsic semiconductor material is located on the side of the passivation layer away from the first doping layer; depositing a second dopant on the surface of the first intrinsic semiconductor material and performing annealing treatment, a part of the doping elements in the second dopant diffuses into the first intrinsic semiconductor material to form the first intrinsic semiconductor material located on the passivation layer into the second doping layer, and another part of the doping elements in the second dopant diffuses into the substrate through the first through hole to form part of the substrate into the first doping layer.

[0015] Optionally, the steps of forming the first doped layer and the second doped layer include: depositing a first doped semiconductor material above the passivation layer, part of the first doped semiconductor material filling the first through hole, and the remaining first doped semiconductor material being located on a side of the passivation layer away from the first doped layer, and the first doped semiconductor material being formed by doping the semiconductor material with the second dopant; annealing the first doped semiconductor material so that part of the doping elements in the second dopant diffuses into the substrate through the first through hole, so as to form part of the substrate into the first doped layer, and the first doped semiconductor material located on the passivation layer forms the second doped layer.

[0016] Optionally, the step of forming the second passivation contact structure includes: forming a barrier layer on the second doping layer, the barrier layer having a plurality of second through holes; forming the third doping layer on the barrier layer, and forming a second filling portion in the second through holes.

[0017] Optionally, the step of forming the third doped layer includes: depositing a second intrinsic semiconductor material above the barrier layer, part of the second intrinsic semiconductor material is filled in the second through hole, and the remaining second intrinsic semiconductor material is located on the side of the barrier layer away from the second doped layer; depositing a first dopant on the surface of the second intrinsic semiconductor material and performing annealing, a part of the doping elements in the first dopant diffuses into the second intrinsic semiconductor material to form the third doped layer with the second intrinsic semiconductor material located on the barrier layer, and another part of the doping elements diffuses into the second through hole.

[0018] Optionally, the step of forming the third doped layer includes: depositing a second doped semiconductor material above the barrier layer, part of the second doped semiconductor material filling the second through hole, and the remaining second doped semiconductor material being located on a side of the barrier layer away from the second doped layer, the second doped semiconductor material being formed by doping a semiconductor material with a first dopant; annealing the second doped semiconductor material so that part of the doping elements in the first dopant diffuses into the second through hole, and the second doped semiconductor material located on the barrier layer forms the third doped layer.

[0019] According to another aspect of the present application, a solar cell is provided, comprising the contact structure, or comprising the contact structure prepared by the preparation method.

[0020] According to another aspect of the present application, a stacked cell is provided, comprising a bottom cell and a top cell, wherein the bottom cell is the solar cell, and the top cell is located on a side of the second passivation contact structure in the solar cell away from the first passivation contact structure.

[0021] Optionally, the band gap of the top cell is larger than the band gap of the semiconductor substrate in the solar cell.

[0022] Optionally, the top cell includes one or more combinations of perovskite cells, gallium arsenide cells, copper indium gallium selenide cells, cadmium telluride cells, amorphous silicon cells, and organic solar cells.

[0023] Through the technical solution of the present application, a contact structure of a solar cell is provided, comprising a sequentially stacked semiconductor substrate, a first passivation contact structure and a second passivation contact structure, wherein the first passivation contact structure comprises a first doped layer, a passivation layer and a second doped layer, and the second passivation contact structure comprises a third doped layer, and the second doped layer has opposite polarity to the third doped layer, that is, the contact structure of the solar cell has two opposite doping types in the second doped layer and the third doped layer. Therefore, the polarity reversal (such as p to n, or n to p) can be achieved through the above-mentioned contact structure, thereby achieving a change in the carrier transport characteristics in the contact structure, so that the solar cell with the contact structure can achieve electrical characteristics that cannot be achieved under the original polarity, thereby solving the problem that the passivation contact structure in the related art is only of a single polarity, resulting in the inability to meet the needs of more types of solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0025] Figure 1is a schematic cross-sectional structure diagram of a contact structure of a solar cell provided according to an embodiment of the present application;

[0026] Figure 2 is a schematic cross-sectional structure diagram of another contact structure of a solar cell provided according to an embodiment of the present application;

[0027] Figure 3 is a schematic cross-sectional structure diagram of another contact structure of a solar cell provided according to an embodiment of the present application;

[0028] Figure 4 is a schematic cross-sectional structure diagram of another contact structure of a solar cell provided according to an embodiment of the present application;

[0029] Figure 5 is a schematic cross-sectional structure diagram of another contact structure of a solar cell provided according to an embodiment of the present application;

[0030] Figure 6 It is a schematic flow chart of a method for preparing a contact structure of a solar cell provided in an embodiment of the present application;

[0031] Figure 7 It is a schematic diagram of a cross-sectional structure of a substrate after a passivation layer is formed on a semiconductor substrate in a method for preparing a contact structure of a solar cell provided in an embodiment of the present application;

[0032] Figure 8 is Figure 7 A schematic diagram of a cross-sectional structure of a substrate after a second doping layer is formed on the passivation layer formed in the embodiment of the present invention;

[0033] Fig. 9 is Figure 8 A schematic diagram of a cross-sectional structure of a substrate after a barrier layer is formed on the second doping layer formed in the embodiment;

[0034] Fig.10 is Fig. 9 Schematic diagram of the cross-section of the substrate structure after the third doping layer is formed on the barrier layer formed in FIG.

[0035] The above drawings include the following reference numerals:

[0036] 10. Semiconductor substrate; 20. First passivation contact structure; 21. First doped layer; 22. Second doped layer; 23. Passivation layer; 24. First through hole; 25. First filling portion; 30. Second passivation contact structure; 31. Third doped layer; 32. Barrier layer; 33. Second through hole; 34. Second filling portion; 40. First dielectric layer; 50. Second dielectric layer; 51. Opening; 60. Electrode layer. DETAILED DESCRIPTION

[0037] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0038] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0039] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so as to describe the embodiments of the present application described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0040] In the prior art, TOPCon solar cells usually have a passivation contact structure, and the passivation contact structure has a single polarity, for example, the passivation contact structure has only p-type doping, or only n-type doping. The passivation contact structure with only a single polarity can easily lead to a relatively single use scenario of the solar cell, and cannot meet the needs of more types of high-efficiency battery technology.

[0041] Therefore, research on the above issues is carried out. Figure 1 As shown, in an embodiment of the present application, a contact structure of a solar cell is provided, comprising a sequentially stacked semiconductor substrate 10, a first passivation contact structure 20 and a second passivation contact structure 30, wherein; the first passivation contact structure 20 comprises a stacked first doping layer 21 and a second doping layer 22, the first doping layer 21 is located on the surface of the semiconductor substrate 10, the first doping layer 21 and the second doping layer 22 have the same polarity, the first passivation contact structure 20 also comprises a passivation layer 23 located between the first doping layer 21 and the second doping layer 22, the passivation layer 23 has a plurality of first through holes 24, and the first through holes 24 are filled with a first filling portion 25; the second passivation contact structure 30 comprises a third doping layer 31, and the second doping layer 22 and the third doping layer 31 have opposite polarities.

[0042] By setting two opposite doping types in the second doping layer and the third doping layer in the above-mentioned contact structure, the polarity reversal (such as p to n, or n to p) can be achieved through the above-mentioned contact structure, thereby achieving a change in the carrier transport characteristics in the contact structure, so that the solar cell with the contact structure can achieve electrical characteristics that cannot be achieved under the original polarity, solving the problem in the related art that the passivation contact structure has only a single polarity, resulting in the inability to meet the needs of more types of solar cells.

[0043] In the above embodiment, if Figure 1 As shown, the contact structure has two layers, namely, the first passivation contact structure 20 and the second passivation contact structure 30. Compared with the conventional technology in which the solar cell has only one contact structure, the first passivation contact structure 20 and the second passivation contact structure 30 of the present application can reduce electron recombination and reflection losses, provide better electron transmission and diffusion performance, and can also make the solar cell respond to a wider spectrum, thereby improving the photoelectric conversion efficiency and stability of the solar cell. Through the design of the first passivation contact structure 20 and the second passivation contact structure 30, the performance of the solar cell can be improved without increasing the manufacturing cost, thereby reducing the overall production cost.

[0044] In the above embodiment, if Figure 1 As shown, the first passivation contact structure 20 includes a second doping layer 22, and the second passivation contact structure 30 includes a third doping layer 31. The second doping layer 22 and the third doping layer 31 have opposite doping polarities, which can meet the requirements of more types of solar cells for contact structures and have a wider range of applications. The doping type of the second doping layer 22 can be N-type, and the doping type of the third doping layer 31 can be P-type, or the doping type of the second doping layer 22 can be P-type, and the doping type of the third doping layer 31 can be N-type. The material of the passivation layer 23 can be silicon or silicon dioxide, which is not specifically limited in this application.

[0045] In some optional embodiments, the material of the first filling portion includes: a material for forming the first doping layer and / or a material of the second doping layer filled in the first through hole.

[0046] In the above optional embodiment, there is a passivation layer between the above-mentioned first doping layer and the second doping layer, the passivation layer has a plurality of first through holes, the first through holes are filled with a first filling portion, the lower side of the first filling portion is the first doping layer, and the upper side is the second doping layer. The filling material in the first filling portion can be the forming material of the first doping layer, can also be the forming material of the second doping layer, or can also be a mixture of the forming material of the first doping layer and the forming material of the second doping layer, and the present application does not make specific limitations.

[0047] In the above optional embodiment, the doping material of the first doping layer can be single crystal silicon, and the doping materials of the second doping layer and the third doping layer can be any one or more of amorphous silicon, nanocrystalline silicon, microcrystalline silicon, polycrystalline silicon, silicon carbide and nanocrystalline silicon oxide, which is not specifically limited in this application.

[0048] In some optional embodiments, the third doping layer is formed by doping the semiconductor layer with the first dopant, and the second doping layer contains the doping element in the first dopant.

[0049] In the above optional embodiment, the semiconductor layer is doped with a first dopant to form a third doping layer, wherein the first dopant penetrates downward into the second doping layer so that the second doping layer has doping ions of the first dopant, and further the second doping layer has doping ions of two doping types; the above first dopant may be any one or more of PCl3, AsCl3 and SbCl3, or the first dopant may be any one or more of BCl3, BBr3 and B2H6, and the semiconductor layer may be any one or more of silicon dioxide, silicon nitride and silicon. The present application does not specifically limit the types of the first dopant and the semiconductor layer.

[0050] In some optional embodiments, such as Figure 2 As shown, the second passivation contact structure 30 further includes a barrier layer 32 located between the second doping layer 22 and the third doping layer 31 . The barrier layer 32 has a plurality of second through holes 33 . The second through holes 33 are filled with second filling portions 34 .

[0051] In the above optional implementation, if Figure 2 As shown, there is a barrier layer 32 between the second doping layer 22 and the third doping layer 31 , and a second through hole 33 is provided in the barrier layer 32 . The second through hole 33 is filled with a filling material to form a second filling portion 34 .

[0052] In some optional embodiments, the material of the second filling portion includes: a material for forming the second doping layer and / or a material of the third doping layer filled in the second through hole.

[0053] In the above optional embodiment, there is a barrier layer between the third doping layer and the second doping layer, the barrier layer has a plurality of second through holes, the second through holes are filled with a second filling portion, the lower side of the second filling portion is the second doping layer, and the upper side is the third doping layer. The filling material in the second filling portion can be the forming material of the second doping layer, can also be the forming material of the third doping layer, or can also be a mixture of the forming material of the third doping layer and the forming material of the second doping layer, and the present application does not make specific limitations.

[0054] In some optional embodiments, such as Figure 3 As shown, the first passivation contact structure 20 has a first surface facing away from the semiconductor substrate 10 , and at least one second passivation contact structure 30 is located on a portion of the first surface.

[0055] In the above optional implementation, if Figure 3 As shown, the second passivation contact structure 30 may also be multiple and distributed on the first surface of the first passivation contact structure 20 .

[0056] In some optional embodiments, such as Figure 3 As shown, a plurality of the second passivation contact structures 30 are spaced apart on the first surface of the first passivation contact structure 20 , and the contact structure further includes a first dielectric layer 40 located between adjacent second passivation contact structures 30 .

[0057] In the above optional implementation, if Figure 3 As shown, the first dielectric layer 40 is arranged on the first passivation contact structure 20 at intervals, and the second passivation contact structure 30 is arranged between adjacent first dielectric layers 40. The first dielectric layer 40 can suppress the charge recombination phenomenon of the solar cell during the photoelectric conversion process, thereby improving the stability and photoelectric conversion efficiency of the solar cell. The material of the first dielectric layer 40 can be any one or more of aluminum oxide, silicon dioxide, silicon carbide, amorphous silicon, silicon nitride and silicon oxynitride, which is not specifically limited in this application. The above-mentioned solar cell with the first dielectric layer 40 can be used as the bottom cell of the stacked cell.

[0058] In the above optional implementation, if Figure 4 As shown, an electrode layer 60 may be further formed on the second passivation contact structure 30 , and the formed solar cell may be used independently. Figure 4 The first dielectric layer 40 in Figure 3 The same, without specific limitation.

[0059] In some optional embodiments, such as Figure 2 As shown, the contact structure further includes a second dielectric layer 50 located on a side of the second passivation contact structure 30 away from the first passivation contact structure 20 .

[0060] In the above optional implementation, if Figure 2As shown, the second dielectric layer 50 has one or more openings 51, which facilitates the subsequent electrical connection of the second passivation contact structure 30 with the electrode layer. The second dielectric layer 50 on the second passivation contact structure 30 can suppress the charge recombination phenomenon of the solar cell during the photoelectric conversion process, thereby improving the stability and photoelectric conversion efficiency of the solar cell. The material of the second dielectric layer 50 can be any one or more of aluminum oxide, silicon dioxide, silicon nitride, silicon oxynitride and silicon carbide, which is not specifically limited in this application. The solar cell with the second dielectric layer 50 can be used as the bottom cell of the stacked cell.

[0061] In the above optional implementation, if Figure 5 As shown, the electrode layer 60 may be formed on the second passivation contact structure 30 without forming the second dielectric layer, and the formed solar cell may be used independently. Figure 5 The structures of the third doping layer 31, the barrier layer 32, the second through hole 33 and the second filling portion 34 are similar to those of Figure 2 The present application will not repeat the description.

[0062] The present application also provides a method for preparing a contact structure of a solar cell. Figure 6 As shown, the following steps are included:

[0063] Step S1: providing a semiconductor substrate and forming a first passivation contact structure on the semiconductor substrate, wherein the first passivation contact structure comprises a stacked first doping layer and a second doping layer, wherein the first doping layer and the second doping layer have the same polarity, and the first passivation contact structure further comprises a passivation layer located between the first doping layer and the second doping layer, wherein the passivation layer has a plurality of first through holes, and wherein the first through holes are filled with a first filling portion;

[0064] Step S2: forming a second passivation contact structure on the first passivation contact structure, wherein the second passivation contact structure comprises a third doping layer, and the second doping layer has a polarity opposite to that of the third doping layer.

[0065] By using the above-mentioned method for preparing the contact structure of a solar cell of the present application, a second doping layer is prepared in the first passivation contact structure, and a third doping layer is prepared in the second passivation contact structure, wherein the second doping layer and the third doping layer have different doping polarities. Therefore, the contact structure of the solar cell prepared by the above-mentioned preparation method has two opposite doping types, which solves the problem in the related art that the passivation contact structure has only a single polarity and cannot meet the needs of being used by more types of solar cells.

[0066] The following is a more detailed description of exemplary embodiments of the method for preparing the contact structure of the solar cell provided by the present application. However, these exemplary embodiments can be implemented in a variety of different forms and should not be interpreted as being limited to the embodiments described herein. It should be understood that these embodiments are provided to make the disclosure of the present application thorough and complete, and to fully convey the concepts of these exemplary embodiments to those of ordinary skill in the art.

[0067] First, if Figure 7 and Figure 8 As shown, step S1 is performed: a first passivation contact structure 20 is formed on the semiconductor substrate 10, the first passivation contact structure 20 includes a stacked first doping layer 21 and a second doping layer 22, the first doping layer 21 and the second doping layer 22 have the same polarity, the first passivation contact structure 20 also includes a passivation layer 23 located between the first doping layer 21 and the second doping layer 22, the passivation layer 23 has a plurality of first through holes 24, and the first through holes 24 are filled with a first filling portion 25.

[0068] Specifically, a semiconductor substrate 10 is provided, and the semiconductor substrate 10 can be any one of single crystal silicon, polycrystalline silicon and silicon, which is not specifically limited in the present application; a first doping layer 21, a second doping layer 22 and a passivation layer 23 are formed on the provided semiconductor substrate 10 to obtain a first passivation contact structure 20, and the passivation layer 23 has a first through hole 24, and the first through hole 24 is filled with a first filling portion 25, wherein the first doping layer 21 and the second doping layer 22 have the same doping polarity, and the first doping layer 21 and the second doping layer 22 can be P-type or N-type.

[0069] In some optional embodiments, such as Figure 7 and Figure 8 As shown, the steps of forming the above-mentioned first passivation contact structure 20 include: forming the above-mentioned passivation layer 23 on the above-mentioned semiconductor substrate 10; using semiconductor material and second dopant to form the above-mentioned second doping layer 22 on the above-mentioned passivation layer 23, wherein part of the above-mentioned second dopant diffuses into the above-mentioned semiconductor substrate 10 through the above-mentioned first through hole 24 to form the above-mentioned first doping layer 21, and part of the above-mentioned semiconductor material and part of the above-mentioned second dopant are filled in the above-mentioned first through hole 24 to form the above-mentioned first filling part 25.

[0070] In the above optional implementation, if Figure 7 As shown, the above-mentioned passivation layer 23 is first formed on the semiconductor substrate 10, and a plurality of first through holes 24 are provided in the passivation layer 23, wherein the material of the passivation layer 23 can be any one or more of aluminum oxide, silicon oxide, silicon carbide, silicon nitride, silicon oxynitride and amorphous silicon, which is not specifically limited in the present application.

[0071] In the above optional implementation, if Figure 8 As shown, the second dopant and the semiconductor material are placed on the surface of the passivation layer 23, and part of the second dopant and the semiconductor material will penetrate into the semiconductor substrate 10 through the first through hole 24 to form a first doping layer 21. The second dopant and the semiconductor material located on the surface of the passivation layer 23 form a second doping layer 22, and the second dopant and the semiconductor material placed in the first through hole 24 form a first filling portion 25.

[0072] In some optional embodiments, the steps of forming the above-mentioned first doped layer and the above-mentioned second doped layer include: depositing a first intrinsic semiconductor material above the above-mentioned barrier layer, part of the above-mentioned first intrinsic semiconductor material is filled in the above-mentioned first through hole, and the remaining above-mentioned first intrinsic semiconductor material is located on the side of the above-mentioned passivation layer away from the above-mentioned first doped layer; depositing a second dopant on the surface of the above-mentioned first intrinsic semiconductor material and performing annealing treatment, a part of the doping elements in the above-mentioned second dopant is diffused into the first intrinsic semiconductor material to form the above-mentioned second doped layer with the above-mentioned first intrinsic semiconductor material located on the above-mentioned passivation layer, and another part of the doping elements in the above-mentioned second dopant is diffused into the above-mentioned substrate through the above-mentioned first through hole to form the above-mentioned first doped layer with part of the above-mentioned substrate.

[0073] In the above optional embodiment, in the process of forming the first doping layer and the above second doping layer, a first intrinsic semiconductor material can be first deposited on the barrier layer, part of the first intrinsic semiconductor material will fill the first through hole, and the second dopant is deposited on the first intrinsic semiconductor material. The second dopant will penetrate downward along the first intrinsic semiconductor material, part of the second dopant is located in the first intrinsic semiconductor material, and part of the second dopant will penetrate into the semiconductor substrate through the first through hole. The first intrinsic semiconductor material and the second dopant are annealed to make the first intrinsic semiconductor material and the second dopant located therein form a second doping layer, and the second dopant located in the semiconductor substrate forms a first doping layer.

[0074] In some optional embodiments, the steps of forming the above-mentioned first doped layer and the above-mentioned second doped layer include: depositing a first doped semiconductor material above the above-mentioned barrier layer, part of the above-mentioned first doped semiconductor material is filled in the above-mentioned first through hole, and the remaining above-mentioned first doped semiconductor material is located on the side of the above-mentioned passivation layer away from the above-mentioned first doped layer, and the above-mentioned first doped semiconductor material is formed by doping the above-mentioned semiconductor material with the above-mentioned second dopant; annealing the above-mentioned first doped semiconductor material so that part of the doping elements in the above-mentioned second dopant diffuses into the above-mentioned substrate through the above-mentioned first through hole, so as to form the above-mentioned first doped layer with part of the above-mentioned substrate, and the above-mentioned first doped semiconductor material located on the above-mentioned passivation layer forms the above-mentioned second doped layer.

[0075] In the above optional implementation, in the process of forming the first doped layer and the above second doped layer, a first doped semiconductor material may be first deposited on the barrier layer, part of the first doped semiconductor material may be filled in the first through hole, and the first doped semiconductor material is a mixed material of the second dopant and the above semiconductor material. The first doped semiconductor material may penetrate into the semiconductor substrate through the first through hole, and the first doped semiconductor material may be annealed so that the first doped semiconductor material on the passivation layer forms the second doped layer, and the first doped semiconductor material in the semiconductor substrate forms the first doped layer.

[0076] In the above optional implementation manner, the above deposition method may be any one of an in-situ deposition method, a chemical vapor deposition method and a physical vapor deposition method, and the present application does not make any specific limitation thereto.

[0077] After the step of forming the first passivation contact structure on the semiconductor substrate, Fig. 9 and Fig.10 As shown, step S2 is performed: forming a second passivation contact structure 30 on the first passivation contact structure 20 , wherein the second passivation contact structure 30 includes a third doping layer 31 , and the second doping layer 22 has opposite polarity to the third doping layer 31 .

[0078] Specifically, a third doping layer 31 of the second passivation contact structure 30 is formed on the first passivation contact structure 20, and the second doping layer 22 has an opposite polarity to the third doping layer 31, so that the solar cell has a contact structure with different doping types, which expands the range of use scenarios of the solar cell and increases the types of solar cells using the above contact structure.

[0079] In some optional embodiments, such as Fig. 9 and Fig.10 As shown, the steps of forming the second passivation contact structure 30 include: forming a barrier layer 32 on the second doping layer 22, wherein the barrier layer 32 has a plurality of second through holes 33; forming the third doping layer 31 on the barrier layer 32, and forming a second filling portion 34 in the second through holes 33.

[0080] In the above optional implementation, if Fig. 9 As shown, the barrier layer 32 is first formed on the second doping layer 22, and the barrier layer 32 has a plurality of second through holes 33, wherein the material of the barrier layer 32 can be any one or more of aluminum oxide, silicon oxide, silicon carbide, silicon nitride, silicon oxynitride and amorphous silicon, which is not specifically limited in this application. Fig.10As shown, a third doping layer 31 is formed on the barrier layer 32, and the material for preparing the third doping layer 31 penetrates into the second doping layer 22 during the preparation process or through the second through hole 33, and part of the material of the third doping layer remains in the second through hole 33, serving as at least part of the second filling portion 34. It should be noted that in the process of the material of the third doping layer penetrating downward into the second doping layer 22 through the second through hole 33, part of the material in the second doping layer 22 will also diffuse upward into the third doping layer through the second through hole 33.

[0081] In some optional embodiments, the step of forming the above-mentioned third doping layer includes: depositing a second intrinsic semiconductor material above the above-mentioned barrier layer, part of the above-mentioned second intrinsic semiconductor material is filled in the above-mentioned second through hole, and the remaining above-mentioned second intrinsic semiconductor material is located on the side of the above-mentioned barrier layer away from the above-mentioned second doping layer; depositing a first dopant on the surface of the above-mentioned second intrinsic semiconductor material and performing annealing treatment, a part of the doping elements in the above-mentioned first dopant is diffused into the second intrinsic semiconductor material, so as to form the above-mentioned third doping layer with the above-mentioned second intrinsic semiconductor material located on the above-mentioned barrier layer, and another part of the above-mentioned doping elements is diffused into the above-mentioned second through hole.

[0082] In the above optional embodiment, in the process of forming the third doping layer, a second intrinsic semiconductor material may be first deposited on the barrier layer, part of the second intrinsic semiconductor material may be filled in the second through hole, a first dopant may be deposited on the second intrinsic semiconductor material, the first dopant may penetrate downward along the second intrinsic semiconductor material, part of the first dopant may be located in the second intrinsic semiconductor material, another part of the first dopant may penetrate into the second doping layer through the second through hole, the second intrinsic semiconductor material and the first dopant may be annealed so that the second intrinsic semiconductor material and the first dopant located therein may form a third doping layer, the first dopant located in the second doping layer may form a part of the second doping layer, and at this time, the second doping layer may contain both the first dopant and the second dopant. In addition, in the process of the first dopant penetrating downward into the second doping layer through the second through hole, the second dopant in the second doping layer may also diffuse upward into the third doping layer through the second through hole.

[0083] In the above optional implementation manner, the above deposition method may be any one of an in-situ deposition method, a chemical vapor deposition method and a physical vapor deposition method, and the present application does not make any specific limitation thereto.

[0084] In some optional embodiments, the step of forming the third doped layer includes: depositing a second doped semiconductor material above the barrier layer, part of the second doped semiconductor material filling the second through hole, and the remaining second doped semiconductor material being located on the side of the barrier layer away from the second doped layer, and the second doped semiconductor material being formed by doping the semiconductor material with a first dopant; annealing the second doped semiconductor material so that part of the doping elements in the first dopant diffuses into the second through hole, and the second doped semiconductor material located on the barrier layer forms the third doped layer.

[0085] In the above optional implementation, in the process of forming the third doped layer, a second doped semiconductor material may be first deposited on the barrier layer, and part of the second doped semiconductor material may be filled in the second through hole, and the second doped semiconductor material is a mixed material of the first dopant and the above semiconductor material. The second doped semiconductor material may penetrate into the semiconductor substrate through the second through hole, and the second doped semiconductor material may be annealed so that the second doped semiconductor material on the passivation layer forms the third doped layer, and the second doped semiconductor material in the second doped layer forms a part of the second doped layer, and at this time, the second doped layer contains both the first dopant and the second dopant. In addition, in the process of the second doped semiconductor material penetrating downward into the second doped layer through the second through hole, the second dopant in the second doped layer may also diffuse upward into the third doped layer through the second through hole.

[0086] Figures 2 to 5 and Figures 9 and 10 The first passivation contact structure 20, the first doping layer 21, the second doping layer 22, the passivation layer 23, the first through hole 24 and the first filling portion 25 are all connected to Figure 1 According to another embodiment of the present application, a solar cell is provided, comprising the contact structure described above, or comprising a contact structure prepared by the preparation method described above.

[0087] The solar cell prepared by the method for preparing the contact structure of a solar cell of the present application, or having the above-mentioned contact structure, has two opposite doping types, which solves the problem that the passivation contact structure in the related art has only a single polarity and cannot meet the needs of being used by more types of solar cells.

[0088] According to another embodiment of the present application, a stacked cell is provided, including a bottom cell and a top cell, wherein the bottom cell is the solar cell, and the top cell is located on a side of the second passivation contact structure in the solar cell away from the first passivation contact structure.

[0089] The stacked battery using the solar cell of the present application as the bottom cell has a contact structure with two opposite doping types, which solves the problem in the related art that the passivation contact structure has only a single polarity and cannot meet the needs of being used by more types of solar cells, thereby expanding the use scenarios of the stacked battery.

[0090] In some optional embodiments, the band gap of the top cell is greater than the band gap of the semiconductor substrate in the solar cell.

[0091] In the above optional implementation, when the band gap of the top cell is larger than the band gap of the semiconductor substrate of the bottom cell, the top cell can absorb a shorter wavelength spectrum and the bottom cell can absorb a longer wavelength spectrum, thereby improving the utilization of the spectrum and the conversion efficiency of the entire stacked cell to solar energy. The top cell and the bottom cell absorb spectra of different wavelengths respectively, and the photocurrents of the two can be superimposed together, thereby increasing the total photocurrent output of the entire stacked cell. The top cell and the bottom cell absorb spectra of different wavelengths respectively, which can reduce heat loss caused by excess spectrum and improve the thermal efficiency of the stacked cell.

[0092] In some optional embodiments, the top cell includes one or more combinations of perovskite cells, gallium arsenide cells, copper indium gallium selenide cells, cadmium telluride cells, amorphous silicon cells, and organic solar cells.

[0093] In the above optional implementation manner, those skilled in the art may arbitrarily select the type of the top battery of the stacked battery in actual situations, and this application does not make any specific limitation.

[0094] The contact structure of the solar cell and the preparation method thereof in the present application will be specifically described below in conjunction with embodiments.

[0095] Example 1

[0096] This embodiment provides a method for preparing a contact structure of a solar cell, comprising the following steps:

[0097] Providing a semiconductor substrate, wherein the material of the semiconductor substrate is silicon and the thickness is 30 μm;

[0098] A passivation layer is formed on a semiconductor substrate, wherein the material of the passivation layer is silicon dioxide and the thickness is 10 μm;

[0099] Depositing a first intrinsic semiconductor material on the passivation layer, wherein the first intrinsic semiconductor material is silicon and has a thickness of 20 μm after deposition, wherein a portion of the first intrinsic semiconductor material is filled in the first through hole, and the remaining first intrinsic semiconductor material is located on a side of the passivation layer away from the first doping layer;

[0100] A second dopant is deposited on the surface of the first intrinsic semiconductor material and annealed, wherein the material of the second dopant is BCl3 and the thickness after deposition is 10 μm, a portion of the doping elements in the second dopant is diffused into the first intrinsic semiconductor material to form a second doping layer with the first intrinsic semiconductor material on the passivation layer, and another portion of the doping elements in the second dopant is diffused into the substrate through the first through hole to form a first doping layer with a portion of the substrate;

[0101] Depositing a second intrinsic semiconductor material on the barrier layer, the second intrinsic semiconductor material is silicon, and the thickness after deposition is 20 μm, a portion of the second intrinsic semiconductor material is filled in the second through hole, and the remaining second intrinsic semiconductor material is located on a side of the barrier layer away from the second doping layer;

[0102] A first dopant is deposited on the surface of the second intrinsic semiconductor material and annealed, wherein the material of the first dopant is PCl3 and the thickness after deposition is 10 μm, a portion of the doping elements in the first dopant is diffused into the second intrinsic semiconductor material to form a third doping layer with the second intrinsic semiconductor material on the barrier layer, and another portion of the doping elements is diffused into the second through hole to form a second filling portion;

[0103] An electrode layer is formed on the third doping layer. The material of the electrode layer is Ag and the thickness is 20 μm.

[0104] Example 2

[0105] This embodiment provides a method for preparing a contact structure of a solar cell, comprising the following steps:

[0106] Providing a semiconductor substrate, wherein the material of the semiconductor substrate is silicon and the thickness is 30 μm;

[0107] A passivation layer is formed on a semiconductor substrate, wherein the material of the passivation layer is silicon dioxide and the thickness is 10 μm;

[0108] Depositing a first doped semiconductor material on the passivation layer and annealing the material so that part of the doping element in the second dopant diffuses into the substrate through the first through hole, so that part of the substrate forms a first doped layer, and the first doped semiconductor material on the passivation layer forms a second doped layer;

[0109] Depositing a second doped semiconductor material on the barrier layer, wherein the second doped semiconductor material is made of silicon and PCl3, and has a thickness of 30 μm after deposition, wherein a portion of the second doped semiconductor material is filled in the second through hole, and the remaining second doped semiconductor material is located on a side of the barrier layer away from the second doped layer, and the second doped semiconductor material is formed by doping the semiconductor material with the first dopant;

[0110] Annealing the second doped semiconductor material so that part of the doping element in the first dopant diffuses into the second through hole, and the second doped semiconductor material on the barrier layer forms a third doped layer;

[0111] An electrode layer is formed on the third doping layer. The material of the electrode layer is Ag and the thickness is 20 μm.

[0112] Example 3

[0113] This embodiment provides a method for preparing a contact structure of a solar cell, comprising the following steps:

[0114] Providing a semiconductor substrate, wherein the material of the semiconductor substrate is silicon and the thickness is 30 μm;

[0115] A passivation layer is formed on a semiconductor substrate, wherein the material of the passivation layer is silicon dioxide and the thickness is 10 μm;

[0116] Depositing a first doped semiconductor material on the passivation layer and annealing the first doped semiconductor material, wherein the first doped semiconductor material is made of silicon and BCl3 and has a thickness of 30 μm after deposition, so that part of the doping element in the second dopant diffuses into the substrate through the first through hole, so that part of the substrate forms a first doped layer, and the first doped semiconductor material on the passivation layer forms a second doped layer;

[0117] Depositing a second intrinsic semiconductor material on the barrier layer, the second intrinsic semiconductor material is silicon, and the thickness after deposition is 20 μm, a portion of the second intrinsic semiconductor material is filled in the second through hole, and the remaining second intrinsic semiconductor material is located on a side of the barrier layer away from the second doping layer;

[0118] A first dopant is deposited on the surface of the second intrinsic semiconductor material and annealed, wherein the material of the first dopant is PCl3 and the thickness after deposition is 10 μm, a portion of the doping elements in the first dopant is diffused into the second intrinsic semiconductor material to form a third doping layer with the second intrinsic semiconductor material on the barrier layer, and another portion of the doping elements is diffused into the second through hole to form a second filling portion;

[0119] An electrode layer is formed on the third doping layer. The material of the electrode layer is Ag and the thickness is 20 μm.

[0120] Example 4

[0121] This embodiment provides a method for preparing a contact structure of a solar cell, comprising the following steps:

[0122] Providing a semiconductor substrate, wherein the material of the semiconductor substrate is silicon and the thickness is 30 μm;

[0123] A passivation layer is formed on a semiconductor substrate, wherein the material of the passivation layer is silicon dioxide and the thickness is 10 μm;

[0124] Depositing a first doped semiconductor material on the passivation layer and annealing the first doped semiconductor material, wherein the first doped semiconductor material is made of silicon and BCl3 and has a thickness of 30 μm after deposition, so that part of the doping element in the second dopant diffuses into the substrate through the first through hole, so that part of the substrate forms a first doped layer, and the first doped semiconductor material on the passivation layer forms a second doped layer;

[0125] forming a first dielectric layer on the second doped layer, wherein the material of the first dielectric layer is aluminum oxide and the thickness is 10 μm, and the first dielectric layer is distributed on the second doped layer at intervals;

[0126] Depositing a second intrinsic semiconductor material between adjacent first dielectric layers, the second intrinsic semiconductor material is silicon, and the thickness after deposition is 20 μm, a portion of the second intrinsic semiconductor material is filled in the second through hole, and the remaining second intrinsic semiconductor material is located on a side of the barrier layer away from the second doping layer;

[0127] A first dopant is deposited on the surface of the second intrinsic semiconductor material and annealed, wherein the material of the first dopant is PCl3 and the thickness after deposition is 10 μm, a portion of the doping elements in the first dopant is diffused into the second intrinsic semiconductor material to form a third doping layer with the second intrinsic semiconductor material on the barrier layer, and another portion of the doping elements is diffused into the second through hole to form a second filling portion;

[0128] An electrode layer is formed on the third doping layer. The material of the electrode layer is Ag and the thickness is 20 μm.

[0129] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0130] The contact structure of the solar cell in the embodiment of the present application is adopted. Since the second doping layer and the third doping layer have opposite polarities, that is, the contact structure of the solar cell has both the second doping layer and the third doping layer doping types. Therefore, the contact structure of the solar cell has two opposite doping types, which solves the problem in the related art that the passivation contact structure has only a single polarity and cannot meet the needs of being used by more types of solar cells.

[0131] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0132] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A contact structure of a solar cell, characterized in that: It comprises a semiconductor substrate, a first passivation contact structure and a second passivation contact structure which are sequentially stacked, wherein; The first passivation contact structure includes a stacked first doping layer and a second doping layer, the first doping layer is located on the surface of the semiconductor substrate, the first doping layer and the second doping layer have the same polarity, the first passivation contact structure also includes a passivation layer located between the first doping layer and the second doping layer, the passivation layer has a plurality of first through holes, and the first through holes are filled with a first filling portion; The second passivation contact structure includes a third doping layer, and the second doping layer has a polarity opposite to that of the third doping layer.

2. The contact structure according to claim 1, characterized in that: The material of the first filling portion includes: a material for forming the first doping layer and / or a material of the second doping layer filled in the first through hole.

3. The contact structure according to claim 1, characterized in that: The third doping layer is formed by doping the semiconductor layer with a first dopant, and the second doping layer contains the doping element in the first dopant.

4. The contact structure according to claim 1, characterized in that: The second passivation contact structure further includes a barrier layer located between the second doping layer and the third doping layer, the barrier layer has a plurality of second through holes, and the second through holes are filled with a second filling portion.

5. The contact structure according to claim 4, characterized in that: The material of the second filling portion includes: a material for forming the second doping layer and / or a material of the third doping layer filled in the second through hole.

6. The contact structure according to any one of claims 1 to 5, characterized in that: The first passivation contact structure has a first surface facing away from the semiconductor substrate, and at least one second passivation contact structure is located on a portion of the first surface.

7. The contact structure according to claim 6, characterized in that: A plurality of the second passivation contact structures are spaced apart on the first surface, and the contact structure further comprises a first dielectric layer located between adjacent second passivation contact structures.

8. The contact structure according to any one of claims 1 to 5, characterized in that: The contact structure further includes a second dielectric layer located on a side of the second passivation contact structure facing away from the first passivation contact structure.

9. A method for preparing a contact structure of a solar cell, characterized in that: The following steps are involved: Providing a semiconductor substrate and forming a first passivation contact structure on the semiconductor substrate, wherein the first passivation contact structure comprises a stacked first doping layer and a second doping layer, wherein the first doping layer and the second doping layer have the same polarity, and the first passivation contact structure further comprises a passivation layer located between the first doping layer and the second doping layer, wherein the passivation layer has a plurality of first through holes, and wherein the first through holes are filled with a first filling portion; A second passivation contact structure is formed on the first passivation contact structure, wherein the second passivation contact structure includes a third doping layer, and the second doping layer has a polarity opposite to that of the third doping layer.

10. The preparation method according to claim 9, characterized in that: The step of forming the first passivation contact structure comprises: forming the passivation layer on the semiconductor substrate; The second doping layer is formed on the passivation layer using semiconductor material and a second dopant, wherein part of the second dopant diffuses into the semiconductor substrate through the first through hole to form the first doping layer, and part of the semiconductor material and part of the second dopant are filled in the first through hole to form the first filling portion.

11. The preparation method according to claim 10, characterized in that: The steps of forming the first doping layer and the second doping layer include: Depositing a first intrinsic semiconductor material on the passivation layer, wherein a portion of the first intrinsic semiconductor material is filled in the first through hole, and the remaining first intrinsic semiconductor material is located on a side of the passivation layer away from the first doping layer; A second dopant is deposited on the surface of the first intrinsic semiconductor material and annealed, a portion of the doping elements in the second dopant diffuses into the first intrinsic semiconductor material to form the second doping layer with the first intrinsic semiconductor material on the passivation layer, and another portion of the doping elements in the second dopant diffuses into the substrate through the first through hole to form part of the substrate into the first doping layer.

12. The preparation method according to claim 10, characterized in that: The steps of forming the first doping layer and the second doping layer include: Depositing a first doped semiconductor material on the passivation layer, wherein a portion of the first doped semiconductor material fills the first through hole, and the remaining first doped semiconductor material is located on a side of the passivation layer away from the first doped layer, and the first doped semiconductor material is formed by doping the semiconductor material with the second dopant; The first doped semiconductor material is annealed to diffuse part of the doping elements in the second dopant into the substrate through the first through hole, so that part of the substrate forms the first doped layer, and the first doped semiconductor material on the passivation layer forms the second doped layer.

13. The preparation method according to claim 9, characterized in that: The step of forming the second passivation contact structure comprises: forming a barrier layer on the second doping layer, wherein the barrier layer has a plurality of second through holes; The third doping layer is formed on the barrier layer, and a second filling portion is formed in the second through hole.

14. The preparation method according to claim 13, characterized in that: The step of forming the third doping layer comprises: Depositing a second intrinsic semiconductor material on the barrier layer, wherein a portion of the second intrinsic semiconductor material fills the second through hole, and the remaining second intrinsic semiconductor material is located on a side of the barrier layer away from the second doping layer; A first dopant is deposited on the surface of the second intrinsic semiconductor material and annealed, a portion of the doping elements in the first dopant diffuses into the second intrinsic semiconductor material to form the third doping layer from the second intrinsic semiconductor material on the barrier layer, and another portion of the doping elements diffuses into the second through hole.

15. The preparation method according to claim 13, characterized in that: The step of forming the third doping layer comprises: Depositing a second doped semiconductor material on the barrier layer, wherein a portion of the second doped semiconductor material fills the second through hole, and the remaining second doped semiconductor material is located on a side of the barrier layer away from the second doped layer, wherein the second doped semiconductor material is formed by doping a semiconductor material with a first dopant; The second doped semiconductor material is annealed to diffuse part of the doping elements in the first dopant into the second through hole, and the second doped semiconductor material on the barrier layer forms the third doped layer.

16. A solar cell, characterized in that: The invention comprises the contact structure described in any one of claims 1 to 8, or comprises the contact structure prepared by the preparation method described in any one of claims 9 to 15.

17. A laminated battery, characterized in that: The invention comprises a bottom cell and a top cell, wherein the bottom cell is the solar cell as claimed in claim 16, and the top cell is located at a side of the second passivation contact structure in the solar cell facing away from the first passivation contact structure.

18. The laminated battery according to claim 17, characterized in that: The band gap of the top cell is larger than the band gap of the semiconductor substrate in the solar cell.

19. The laminated battery according to claim 17, characterized in that: The top cell includes one or more combinations of perovskite cells, gallium arsenide cells, copper indium gallium selenide cells, cadmium telluride cells, amorphous silicon cells, and organic solar cells.

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