Solar cell and its manufacturing method, photovoltaic module

Abstract

To provide, in the technical field of solar cells, particularly a solar cell, a manufacturing method thereof, and a photovoltaic module.SOLUTION: A solar cell comprises: a substrate having a metal pattern region and a non-metal pattern region in a surface; a doped layer located inside the substrate in a first region and a second region; and a first passivation contact structure covering the substrate surface in the metal pattern region. The non-metal pattern region comprises the adjacent first and second regions. A side of the second region far from the first region is adjacent to the metal pattern region. The substrate surface in the first region is lower than the substrate surface in the metal pattern region. The substrate surface in the second region is not lower than the substrate surface in the first region and is not higher than the substrate surface in the metal pattern region. The substrate is exposed to the top surface of the doped layer. The first passivation contact structure includes at least one first tunneling layer and at least one first doped conductive layer stacked. The present application is beneficial to improve the photoelectric conversion efficiency of a solar cell.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The embodiments of the present application relate to the technical field of solar cells, and more particularly to solar cells and their manufacturing methods, and photovoltaic modules. [Background technology]

[0002] Solar cells have excellent photoelectric conversion capabilities. In solar cells, a doping layer, such as an emitter or a passivation doping layer, is formed on the surface of the substrate. The emitter can form a PN junction with the substrate, and the passivation doping layer is used to suppress carrier recombination on the substrate surface in solar cells and enhance the passivation effect on the substrate. In addition, solar cells require the fabrication of a metal electrode for carrier collection. To collect carriers, the metal electrode is usually electrically connected to the doping layer.

[0003] However, the poor contact performance between the conventional metal electrode and the doped layer causes large contact recombination loss in the metal electrode, resulting in poor photoelectric conversion performance of the solar cell. Summary of the Invention [Problem to be solved by the invention]

[0004] In the embodiments of the present application, a solar cell, a manufacturing method thereof, and a photovoltaic module are provided, which are advantageous in improving at least the photoelectric conversion efficiency of the solar cell. [Means for solving the problem]

[0005] In an embodiment of the present application, a solar cell is provided, which includes a substrate having a metal pattern region and a non-metal pattern region on its surface, a doping layer located in the substrate in the first region and the second region, and a first passivation contact structure covering the substrate surface of the metal pattern region, wherein the non-metal pattern region includes adjacent first and second regions, the side of the second region farther from the first region is adjacent to the metal pattern region, the substrate surface of the first region is lower than the substrate surface of the metal pattern region, the substrate surface of the second region is not lower than the substrate surface of the first region and not higher than the substrate surface of the metal pattern region, the substrate is exposed on the upper surface of the doping layer, and the first passivation contact structure includes at least one first tunnel layer and at least one first doped conductive layer stacked together.

[0006] The doping element of the first doped conductive layer and the doping element of the doped layer are of the same group.

[0007] The doping element concentration of the first doped conductive layer is equal to or greater than the doping element concentration of the doped layer.

[0008] The doping element concentration of the first doped conductive layer is 1×10 19 atoms / cm 3 ~9×10 20 atoms / cm 3 and the doping element concentration of the doped layer is 1×10 16 atoms / cm 3 ~1×10 20 atoms / cm 3 is.

[0009] Furthermore, the type of doping element in the doped layer is different from the type of doping element in the substrate.

[0010] The doping layer has a doping element concentration greater than that of the substrate.

[0011] Furthermore, there is a first included angle between the substrate surface in the first region and the substrate surface in the second region, and the first included angle is 90° to 160°.

[0012] In addition, the doping element concentration of the doped layer in the second region is not less than the doping element concentration of the doped layer in the first region and not greater than the doping element concentration of the first doped conductive layer.

[0013] In addition, the doping element concentration of the doped layer in the second region gradually decreases in the direction from the side of the doped layer in the first region facing the first doped conductive layer to the side of the doped layer in the first region facing away from the first doped conductive layer.

[0014] The difference between the doping concentration of the surface of the doped layer in the second region facing the first doped conductive layer and the doping concentration of the surface of the doped layer in the second region facing away from the first doped conductive layer is 1×10 19 atoms / cm 3 ~8×10 20 atoms / cm 3 is.

[0015] The doped layer has a sheet resistance of 80 ohm / sq to 1000 ohm / sq.

[0016] The difference in height between the substrate surface in the metal pattern region and the substrate surface in the first region is 0.1 μm to 10 μm.

[0017] The first passivation contact structure also includes a plurality of sub-first passivation contact structures stacked along a direction away from the substrate, and the sub-first passivation contact structures include the first tunnel layer and the first doped conductive layer stacked along a direction away from the substrate.

[0018] The semiconductor device further includes a second passivation contact structure located on a surface of the substrate farther from the first passivation contact structure, the second passivation contact structure including at least one second tunnel layer and at least one second doped conductive layer stacked together.

[0019] The semiconductor device further includes a first passivation layer located on an upper surface of the doping layer and on an upper surface and a side surface of the first passivation contact structure.

[0020] The semiconductor device further includes a first electrode, the first electrode passing through the first passivation layer and electrically connected to the first doped conductive layer.

[0021] Correspondingly, an embodiment of the present application further provides a photovoltaic module, which includes a cell string formed by connecting a plurality of solar cells described in any one of the above items, an encapsulation layer used to cover a surface of the cell string, and a cover plate used to cover a surface of the encapsulation layer remote from the battery string.

[0022] Correspondingly, an embodiment of the present application further provides a method for manufacturing a solar cell, the method for manufacturing a solar cell comprising: providing a substrate, the substrate having an initial surface, the initial surface including a metal pattern region and a non-metal pattern region; forming an initial first passivation contact structure and a dielectric layer sequentially stacked on the initial surface of the substrate along a direction away from the substrate; performing a patterning process on the dielectric layer to form a first opening in the dielectric layer, the first opening facing the non-metal pattern region; and patterning the initial first passivation contact structure along the first opening to form a substrate surface of the non-metal pattern region and a substrate surface of the metal pattern region. the substrate surface of the non-metal pattern region has adjacent first and second regions, the substrate surface of the second region is adjacent to the substrate of the metal pattern region, the substrate surface of the first region is lower than the substrate surface of the metal pattern region, and the substrate surface of the second region is neither lower than the substrate surface of the first region nor higher than the substrate surface of the metal pattern region, and the remaining initial first passivation contact structure forms the first passivation contact structure; performing a doping process on the substrate surfaces of the first region and the second region to form a doped layer in the substrate; and removing the dielectric layer.

[0023] Furthermore, performing a patterning process on the dielectric layer includes laser processing the dielectric layer in the non-metal pattern region using a laser process to remove the dielectric layer in the non-metal pattern region, forming the first opening, and exposing the initial first passivation contact structure in the non-metal pattern region through the first opening.

[0024] In addition, performing a patterning process on the dielectric layer includes forming an ink layer on the upper surface of the dielectric layer in the metal pattern area directly facing the metal pattern area, acid-washing the dielectric layer to remove the dielectric layer in the non-metal pattern area, forming the first opening, and exposing the initial first passivation contact structure in the non-metal pattern area through the first opening.

[0025] Furthermore, performing a doping process on the substrate surface in the first region and the second region includes injecting a doping element into the substrate surface in the first region and the second region so as to diffuse the doping element into the substrate in the first region and the second region and form an initial doped layer having a predetermined thickness, and performing an annealing process on the initial doped layer so as to form the doped layer.

[0026] In addition, the doping element concentration of the doping layer in the second region gradually decreases in a direction from the side of the doping layer in the first region facing the first passivation contact structure to the side of the doping layer in the first region away from the first passivation contact structure. [Effects of the Invention]

[0027] The technical solution according to the embodiments of the present application has at least the following advantages:

[0028] In the solar cell technical solution provided by the embodiments of the present application, a first passivation contact structure is installed on a substrate in a metal pattern region, and the metal pattern region is an area for forming a metal electrode, i.e., the metal electrode is in electrical contact with the first passivation contact structure, thereby reducing the contact recombination loss of the metal electrode and improving the performance of the solar cell.

[0029] In view of the problem of parasitic absorption of incident light caused by the first doped conductive layer, a doped layer is formed on the substrate in the non-metallic pattern region. The doped layer can perform functions such as selective carrier transport and forming a built-in electric field in the substrate. By using the same material for the doped layer and the substrate, the parasitic absorption of incident light by the doped layer can be significantly reduced and the utilization rate of incident light can be increased. Furthermore, the first region, second region, and metal pattern region of the non-metallic pattern region are sequentially adjacent, and the height of the substrate in the second region is set between the height of the substrate in the first region and the height of the substrate in the metal pattern region, so that the substrate surfaces in the first region, second region, and metal pattern region form a stepped structure. As a result, the upper surfaces of the doped layers formed in the substrate in the first and second regions also have a stepped structure, which increases the area of ​​the doped layer compared to a flat doped layer, advantageously increasing the active area of ​​the doped layer and improving the photoelectric conversion performance of the solar cell. [Brief explanation of the drawings]

[0030] One or more embodiments are illustratively illustrated in corresponding figures in the accompanying drawings, and these illustrative illustrations are not intended to be limiting of the embodiments, and unless otherwise specified, the figures in the accompanying drawings do not form a proportional limitation. [Figure 1] FIG. 1 is a diagram showing a cross-sectional structure of a solar cell provided according to one embodiment of the present application. [Figure 2] FIG. 2 is a diagram showing a cross-sectional structure of another solar cell provided by an embodiment of the present application. [Figure 3] FIG. 3 is a diagram showing a cross-sectional structure of another solar cell provided by an embodiment of the present application. [Figure 4] FIG. 4 is a diagram illustrating the configuration of a photovoltaic module provided by another embodiment of the present application. [Figure 5] FIG. 5 is a cross-sectional view showing a step of providing a base in a method for manufacturing a solar cell according to an embodiment of the present application. [Figure 6]FIG. 6 is a cross-sectional view illustrating a step of forming an initial first tunnel layer in a method for manufacturing a solar cell according to an embodiment of the present application. [Figure 7] FIG. 7 is a cross-sectional view illustrating a step of forming an initial first doped conductive layer in a method for manufacturing a solar cell according to an embodiment of the present invention. [Figure 8] FIG. 8 is a cross-sectional view showing a step of forming a dielectric layer in a method for manufacturing a solar cell according to an embodiment of the present invention. [Figure 9] FIG. 9 is a cross-sectional view illustrating a step of patterning a dielectric layer in a method for manufacturing a solar cell according to an embodiment of the present application. [Figure 10] FIG. 10 is a cross-sectional view illustrating a step of patterning a dielectric layer in a method for manufacturing a solar cell according to an embodiment of the present invention. [Figure 11] FIG. 11 is a cross-sectional view showing a step of patterning a dielectric layer in a method for manufacturing a solar cell according to an embodiment of the present application. [Figure 12] FIG. 12 is a cross-sectional view illustrating a step of forming a first passivation contact structure in a method for manufacturing a solar cell according to an embodiment of the present application. [Figure 13] FIG. 13 is an enlarged view of the portion enclosed by the dashed line in FIG. [Figure 14] FIG. 14 is a cross-sectional view illustrating a step of forming a first passivation contact structure in another method for manufacturing a solar cell according to an embodiment of the present application. [Figure 15] FIG. 15 is a cross-sectional view showing a step of forming a doping layer in a method for manufacturing a solar cell according to an embodiment of the present application. [Figure 16] FIG. 16 is a cross-sectional view illustrating a step of forming a second passivation contact structure in a method for manufacturing a solar cell according to an embodiment of the present application. [Figure 17] FIG. 17 is a diagram showing a cross-sectional configuration corresponding to a step of forming a first passivation layer and a second passivation layer in a method for manufacturing a solar cell according to an embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0031] As can be seen from the prior art, conventional solar cells have the problem of low photoelectric conversion efficiency.

[0032] Analysis has shown that one of the reasons for the low photoelectric conversion efficiency of conventional solar cells is their poor photoelectric conversion performance. This is because the metal pattern region requires the provision of a metal electrode, which reduces contact recombination loss at the metal electrode, and the non-metal pattern region requires the reduction of parasitic absorption of incident light to increase the absorption rate of incident light. Non-metal pattern regions typically require a doping layer to form a PN junction with the substrate or enhance carrier transport in the substrate in the non-metal pattern region. To enhance carrier transport, the doping layer in the non-metal pattern region typically requires a large area. However, creating a textured structure on the substrate surface of the non-metal pattern region can reduce the flatness of the film layer located on the substrate surface in the non-metal pattern region, which is detrimental to improving the film layer performance. In other words, the structure of conventional solar cells lacks a balance between different film layer structures, which can improve some solar cell performance while simultaneously compromising other performance. This results in poor overall photoelectric conversion performance of the solar cell.

[0033] In an embodiment of the present application, a solar cell is provided, in which a substrate surface in a non-metallic pattern region is doped, and a doped layer is formed on the substrate, the doped layer and the substrate being made of the same material, thereby significantly reducing parasitic absorption of incident light by the doped layer. A passivation contact structure is formed on the substrate in the metallic pattern region, and the passivation contact structure serves to reduce contact recombination loss of the metal electrode. The first region, the second region, and the metallic pattern region are sequentially contacted to form a step structure on the substrate surface. This allows the upper surface of the doped layer formed on the top of the substrate to also have a partial step structure, increasing the area of ​​the doped layer and further enhancing the performance of the doped layer, reducing contact recombination loss of the metal electrode while ensuring high utilization of incident light in the solar cell. This increases the active area of ​​the doped layer, thereby improving the overall photoelectric conversion performance of the solar cell.

[0034] Hereinafter, each embodiment of the present application will be described in detail with reference to the accompanying drawings. However, as will be understood by those skilled in the art, although many technical details are proposed in each embodiment of the present application to help readers better understand the present application, the technical solution claimed for protection by the present application can be realized without these technical details and various changes and modifications based on the following embodiments.

[0035] FIG. 1 is a diagram showing a cross-sectional structure of a first solar cell provided by an embodiment of the present application.

[0036] As shown in FIG. 1 , the solar cell includes a substrate 100 having a metal pattern region 10 and a non-metal pattern region 11 on its surface, a doping layer 120 located in the substrate 100 in a first region 12 and a second region 13, and a first passivation contact structure 110 covering the surface of the substrate 100 in the metal pattern region 10, the non-metal pattern region 11 including the adjacent first region 12 and second region 13, and the side of the second region 13 farther from the first region 12 adjacent to the metal pattern region 10. However, the surface of the substrate 100 in the first region 12 is lower than the surface of the substrate 100 in the metal pattern region 10, the surface of the substrate 100 in the second region 13 is not lower than the surface of the substrate 100 in the first region 12, and not higher than the surface of the substrate 100 in the metal pattern region 10, the substrate 100 is exposed on the upper surface of the doping layer 120, and the first passivation contact structure 110 includes at least one stacked first tunnel layer 111 and at least one stacked first doped conductive layer 112.

[0037] The first passivation contact structure 110 is provided only on the surface of the substrate 100 in the metal pattern region 10. In this way, providing a metal electrode in the metal pattern region 10 can reduce metal contact recombination between the first passivation contact structure 110 and the metal electrode, and improve the carrier collection ability of the metal electrode.

[0038] The doping layer 120 is disposed on the substrate 100 in the non-metallic pattern region 11, i.e., the doping layer 120 and the substrate 100 are made of the same material, which reduces the parasitic absorption ability of the substrate 100 to incident light, and also reduces the parasitic absorption ability of the doping layer 120 to incident light. Compared with disposing the first passivation contact structure 110 on the surface of the substrate 100 in the non-metallic pattern region 11, this reduces the parasitic absorption of incident light on the surface of the substrate 100 in the non-metallic pattern region 11 and improves the utilization rate of the incident light. At the same time, the doping layer 120 can also form a PN junction with the substrate 100 and realize selective carrier transport.

[0039] The first region 12, the second region 13, and the metal pattern region 10 of the non-metal pattern region 11 are successively adjacent to each other, and the height of the substrate 100 in the second region 13 is set between the height of the substrate 100 in the first region 12 and the height of the substrate 100 in the metal pattern region 10, thereby forming a stepped structure on the surface of the substrate 100 in the first region 12, the second region 13, and the metal pattern region 10. Because the doping layer 120 is disposed on the substrate 100 in the first region 12 and the second region 13, and the substrate 100 is exposed on the upper surface of the doping layer 120, a portion of the upper surface of the doping layer 120 also has a stepped structure. This increases the surface area of ​​the doping layer 120 compared to a flat surface, thereby increasing the active area of ​​the doping layer 120 and improving the performance of the doping layer 120.

[0040] As is apparent, the second region 13 is actually a transitional region between the first region 12 and the metal pattern region 10, and the presence of the second region 13 increases the area of ​​the doping layer 120. In this way, there is no need to create a textured structure on the surface of the substrate 100 in the first region 12 of the non-metal pattern region 11 to increase the surface area of ​​the doping layer 120, and this makes the surface of the substrate 100 in the first region 12 flat. Forming a first passivation layer on the surface of the substrate 100 in the first region 12 improves the flatness of the formed first passivation layer, further improving the passivation performance of the first passivation layer on the surface of the substrate 100 and further improving the photoelectric conversion performance of the solar cell.

[0041] In addition, the second region 13 is provided adjacent to the metal pattern region 10, increasing the area of ​​the portion of the doping layer 120 that is close to the metal pattern region 10. When the doping layer 120 performs the function of carrier transport, the path along which carriers are transported to the first passivation contact structure 110 in the metal electrode region is shortened, thereby improving the carrier transport performance.

[0042] Forming a step structure on the surface of the substrate 100 corresponds to increasing the surface area of ​​the substrate 100 in the height direction, which increases the area of ​​the doping layer 120 without increasing the cross-sectional area of ​​the substrate 100. This is advantageous for maintaining a high assembly density of the photovoltaic module when assembling solar cells to form a photovoltaic module, and for maintaining high module power. The height direction here refers to the direction in which the first passivation contact structure 110 faces the substrate 100. The cross-sectional area refers to the cross-sectional area in a direction parallel to the surface of the substrate 100.

[0043] As is apparent, in the embodiment of the present application, the first region 12 and the second region 13 are provided in the non-metallic pattern region 11, the first region 12, the second region 13, and the metallic pattern region 10 form a step structure, and the doping layer 120 is formed in the substrate 100 in the first region 12 and the second region 13, thereby reducing contact recombination loss of the metal electrodes, ensuring a high utilization rate of incident light in the solar cell, increasing the active area of ​​the doping layer 120, and improving the overall photoelectric conversion performance of the solar cell. The provision of the doping layer 120, the step structure on the surface of the substrate 100, and the first passivation contact structure 110 maximizes the advantages of the doping layer 120 and the first passivation contact structure 110, and significantly reduces the adverse effects of the doping layer 120 and the first passivation contact structure 110 on other structures of the solar cell, thereby cooperatively improving the overall performance of the solar cell.

[0044] It should be noted that the height of the substrate 100 surface of the first region 12 of the non-metallic pattern region 11, the height of the substrate 100 surface of the second region 13, and the height of the substrate 100 surface of the metal pattern region 10 all refer to other opposing surfaces of the substrate 100. For example, when the surface on which the first passivation contact structure 110 is located is the first surface of the substrate 100, the surface of the substrate 100 farther from the first passivation contact structure 110 is the second surface, and the first surface is disposed opposite to the second surface, and the height of the substrate 100 surface of the first region 12 of the non-metallic pattern region 11, the height of the substrate 100 surface of the second region 13, and the height of the substrate 100 surface of the metal pattern region 10 all refer to the second surface. In other words, the thickness of the substrate 100 in the first region 12 is smaller than the thickness of the substrate 100 in the metal pattern region 10, and the thickness of the substrate 100 in the second region 13 is neither smaller than the thickness of the substrate 100 in the first region 12 nor greater than the thickness of the substrate 100 in the metal pattern region 10.

[0045] The substrate 100 is used to receive incident light and generate photo-generated carriers. In some embodiments, the substrate 100 may be a silicon substrate, and the material of the silicon substrate may include at least one of monocrystalline silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon. In other embodiments, the material of the substrate 100 may be silicon carbide, an organic material, or a multi-component compound. Examples of multi-component compounds include, but are not limited to, perovskite, gallium arsenide, cadmium telluride, copper indium selenide, and the like.

[0046] In some embodiments, the solar cell is a TOPCON (Tunnel Oxide Passivated Contact) cell, and the substrate 100 includes two opposing surfaces, each of which is used to receive incident light and reflect light. In some embodiments, the substrate 100 includes a doping element, and the type of the doping element is N-type or P-type. The N-type element may be a Group V element such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As), and the P-type element may be a Group III element such as boron (B), aluminum (Al), gallium (Ga), or indium (In). For example, if the substrate 100 is a P-type substrate, the type of the doping element therein is P-type. Alternatively, if the substrate 100 is an N-type substrate, the type of the doping element therein is N-type.

[0047] In some embodiments, the semiconductor device further includes a first electrode 130 electrically connected to the first doped conductive layer 112 .

[0048] Photogenerated carriers generated in the substrate 100 are transported from the substrate 100 to the doped conductive layer and then to the first electrode 130 for collecting the photogenerated carriers. The first electrode 130 is provided on the metal pattern region 10.

[0049] In some embodiments, the doping element of first doped conductive layer 112 and the doping element of doped layer 120 are of the same group. In some embodiments, the doping element of first doped conductive layer 112 and the doping element of doped layer 120 may both be a Group 3 element, such as boron, gallium, or indium. In some embodiments, the elements of first doped conductive layer 112 and the doping element of doped layer 120 may both be a Group 5 element, such as phosphorus, arsenic, or antimony.

[0050] That is, the type of doping element in the first doped conductive layer 112 is the same as the type of doping element in the doped layer 120, and either may be a p-type doping element or an n-type doping element. The doping elements in the first doped conductive layer 112 and the doped layer 120 are set to be elements of the same family, that is, the doping elements in the first doped conductive layer 112 and the doped layer 120 are set to have the same number of electrons in their outermost layers, thereby making the chemical properties of the first doped conductive layer 112 and the doped layer 120 similar. In this way, the transport performance of carriers in the doped layer 120 to the first doped conductive layer 112 can be improved.

[0051] In some embodiments, the doping element concentration of the first doped conductive layer 112 is equal to or greater than the doping element concentration of the doped layer 120. In some embodiments, the doping element concentration of the first doped conductive layer 112 is greater than the doping element concentration of the doped layer 120 and greater than the doping element concentration of the substrate 100. This causes the first doped conductive layer 112 to form a doped region with a higher concentration than the substrate 100, which creates a barrier effect for carriers in the substrate 100, strengthens the ability of carriers in the substrate 100 to be transported to the first doped conductive layer 112, and enhances the tunneling ability of carriers in the first tunnel layer 111, which is advantageous for increasing the carrier concentration and for carrier collection at the first electrode 130.

[0052] By setting the doping element concentration of the doping layer 120 to be low, the doping layer 120 has a good surface passivation effect on the substrate 100. Furthermore, the doping element concentration difference between the doping layer 120 and the first doped conductive layer 112 can enhance the lateral transport of carriers between the doping layer 120 and the first doped conductive layer 112, and further improve the carrier collection ability.

[0053] In some embodiments, the doping element concentration of the first doped conductive layer 112 is 1×10 19 atoms / cm 3~9×10 20 atoms / cm 3 and the doping element concentration of the doped layer 120 is 1×10 16 atoms / cm 3 ~1×10 20 atoms / cm 3 For example, in some embodiments, the doping element concentration of the first doped conductive layer 112 is 1×10 19 atoms / cm 3 ~5×10 19 atoms / cm 3 , 5×10 19 atoms / cm 3 ~9×10 19 atoms / cm 3 , 9×10 19 atoms / cm 3 ~1×10 20 atoms / cm 3 , 1×10 20 atoms / cm 3 ~2×10 20 atoms / cm 3 , 2 × 10 20 atoms / cm 3 ~4×10 20 atoms / cm 3 , 4×10 20 atoms / cm 3 ~5×10 20 atoms / cm 3 , 5×10 20 atoms / cm 3 ~6×10 20 atoms / cm 3 , 6×10 20 atoms / cm 3 ~8×10 20 atoms / cm 3 or 8×10 20 atoms / cm 3 ~9×10 20 atoms / cm 3 In some embodiments, the doping element concentration of the doped layer 120 may be 1×10 16 atoms / cm 3 ~5×10 16 atoms / cm3 , 5×10 16 atoms / cm 3 ~9×10 16 atoms / cm 3 , 9×10 16 atoms / cm 3 ~1×10 17 atoms / cm 3 , 1×10 17 atoms / cm 3 ~1×10 18 atoms / cm 3 , 1×10 18 atoms / cm 3 ~5×10 18 atoms / cm 3 , 5×10 18 atoms / cm 3 ~9×10 18 atoms / cm 3 , 9×10 18 atoms / cm 3 ~1×10 19 atoms / cm 3 , 1×10 19 atoms / cm 3 ~5×10 19 atoms / cm 3 , 5×10 19 atoms / cm 3 ~9×10 19 atoms / cm 3 or 9×10 19 atoms / cm 3 ~1×10 20 atoms / cm 3 Increasing the doping element concentration of the first doped conductive layer 112 within the above range helps to strengthen carrier transport in the first doped conductive layer 112 and enhance carrier tunneling in the first tunneling layer 111. In addition, decreasing the doping element concentration of the doped layer 120 within the above range allows the doped layer 120 to have a good surface passivation effect on the surface of the substrate 100 in the non-metal pattern region 11 and reduce carrier recombination on the surface of the substrate 100 in the non-metal pattern region 11.

[0054] Furthermore, within the above range, the doping element concentration of the first doped conductive layer 112 may be higher than the doping element concentration of the doped layer 120. This allows the first doped conductive layer 112 to form a doped region with a higher concentration than the doped layer 120, which further creates a barrier effect for carriers in the doped layer 120, strengthening the ability of the doped layer 120 to transport carriers to the first doped conductive layer 112 and helping to improve the carrier collection ability.

[0055] In some embodiments, the doping element concentration of the doped layer 120 may be equal to the doping element concentration of the first doped conductive layer 112 .

[0056] In some embodiments, the type of doping element in the doped layer is different from the type of doping element in the substrate 100. That is, the doped layer 120 can act as an emitter and form a PN junction with the substrate 100. The PN junction is used to receive incident light and generate photo-generated carriers, which can be transported from the substrate 100 to the first doped conductive layer 112 and then to the first electrode 130, which is used to collect the photo-generated carriers. The photo-generated carriers can be transported through the doped layer 120, transported from the doped layer 120 to the first doped conductive layer, and then collected by the first electrode 130.

[0057] In some embodiments, the type of doping element in the first doped conductive layer 112 is different from the type of doping element in the substrate 100, i.e., the type of doping element in the first doped conductive layer 112 is also different from the type of doping element in the substrate 100, so that a PN junction can be formed between the first doped conductive layer 112 and the substrate 100, which can increase the number of photogenerated carriers generated, increase the carrier concentration, improve the backing factor, and increase the short-circuit current and open-circuit voltage.

[0058] Compared to providing a first doped conductive layer 112 on both the surface of the substrate 100 in the non-metal pattern region 11 and the surface of the substrate 100 in the metal pattern region 10 to form a PN junction with the substrate 100, or providing a doped layer 120 as an emitter on both the surface of the substrate 100 in the non-metal pattern region 11 and the surface of the substrate 100 in the metal pattern region 10, providing a first doped conductive layer 112 only on the surface of the substrate 100 in the metal pattern region 10 to form a PN junction with the substrate 100, and having the first electrode 130 in electrical contact with the first doped conductive layer 112, it is possible to reduce metal contact recombination of the first electrode 130 and improve the carrier collection ability of the first electrode 130. On the other hand, by providing a doping layer 120 on the substrate 100 of the non-metallic pattern region 11, the doping layer 120 forming a PN junction with the substrate 100, and making the doping layer 120 and the substrate 100 of the same material, the parasitic absorption of incident light by the substrate 100 of the non-metallic pattern region 11 can be significantly reduced compared to using the first doping conductive layer 112, and the utilization rate of incident light can be increased.

[0059] In some embodiments, the type of doping element in the doped layer 120 and the type of doping element in the first doped conductive layer 112 may both be p-type, such as phosphorus, bismuth, antimony, or arsenic, and the type of doping element in the substrate 100 may be n-type, such as boron or gallium.

[0060] In some embodiments, the doping element concentration of the doped layer 120 is greater than the doping element concentration of the substrate 100. In other words, the doping element concentration of the doped layer 120 is greater than the doping element concentration of the region of the substrate 100 other than the doped layer 120. As a result, the doped layer 120 is highly doped compared to the region of the substrate 100 other than the doped layer 120, and a concentration gradient of the same doping element type is formed between the doped layer 120 and the region of the substrate 100 other than the doped layer 120, thereby forming a back surface field that can effectively collect photogenerated carriers.

[0061] As can be seen, because the doping layer 120 is located on the substrate 100 in the first region 12 and the second region 13, the upper surface of the doping layer 120 has a stepped structure, which further increases the surface area of ​​the doping layer 120. If the doping layer 120 is used as the emitter of a solar cell, the area of ​​the formed PN junction can be increased, which increases the number of photogenerated carriers generated by the PN junction, increases the carrier concentration, and increases the open circuit voltage and short circuit current.

[0062] In some embodiments, if the doped layer 120 is a PN junction, the doped layer 120 needs to be in contact with the incident light as much as possible so that a large amount of incident light is irradiated onto the upper surface of the doped layer 120. Based on this, the surface of the substrate 100 in the second region 13 may be inclined relative to the surface of the substrate 100 in the first region 12, and the angle formed between the surface of the substrate 100 in the second region 13 and the surface of the substrate 100 in the first region 12 may be set to be an obtuse angle. This allows the surface of the substrate 100 in the second region 13 to be exposed to the outside as much as possible, reducing shading of the surface of the substrate 100 in the second region 13 and further increasing the utilization rate of the substrate 100 for incident light.

[0063] Furthermore, by setting the surface of the substrate 100 in the second region 13 so that it is inclined compared to the surface of the substrate 100 in the first region 12, when the height difference between the surface of the substrate 100 in the first region 12 and the surface of the substrate 100 in the metal pattern region 10 is constant, the surface area of ​​the surface of the substrate 100 in the second region 13 can be increased, and the surface area of ​​the doping layer 120 can also be increased, compared to when the surface of the substrate 100 in the second region 13 is perpendicular to the surface of the substrate 100 in the first region 12.

[0064] In some embodiments, there is a first included angle θ between the surface of the substrate 100 in the first region 12 and the surface of the substrate 100 in the second region 13, and the first included angle θ may be between 90° and 160°, for example, between 90° and 95°, between 95° and 100°, between 100° and 105°, between 105° and 110°, between 110° and 115°, between 115° and 120°, between 120° and 125°, between 125° and 130°, between 130° and 135°, between 135° and 140°, between 140° and 145°, between 145° and 150°, between 150° and 155°, or between 155° and 160°. Within this range, if the surface of the substrate 100 in the second region 13 is tilted relative to the surface of the substrate 100 in the first region 12, the surface area of ​​the substrate 100 in the second region 13 can be increased, further increasing the surface area of ​​the doped layer 120. If the doped layer 120 is used as the emitter of the solar cell, the area of ​​the formed PN junction can be increased, generating more photogenerated carriers and improving the photoelectric performance of the solar cell.

[0065] As shown in FIG. 3, in some embodiments, the surface of the substrate 100 in the first region 12 may be perpendicular to the surface of the substrate 100 in the second region 13 .

[0066] As shown in FIGS. 1 and 3 , in some embodiments, the height difference d between the surface of the substrate 100 in the metal pattern region and the surface of the substrate 100 in the first region 12 is 0.1 μm to 10 μm, for example, 0.1 μm to 0.2 μm, 0.2 μm to 0.5 μm, 0.5 μm to 1 μm, 1 μm to 1.5 μm, 1.5 μm to 2 μm, 2 μm to 2.5 μm, 2.5 μm to 3 μm, 3 μm to 3.1 μm, 3.1 μm to The height difference d may be 3.2 μm, 3.2 μm to 3.5 μm, 3.5 μm to 3.8 μm, 3.8 μm to 3.9 μm, 3.9 μm to 4 μm, 4 μm to 4.5 μm, 4.5 μm to 5 μm, 5 μm to 5.5 μm, 5.5 μm to 6 μm, 6 μm to 6.5 μm, 6.5 μm to 7 μm, 7 μm to 7.5 μm, 7.5 μm to 8 μm, 8 μm to 8.5 μm, 8.5 μm to 9 μm, or 9 μm to 10 μm. Within this range of height difference d, increasing the height difference between the surface of substrate 100 in first region 12 and the surface of substrate 100 in metal pattern region 10 allows the surface area of ​​substrate 100 located in second region 13 to be large, increasing the area of ​​doped layer 120, and improving the ability to generate photogenerated carriers when doped layer 120 is used as an emitter. On the other hand, within this range, the difference in height between the surface of the substrate 100 in the first region 12 and the surface of the substrate 100 in the metal pattern region 10 is not too large, which can avoid the problem of high defect level density on the surface of the substrate 100 caused by excessive etching of the substrate 100 during the process of actually forming the substrate 100 in the first region 12, the second region 13 and the metal pattern region 10, and further reduces carrier recombination on the surface of the substrate 100, helping to improve the backing factor of the solar cell.

[0067] In some embodiments, the doping element concentration of the doped layer 120 in the second region 13 is not less than the doping element concentration of the doped layer 120 in the first region 12 and not greater than the doping element concentration of the first doped conductive layer 112 .

[0068] In some embodiments, the doping element concentration in the second region 13 may be greater than the doping element concentration in the doping layer 120 in the first region 12 and less than the doping element concentration in the first doped conductive layer 112. That is, the doping element concentration in the doping layer 120 in the second region 13 is between the doping element concentration in the first region 12 and the doping element concentration in the first doped conductive layer 112. When carriers are transported between the doping layer 120 and the first doped conductive layer 112, the presence of the doping layer 120 in the second region 13 prevents carriers from transporting through the first doped conductive layer 112 and the doping layer 120, which have a large difference in doping element concentration, resulting in a large potential energy difference between the doping layer 120 in the first region 12 and the first doped conductive layer 112 in the metal pattern region 10, which reduces the efficiency of lateral carrier transport. That is, the doping layer 120 in the second region 13 performs a transitional function, reducing the potential energy difference for carriers transporting through the doping layer 120 in the first region 12 and the first doped conductive layer 112, ensuring the effectiveness of lateral carrier transport, and improving the backing factor of the solar cell.

[0069] In some embodiments, the doping element concentration of the doped layer 120 in the second region 13 gradually decreases from the side of the doped layer 120 in the first region 12 facing the first doped conductive layer 112 to the side of the doped layer 120 in the first region 12 facing away from the first doped conductive layer 112. By setting the doping element concentration of the doped layer 120 in the second region 13 to gradually change, the potential energy difference for carrier transport between the doped layer 120 in the first region 12 and the first doped conductive layer 112 can be further reduced, and the lateral transport ability of carriers can be further improved.

[0070] Furthermore, by setting the height of the surface of the substrate 100 in the second region 13 to be not lower than the height of the surface of the substrate 100 in the first region 12, part of a step structure is formed between the surface of the substrate 100 in the second region 13 and the surface of the substrate 100 in the first region 12, and for example, the surface of the substrate 100 in the second region 13 is perpendicular or inclined to the surface of the substrate 100 in the first region 12, that is, the surface of the substrate 100 in the second region 13 has a height difference in the direction perpendicular to the surface of the substrate 100 in the first region 12. This is advantageous in that in the process of actually doping the surface of the substrate 100 in the first region 12 and the second region 13, the doping rate of the doping element in the substrate 100 in the second region 13 does not match in the direction perpendicular to the surface of the substrate 100 in the first region 12, and furthermore, in that the doping element concentration in the doped layer 120 in the second region 13 gradually changes, for example, in the direction from the first doped conductive layer 112 to the doped layer 120 in the first region 12, the doping element concentration in the doped layer 120 in the second region 13 gradually decreases.

[0071] In some embodiments, the difference between the doping concentration of the surface of the doped layer 120 in the second region 13 facing the first doped conductive layer 112 and the doping concentration of the surface of the doped layer 120 in the second region 13 facing away from the first doped conductive layer 112 is greater than or equal to 1×10 19 atoms / cm 3 ~8×10 20 atoms / cm 3 For example, 1×10 19 atoms / cm 3 ~3×10 19 atoms / cm 3 , 3×10 19 atoms / cm 3 ~5×10 19 atoms / cm 3 , 5×10 19 atoms / cm 3 ~7×10 19 atoms / cm 3 , 7×10 19 atoms / cm 3 ~9×10 19 atoms / cm 3 , 9×10 19atoms / cm 3 ~1×10 20 atoms / cm 3 , 1×10 20 atoms / cm 3 ~3×10 20 atoms / cm 3 , 3×10 20 atoms / cm 3 ~5×10 20 atoms / cm 3 or 5×10 20 atoms / cm 3 ~8×10 20 atoms / cm 3 Within this range, it is possible to ensure that the potential energy difference occurring during the carrier transport process between the doped layer 120 of the first region 12 and the first doped conductive layer 112 is small, thereby ensuring the effectiveness of the lateral transport of carriers.

[0072] In some embodiments, the doping element concentration on the side of the doped layer 120 in the second region 13 facing the first doped conductive layer 112 may be equal to the doping element concentration in the first doped conductive layer 112, and the doping element concentration on the side of the doped layer 120 in the second region 13 away from the first doped conductive layer 112 may be equal to the doping element concentration in the first region 12. This can reduce the potential energy difference of carriers at the contact interface between the doped layer 120 in the second region 13 and the first doped conductive layer 112, and can also reduce the potential energy difference of carriers at the contact interface between the doped layer 120 in the second region 13 and the doped layer 120 in the first region 12, which helps to further improve the lateral transport ability of carriers.

[0073] In some embodiments, the doping element concentration in the second region 13 may be equal to the doping element concentration in the first region 12 and the doping element concentration in the first doped conductive layer 112 .

[0074] The sheet resistance of the doped layer 120 can be adjusted by controlling the doping element concentration of the doped layer 120 in the first region 12 and the second region 13. For example, when the doping element concentration of the doped layer 120 is low overall, adjusting the sheet resistance of the doped layer 120 to be larger can reduce the carrier recombination centers on the surface of the doped layer 120, reduce carrier recombination on the surface of the doped layer 120, increase the carrier concentration, and further increase the open circuit voltage and backing factor of the solar cell, thereby improving the conversion efficiency of the solar cell.

[0075] In some embodiments, the sheet resistance of the doping layer 120 may be between 80 ohm / sq and 1000 ohm / sq, for example, between 80 ohm / sq and 100 ohm / sq, between 100 ohm / sq and 130 ohm / sq, between 130 ohm / sq and 150 ohm / sq, between 150 ohm / sq and 280 ohm / sq, between 280 ohm / sq and 450 ohm / sq, between 450 ohm / sq and 600 ohm / sq, between 600 ohm / sq and 720 ohm / sq, between 720 ohm / sq and 850 ohm / sq, between 850 ohm / sq and 900 ohm / sq, between 900 ohm / sq and 950 ohm / sq, or between 950 ohm / sq and 1000 ohm / sq. Within this range, fewer carrier recombination centers are generated on the surface of the doping layer 120, which improves the carrier concentration, enhances the carrier transport performance, increases the open circuit voltage and backing factor of the solar cell, and improves the conversion efficiency of the solar cell.

[0076] In some embodiments, the surface of the substrate 100 in the metal pattern region 10 has a first texture structure, and the surface of the substrate 100 in the non-metal pattern region 11 has a second texture structure, with the roughness of the first texture structure being greater than the roughness of the second texture structure. Setting the roughness of the first texture structure to be greater increases the surface area of ​​the surface of the substrate 100 in the metal pattern region 10, and allows the first passivation contact structure 110 located on the surface of the substrate 100 in the metal pattern region 10 to continue the morphology of the surface of the substrate 100 in the metal pattern region 10. That is, the upper surface of the first passivation contact structure 110 also has a large roughness, which increases the surface area of ​​the first passivation contact structure 110 and provides a large contact area between the first electrode 130 located on the first passivation contact structure 110 and the first passivation contact structure 110, thereby reducing the contact resistance of the first electrode 130 and improving carrier transport performance.

[0077] Because the surface of the substrate 100 has a stepped structure and the surface area of ​​the substrate 100 increases in the height direction, the roughness of the second texture structure can be reduced to flatten the surface of the substrate 100 in the non-metallic pattern region 11. Therefore, when the first passivation layer is formed on the upper surface of the doping layer 120 in the non-metallic pattern region 11, the first passivation layer can be uniformly covered on the surface of the doping layer 120 during the formation of the first passivation layer. This flattens the morphology of the first passivation layer, optimizes the interface morphology between the first passivation layer and the surface of the doping layer 120, and reduces the interface state density. This not only helps reduce carrier recombination on the surface of the doping layer 120 in the non-metallic pattern region 11, but also strengthens the tunneling ability of carriers, increases the number of carriers, and improves the photoelectric conversion performance of the solar cell.

[0078] In some embodiments, the first texture structure may be a pyramid structure, and the second texture structure may be a platform protrusion structure. In some embodiments, the pyramid structure may be a tetrahedron, an approximate tetrahedron, a pentahedron, or an approximate pentahedron. The platform protrusion structure is the base of the pyramid structure, i.e., the bottom structure after removing the tip portion from the pyramid structure. In some embodiments, the second texture structure may be a similar platform protrusion structure, and the top surface of the similar platform protrusion structure may be a flat or inclined surface, and the bottom surface of the similar platform protrusion structure may be a polygonal plane, such as a quadrilateral plane or a pentagonal plane.

[0079] 2 , in some embodiments, the first passivation contact structure 110 includes a plurality of sub-first passivation contact structures 113 stacked along a direction away from the substrate 100, and the sub-first passivation contact structures 113 include first tunnel layers 111 and first doped conductive layers 112 stacked along a direction away from the substrate 100. That is, each first tunnel layer 111 in the plurality of first tunnel layers 111 is stacked alternately with each first doped conductive layer 112 in the plurality of first doped conductive layers 112.

[0080] In some embodiments, the first passivation contact structure 110 may include only one first tunneling layer 111 and one first doped conductive layer 112, and the first tunneling layer 111 is located on the surface of the substrate 100. The first tunneling layer 111 provides a tunneling path for carriers and enhances the selective transport ability of carriers.

[0081] In some embodiments, the material of the first doped conductive layer 112 may include at least one of amorphous silicon, polycrystalline silicon, and silicon carbide. In some embodiments, the material of the first tunneling layer 111 may include at least one of silicon oxide, aluminum oxide, silicon nitride, silicon oxynitride, amorphous silicon, or polycrystalline silicon.

[0082] As shown in FIG. 1, in some embodiments, the substrate 100 further includes a second passivation contact structure 150 located on a surface thereof away from the first passivation contact structure 110, the second passivation contact structure 150 including at least one second tunnel layer 151 and at least one second doped conductive layer 152 stacked along a direction away from the substrate 100.

[0083] The second doped conductive layer 152 has the effect of field-effect passivation, which allows minority carriers to escape from the interface, reduces the minority carrier concentration, and reduces the carrier recombination rate at the interface with the substrate 100, thereby increasing the open circuit voltage, short circuit current, and backing factor of the solar cell and improving the photoelectric conversion performance of the solar cell.

[0084] In some embodiments, the type of doping element in the first doped conductive layer 112 is different from the type of doping element in the substrate 100, and the type of doping element in the second doped conductive layer 152 is the same as the type of doping element in the substrate 100. The doping element concentration in the second doped conductive layer 152 is greater than the doping element concentration in the substrate 100, so that the second doped conductive layer 152 forms a high-low junction with the substrate 100, which is beneficial to forming a carrier barrier effect and can enhance carrier transport.

[0085] The second tunnel layer 151 is used to achieve interface passivation of the surface of the substrate 100, and exerts the effect of chemical passivation, specifically, by saturating the dangling bonds on the surface of the substrate, reducing the density of interface defect states on the surface of the substrate 100 and reducing the recombination centers on the surface of the substrate 100.

[0086] In some embodiments, the second passivation contact structure 150 may include only one second tunnel layer 151 and one second doped conductive layer 152 stacked along a direction away from the substrate 100.

[0087] In some embodiments, the second passivation contact structure 150 may include a plurality of sub-second passivation contact structures stacked along a direction away from the substrate 100, and each sub-second passivation contact structure includes a second tunnel layer 151 and a second doped conductive layer 152 stacked along a direction away from the substrate 100. That is, each second tunnel layer 151 in the plurality of second tunnel layers 151 is stacked alternately with each second doped conductive layer 152 in the plurality of second doped conductive layers 152.

[0088] Some embodiments further include a first passivation layer 140 located on top of the doping layer 120 and on top and side surfaces of the first passivation contact structure 110 .

[0089] The first passivation layer 140 is located on the upper surface of the doping layer 120 in the first region 12 and the upper surface of the doping layer 120 in the second region 13, and has a good passivation effect on the substrate surface of the non-metallic pattern region 11, can effectively chemically passivate the dangling bonds on the substrate surface of the non-metallic pattern region 11, reduce the defect level density on the substrate surface of the non-metallic pattern region 11, suppress carrier recombination on the substrate surface of the non-metallic pattern region 11, and increase the carrier concentration.

[0090] The first passivation layer 140 is located on the top and side surfaces of the first passivation contact structure 110, i.e., the first passivation layer 140 covers the top and side surfaces of the first passivation contact structure 110, and provides good passivation effects to the surface of the substrate 100 in the metal pattern region 10, the top and side surfaces of the first doped conductive layer 112, and the side surfaces of the first tunnel layer 111, thereby suppressing carrier recombination on the surface of the substrate 100 in the metal pattern region 10, the surface of the first doped conductive layer 112, and the side surfaces of the first tunnel layer 111, thereby increasing the carrier concentration in the surface of the substrate 100 in the metal pattern region 10, the first doped conductive layer 112, and the first tunnel layer 111, and strengthening the carrier collection ability of the first electrode 130.

[0091] In some embodiments, the height of the first passivation layer 140 located on the upper surface of the doping layer 120 in the first region 12 is lower than the height of the first passivation layer 140 in the metal pattern region 10, and the height of the first passivation layer 140 located on the upper surface of the doping layer 120 in the second region 13 is between the height of the first passivation layer 140 located on the upper surface of the doping layer 120 in the first region 12 and the height of the first passivation layer 140 in the metal pattern region 10. That is, the upper surface of the first passivation layer 140 also forms a stepped structure.

[0092] As can be understood, the height of the first passivation layer 140 located on the upper surface of the doping layer 120 in the first region 12, the height of the first passivation layer 140 located on the upper surface of the doping layer 120 in the second region 13, and the height of the first passivation layer 140 located on the metal pattern region 10 are all referenced to the surface of the substrate 100 away from the first passivation layer 140.

[0093] In some embodiments, the first passivation layer 140 may be a single layer structure, and in other embodiments, the first passivation layer 140 may be a multi-layer structure. In some embodiments, the material of the first passivation layer 140 may be at least one of silicon oxide, aluminum oxide, silicon nitride, or silicon oxynitride.

[0094] In some embodiments, the semiconductor device further includes a first electrode 130 that penetrates the first passivation layer 170 and is electrically connected to the first doped conductive layer 112 .

[0095] In some embodiments, the first electrode 130 may penetrate the first passivation layer 140 and the first doped conductive layer 112 to make electrical contact with the first tunneling layer 111 .

[0096] In some embodiments, the second passivation contact structure 150 further includes a second passivation layer 160 located on the surface of the second passivation contact structure 150 facing away from the substrate 100. The second passivation layer 160 provides a good passivation effect for the second surface of the substrate 100, reduces the defect state density on the second surface, and effectively suppresses carrier recombination on the back surface of the substrate 100. The second passivation layer 160 also provides a good reflection reduction effect, which helps reduce the reflection of incident light and improve the utilization efficiency of the incident light.

[0097] In some embodiments, the second passivation layer 160 may have a single layer structure, while in other embodiments, the second passivation layer 160 may have a multi-layer structure. In some embodiments, the material of the second passivation layer 160 may be at least one of silicon oxide, aluminum oxide, silicon nitride, or silicon oxynitride.

[0098] In some embodiments, the semiconductor device further includes a second electrode 170 located on the second surface of the substrate 100 and extending through the second passivation layer 160 in electrical contact with the second doped conductive layer 152 .

[0099] In the solar cell provided according to the above embodiment, a doping layer 120 made of the same material as the substrate 100 is provided on the substrate 100, thereby significantly reducing parasitic absorption of incident light in the doping layer 120. A passivation contact structure is formed on the substrate 100 in the metal pattern region 10, and the passivation contact structure serves to reduce contact recombination loss of the metal electrode. The first region 12 and the second region 13 of the non-metal pattern region 11 are sequentially in contact with the metal pattern region 10, forming a step structure on the surface of the substrate 100. As a result, the upper surface of the doping layer 120 formed on the top portion of the substrate 100 also has a step structure shape, which increases the area of ​​the formed doping layer 120 and the active area of ​​the doping layer 120, reducing contact recombination loss of the metal electrode while ensuring high utilization of incident light in the solar cell. The active area of ​​the doping layer 120 also increases, thereby improving the overall photoelectric conversion performance of the solar cell. Comparative Example

[0100] In the comparative example, a solar cell was provided, and the differences between the structure of the solar cell in the comparative example and the structure of the solar cell provided in the examples of the present application are as follows. As shown in FIG. 1 , in the solar cell provided by the embodiment of the present application, the surface of the substrate 100 in the non-metallic pattern region 11 comprises a first region 12 and a second region 13, the surface of the substrate 100 in the first region 12 being lower than the surface of the substrate 100 in the metallic pattern region 10, and the height of the surface of the substrate 100 in the second region 13 being not lower than the surface of the substrate 100 in the first region 12 nor higher than the surface of the substrate 100 in the metallic pattern region 10. A doping layer 120 is disposed on the substrate 100 in the first region 12 and the second region 13, and the upper surface of the doping layer 120 is exposed on the substrate 100. A first passivation contact structure 110 is disposed on the surface of the substrate 100 in the metallic pattern region 10. In the comparative example, the substrate surface is flat, and a doping layer is disposed on the substrate in the metallic pattern region and the substrate in the non-metallic pattern region, with the substrate being exposed on the upper surface of the doping layer. Table 1 shows a comparison of the parameters between the embodiment of the present application and the comparative example based on a comparative experiment.

[0101] Table 1 JPEG0007796804000001.jpg41161

[0102] As can be seen from Table 1, the open-circuit voltage, fill factor, and conversion efficiency of the solar cell in the example of the present application are higher than those in the comparative example. This is because in the example of the present application, the first doped conductive layer 112 is disposed only on the surface of the substrate 100 in the metal pattern region 10, and the first electrode 130 is in electrical contact with the first doped conductive layer 112, reducing metal contact recombination in the first electrode 130 and improving the carrier collection ability of the first electrode 130. On the other hand, compared to when the doped layer 120 is disposed on the substrate 100 in the non-metal pattern region 11, and the doped layer 120 and the substrate 100 are made of the same material and the first doped conductive layer 112 is used, parasitic absorption of incident light in the substrate 100 in the non-metal pattern region 11 is significantly reduced, thereby improving the utilization rate of incident light. In addition, the surface of the substrate 100 in the first region 12, the second region 13 and the metal pattern region 10 forms a step structure, and compared to the surface of the substrate 100 in the non-metal pattern region 11 in the comparative example, the area of ​​the surface of the substrate 100 in the non-metal pattern region 11 is increased in the embodiment of the present application, and the area of ​​the doping layer 120 in the non-metal pattern region 11 is also increased, thereby reducing metal contact recombination in the metal pattern region 10 while ensuring that the doping layer 120 has a large active area, thereby improving the photoelectric conversion performance of the solar cell.

[0103] Correspondingly, another aspect of the embodiment of the present application further provides a photovoltaic module, and referring to Fig. 4, the photovoltaic module includes a cell string formed by connecting a plurality of solar cells 101 provided in the above-described embodiment, an encapsulation layer 102 used to cover the surface of the cell string, and a cover plate 103 used to cover the surface of the encapsulation layer 102 remote from the cell string. The solar cells 101 are electrically connected as a whole or in the form of a plurality of slices to form a plurality of cell strings, and the plurality of cell strings are electrically connected in series and / or parallel.

[0104] Specifically, in some embodiments, multiple cell strings can be electrically connected by conduction bands 104. The encapsulation layer 102 covers the front and back surfaces of the solar cells 101. Specifically, the encapsulation layer 102 can be an organic encapsulation film such as an ethylene-vinyl acetate copolymer (EVA) adhesive film, a polyethylene octene elastomer (POE) adhesive film, a polyethylene terephthalate (PET) adhesive film, or polyvinyl butyral (PVB). In some embodiments, the cover plate 103 can be a light-transmitting cover plate 103 such as a glass cover plate or a plastic cover plate. Specifically, the surface of the cover plate 103 facing the encapsulation layer 102 can be textured, thereby increasing the utilization efficiency of incident light.

[0105] Correspondingly, an embodiment of the present application further provides a method for manufacturing a solar cell, including the following steps:

[0106] 5, a substrate 100 is provided, the substrate 100 having an initial surface 40, the initial surface 40 of the substrate 100 having a metal pattern region and a non-metal pattern region. The metal pattern region is defined as an electrode region, and the non-metal pattern region is a region on the surface of the substrate 100 other than the metal pattern region.

[0107] The substrate 100 is used to receive incident light and generate photo-generated carriers, and both the front and back surfaces of the substrate 100 can be used to receive incident light or reflect light. In some embodiments, the substrate 100 can be a silicon substrate, and the material of the silicon substrate can include at least one of monocrystalline silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon.

[0108] In some embodiments, the substrate 100 may be an N-type semiconductor substrate, and the doping element of the substrate 100 may be any of phosphorus, arsenic, or antimony.

[0109] In some embodiments, the substrate 100 may be a P-type semiconductor substrate, and the doping element of the substrate 100 may be either boron, gallium, or indium.

[0110] In some embodiments, the solar cell formed is a TOPCON cell.

[0111] 6 to 8, an initial first passivation contact structure 14 and a dielectric layer 20 are sequentially stacked on an initial surface 40 (see FIG. 5) of the substrate 100 in a direction away from the substrate 100. The initial first passivation contact structure 14 serves as a base for subsequently forming the first passivation contact structure, and the dielectric layer 20 is used as a mask for patterning the initial first passivation contact and is subsequently used to form the first passivation contact structure.

[0112] As shown in Figures 6 and 7, in some embodiments, a method for forming an initial first passivation contact structure 14 includes forming at least one initial first tunnel layer 15 and at least one initial first doped conductive layer 16 on an initial surface 40 of the substrate 100, stacked sequentially along a direction away from the substrate 100.

[0113] In some embodiments, the initial first passivation contact structure 14 may include only one initial first doped conductive layer 16 and one initial first tunnel layer 15, and the formed first passivation contact structure includes only one first doped conductive layer and one first tunnel layer.

[0114] In some embodiments, the initial first passivation contact structure 14 may include multiple layers of the initial first doped conductive layer 16 and multiple layers of the initial first tunnel layer 15, where one initial first doped conductive layer 16 and one initial first tunnel layer 15 are alternately stacked along the direction away from the substrate 100. The formed first passivation contact structure includes multiple layers of the first doped conductive layer and multiple layers of the first tunnel layer, where the first doped conductive layer and the first tunnel layer are alternately stacked along the direction away from the substrate 100.

[0115] As shown in FIG. 6, in some embodiments, a deposition process may be employed to form the initial first tunnel layer 15 on the initial surface of the substrate 100, and the deposition process may include either atomic layer deposition or chemical vapor deposition.

[0116] In some embodiments, the material of the initial first tunneling layer 15 may include at least one of silicon oxide, aluminum oxide, silicon nitride, silicon oxynitride, amorphous silicon, or polycrystalline silicon.

[0117] As shown in FIG. 7, in some embodiments, a method for forming the initial first doped conductive layer 16 includes the following steps.

[0118] The method includes using a deposition process to form a first dopable layer on the surface of the initial first tunnel layer 15, and then using an in-situ deposition process to inject a doping element into the first dopable layer during the deposition process to form an initial first doped conductive layer. By simultaneously performing the deposition process and the doping element injection process, process time can be saved and process efficiency can be improved.

[0119] After the doping element is implanted into the first dopable layer, an annealing process is performed on the first doped conductive layer to form the first doped conductive layer 16. The annealing process can activate the doping element in the first doped conductive layer to form an activated doping element. In some embodiments, the type of doping element implanted into the first dopable layer is different from the type of doping element in the substrate 100 so that the formed first doped conductive layer forms a PN junction with the substrate 100. In some embodiments, the type of doping element in the substrate 100 can be N-type, such as boron, gallium, or indium. The first doping element can be P-type, such as phosphorus, bismuth, antimony, or arsenic.

[0120] In some embodiments, the material of the first dopable layer may be any of amorphous silicon, polycrystalline silicon, microcrystalline silicon, or silicon carbide.

[0121] 8, in some embodiments, a method for forming a dielectric layer 20 includes forming the dielectric layer 20 on top of the initial first doped conductive layer 16 using a deposition process, where the material of the dielectric layer 20 includes one of silicon oxide, silicon nitride, aluminum oxide, or silicon oxynitride. The deposition process may be one of an atomic layer deposition process or a chemical vapor deposition process.

[0122] In some embodiments, the initial first doped conductive layer 16 and the dielectric layer 20 may be formed in the same process steps. A method for forming the initial first doped conductive layer 16 and the dielectric layer 20 includes the following steps.

[0123] A deposition process is used to form the first dopable layer.

[0124] A doping source containing a first doping element is deposited on the top surface of the first dopable layer. Simultaneously with the deposition of the doping source, oxygen gas is introduced, and the oxygen gas and the first dopable layer react to form dielectric layer 20 having the first doping element. In some embodiments, the material of the first dopable layer is polycrystalline silicon, and the oxygen reacts with the polycrystalline silicon to produce silicon oxide. The oxygen further reacts with the first doping element. If the first doping element is boron, the oxygen and boron react to produce boron oxide, and the silicon oxide and boron oxide form borosilicate glass, which then forms dielectric layer 20. In some embodiments, if the first doping element is phosphorus, a phosphorus-containing silicon glass layer is formed, and the phosphorus-containing silicon glass layer becomes dielectric layer 20.

[0125] As shown in FIGS. 9 to 11, a patterning process is performed on the dielectric layer 20 so as to form a first opening 21 in the dielectric layer 20, and the first opening 21 directly faces the non-metal pattern region 11.

[0126] As shown in FIG. 9, in some embodiments, performing a patterning process on the dielectric layer 20 may include laser processing the dielectric layer 20 in the non-metallic pattern region 11 using a laser process to remove the dielectric layer 20 in the non-metallic pattern region 11, forming a first opening 21, and exposing the initial first passivation contact structure 14 in the non-metallic pattern region 11 through the first opening 21.

[0127] Compared to the process of patterning the dielectric layer 20 by a chemical etching process, etching and removing the dielectric layer 20 in the non-metallic pattern area 11 by laser processing greatly simplifies the process and improves process efficiency.

[0128] In some embodiments, the laser wavelength of the first laser step is 248 nm to 532 nm, such as 248 nm to 255 nm, 255 nm to 275 nm, 275 nm to 290 nm, 290 nm to 315 nm, 315 nm to 340 nm, 340 nm to 355 nm, 355 nm to 370 nm, 370 nm to 405 nm, 405 nm to 445 nm, 445 nm to 480 nm, 480 nm to 495 nm, 495 nm to 505 nm, 505 nm to 520 nm, or 520 nm to 532 nm. Within this range, the laser energy employed in the first laser step is sufficient to remove the dielectric layer 20 in the non-metallic pattern region 11. Furthermore, within this range, the laser energy used in the first laser process should not be too large, preventing the problem of over-etching the initial first passivation contact structure 14 covered by the dielectric layer 20 due to excessive laser energy, and ensuring that the initial first passivation contact structure 14 has a flat surface.

[0129] As shown in Figures 10-11, in some embodiments, performing a patterning process on the dielectric layer 20 may include forming an ink layer 30 on the upper surface of the dielectric layer 20 in the metal pattern region 10 directly facing the metal pattern region 10 (see Figure 9), and acid-washing the dielectric layer 20 to remove the dielectric layer 20 in the non-metal pattern region 11, forming a first opening 21, and exposing the initial first passivation contact structure 14 in the non-metal pattern region 11 through the first opening 21.

[0130] In the process of patterning the dielectric layer 20, the ink layer 30 is formed on the surface of the dielectric layer 20 that does not need to be removed, and since the ink layer 30 can be formed by a process such as coating, the pattern of the ink layer 30 can be precisely controlled, and further, the size of the dielectric layer 20 can be precisely controlled. Utilizing the acid-insoluble property of the ink layer 30, an acid washing process can be used to remove the dielectric layer 20 that is not covered by the ink layer 30, further exposing the surface of the initial first passivation contact structure 14 in the non-metal pattern region 11. The above steps simplify the patterning process for the initial first passivation contact structure 14.

[0131] In some embodiments, the ink layer 30 can be formed on the surface of the dielectric layer 20 in the metal pattern region 10 using any of screen printing, spraying, or 3D printing. The method for forming the ink layer 30 is relatively simple, and the pattern of the ink layer 30 can be easily controlled, which not only simplifies the patterning process of the dielectric layer 20, but also allows the precision of the pattern of the formed ink layer 30 to be precisely controlled, allowing the morphology of each film layer in the finally formed solar cell to meet expectations, and the photoelectric conversion performance of the solar cell to meet expectations.

[0132] In some embodiments, the method for pickling the dielectric layer 20 includes cleaning the surface of the dielectric layer 20 with either an HF solution or an HCl solution. The HF solution and the HCl solution are highly corrosive and can remove the dielectric layer 20 with high efficiency. In some embodiments, when the dielectric layer 20 is either borosilicate glass or phosphorus-containing silicon glass, the glass has relatively stable properties, so the concentration of the HF solution or the HCl solution needs to be controlled to be high. For example, the dielectric layer 20 not covered by the ink layer 30 can be removed with an HF solution having a mass concentration of 50% to 70%.

[0133] In some embodiments, a HF solution or an HCl solution can be sprayed onto the surface of the dielectric layer 20 to remove the dielectric layer 20 .

[0134] 12 and 14, the initial first passivation contact structure 14 and the initial surface 40 of the substrate 100 of the non-metal pattern region 11 are etched along the first opening 21 to form the substrate 100 surface of the non-metal pattern region 11 and the substrate 100 surface of the metal pattern region 10, wherein the substrate 100 surface of the non-metal pattern region 11 comprises adjacent first and second regions 12 and 13, the substrate 100 surface of the second region 13 is adjacent to the substrate 100 of the metal pattern region 10, the substrate 100 surface of the first region 12 is lower than the substrate 100 surface of the metal pattern region 10, and the substrate 100 surface of the second region 13 is neither lower than the substrate 100 surface of the first region 12 nor higher than the substrate 100 surface of the metal pattern region 10. The remaining initial first passivation contact structure 14 forms the first passivation contact structure 110.

[0135] In addition, the initial surface 40 of the substrate refers to the surface of the substrate 100 before etching the substrate 100 in the non-metallic pattern region 11, and the surface of the substrate 100 in the formed non-metallic pattern region 11 and the surface of the substrate 100 in the metal pattern region 10 refer to the surface of the substrate 100 formed after etching the substrate 100 in the non-metallic pattern region 11.

[0136] The first region 12, the second region 13, and the metal pattern region 10 of the non-metal pattern region 11 are successively adjacent to each other, and the height of the substrate 100 of the second region 13 is set to be between the height of the substrate 100 of the first region 12 and the height of the substrate 100 of the metal pattern region 10, so that the surfaces of the substrate 100 of the first region 12, the second region 13, and the metal pattern region 10 form a stepped structure. In this manner, after a doping process is performed on the surfaces of the substrate 100 of the first region 12 and the second region 13 to form a doped layer, the upper surface of the formed doped layer also has a stepped structure, which increases the surface area of ​​the doped layer compared to a flat surface, thereby improving the performance of the doped layer.

[0137] As shown in FIG. 14, in some embodiments, the surface of the substrate 100 in the second region 13 may be perpendicular to the surface of the substrate 100 in the first region 12 .

[0138] As shown in FIG. 12 , in some embodiments, the surface of the substrate 100 in the second region 13 may be inclined relative to the surface of the substrate 100 in the first region 12, and when the height difference between the surface of the substrate 100 in the first region 12 and the surface of the substrate 100 in the metal pattern region 10 is constant, the surface area of ​​the surface of the substrate 100 in the second region 13 can be increased, and the surface area of ​​the doping layer 120 later formed on the substrate 100 in the first region 12 and the second region 13 can be further increased.

[0139] In some embodiments, there is a first included angle θ between the surface of the substrate 100 in the first region 12 and the surface of the substrate 100 in the second region 13, and the first included angle θ may be between 90° and 160°, for example, between 90° and 95°, between 95° and 100°, between 100° and 105°, between 105° and 110°, between 110° and 115°, between 115° and 120°, between 120° and 125°, between 125° and 130°, between 130° and 135°, between 135° and 140°, between 140° and 145°, between 145° and 150°, between 150° and 155°, or between 155° and 160°.

[0140] In some embodiments, the height difference d between the surface of the substrate 100 in the metal pattern region 10 and the surface of the substrate 100 in the first region 12 is 0.1 μm to 10 μm, for example, 0.1 μm to 0.2 μm, 0.2 μm to 0.5 μm, 0.5 μm to 1 μm, 1 μm to 1.5 μm, 1.5 μm to 2 μm, 2 μm to 2.5 μm, 2.5 μm to 3 μm, 3 μm to 3.1 μm, 3.1 μm to 3.2 μm , 3.2 μm to 3.5 μm, 3.5 μm to 3.8 μm, 3.8 μm to 3.9 μm, 3.9 μm to 4 μm, 4 μm to 4.5 μm, 4.5 μm to 5 μm, 5 μm to 5.5 μm, 5.5 μm to 6 μm, 6 μm to 6.5 μm, 6.5 μm to 7 μm, 7 μm to 7.5 μm, 7.5 μm to 8 μm, 8 μm to 8.5 μm, 8.5 μm to 9 μm, or 9 μm to 10 μm. Within this range of height difference d, the height difference between the surface of substrate 100 in first region 12 and the surface of substrate 100 in metal pattern region 10 becomes large, imparting a large surface area to the surface of substrate 100 located in second region 13 and increasing the area of ​​doped layer 120, thereby improving the ability to generate photogenerated carriers when doped layer 120 is used as an emitter.

[0141] In some embodiments, a chemical etching process or a laser process may be used to etch the surface of the substrate 100 along the first opening 21 into the initial first passivation contact structure 14 and the non-metallic pattern region 11 .

[0142] In some embodiments, the method of etching the substrate 100 surface of the initial first passivation contact structure 14 and the non-metal pattern region 11 along the first opening 21 using a laser process may include laser processing the initial first passivation contact structure 14 to expose the substrate 100 surface of the non-metal pattern region 11. Subsequently, laser processing is performed on the exposed substrate 100 surface of the non-metal pattern region 11 to form a first region 12 and a second region 13 in the non-metal pattern region 11, and to form a step structure on the substrate 100 surface of the first region 12, the second region 13 and the metal pattern region 10.

[0143] In some embodiments, after etching the substrate 100 in the non-metallic pattern region 11, the substrate 100 in the non-metallic pattern region 11 may be textured to flatten the surface of the substrate 100 in the non-metallic pattern region 11. This helps to improve the flatness of the first passivation layer that is subsequently formed on the surface of the substrate 100 in the non-metallic pattern region 11.

[0144] In some embodiments, the surface of the substrate 100 in the metal pattern region 10 has a first texture structure, and the surface of the substrate 100 in the non-metal pattern region 11 has a second texture structure, and the roughness of the first texture structure is greater than the roughness of the second texture structure. By setting the roughness of the first texture structure to be large, the surface area of ​​the surface of the substrate 100 in the metal pattern region 10 can be increased, and further, the first passivation contact structure formed on the surface of the substrate 100 in the metal pattern region 10 can continue the morphology of the surface of the substrate 100 in the metal pattern region 10. Then, a large contact area can be provided between the first electrode formed on the first passivation contact structure and the first passivation contact structure, which reduces the contact resistance of the first electrode and improves the carrier transport performance.

[0145] In some embodiments, the first texture structure 1 may be a pyramid structure and the second texture structure may be a platform protrusion structure, as shown in Figure 13. In some embodiments, the pyramid structure may be a tetrahedron, an approximate tetrahedron, a pentahedron, or an approximate pentahedron, etc.

[0146] In some embodiments, before the step of forming the initial first passivation contact structure 14, a first texture structure 1 may be formed on the surface of the substrate 100, or the first texture structure 1 may be formed on the surface of the substrate 100 by a process such as chemical etching, mechanical etching, or laser etching.

[0147] In some embodiments, the second texture structure 2 may be a platform protrusion structure, which is the base of a pyramid structure, i.e., the bottom structure after removing the tip portion from the pyramid structure. In some embodiments, the second texture structure 2 may be a similar platform protrusion structure, the top surface of which may be a flat or inclined surface, and the bottom surface of which may be a polygonal plane, for example, a quadrilateral plane or a pentagonal plane.

[0148] In some embodiments, processes such as chemical etching, mechanical etching or laser etching may be employed to form the second texture structure 2 on the surface of the substrate 100 in the non-metallic pattern region 11 .

[0149] As shown in FIG. 15, a doping process is performed on the surface of the substrate 100 in the first region 12 and the second region 13 so as to form a doped layer 120 in the substrate 100.

[0150] In some embodiments, performing a doping process on the surface of the substrate 100 in the first region 12 and the second region 13 includes injecting a doping element into the surface of the substrate 100 in the first region 12 and the second region 13 to diffuse the doping element into the substrate 100 in the first region 12 and the second region 13 and form an initial doped layer 120 having a predetermined thickness, and performing an annealing process on the initial doped layer 120 to form the doped layer 120. Because the doped layer 120 is located on the substrate 100 in the first region 12 and the second region 13, the upper surface of the doped layer 120 has a stepped structure, which further increases the surface area of ​​the doped layer 120 and improves the performance of the doped layer 120.

[0151] As is apparent, the second region 13 is actually a transitional region between the first region 12 and the metal pattern region 10, and the presence of the second region 13 increases the area of ​​the doping layer 120. This eliminates the need to increase the surface area of ​​the doping layer 120 by creating a textured structure on the surface of the substrate 100 in the first region 12 of the non-metal pattern region 11, thereby flattening the surface of the substrate 100 in the first region 12. Forming the first passivation layer 140 on the surface of the substrate 100 in the first region 12 improves the flatness of the formed first passivation layer 140, thereby improving the passivation performance of the first passivation layer 140 relative to the surface of the substrate 100 and further enhancing the photoelectric conversion performance of the solar cell.

[0152] In some embodiments, the doping element concentration of the doped layer 120 may be smaller than the doping element concentration of the first doped conductive layer 112, so that the first doped conductive layer 112 forms a higher doping element concentration than the doped layer 120, and further forms a high-low junction with the doped layer 120, which can create a barrier effect for carriers in the doped layer 120 and enhance the lateral transport of carriers.

[0153] In some embodiments, the type of doping element in the doped layer 120 is different from the type of doping element in the substrate 100 and is the same as the type of doping element in the first doped conductive layer 112. That is, the doped layer 120 can act as an emitter and form a PN junction with the substrate 100. The PN junction can be used to receive incident light and generate photo-generated carriers, which are transported from the substrate 100 to the first doped conductive layer 112 and then to the first electrode 130, which is used to collect the photo-generated carriers. The photo-generated carriers can also be transported within the doped layer 120, from the doped layer 120 to the first doped conductive layer 112, and then collected by the first electrode 130.

[0154] As can be seen, the first doped conductive layer 112 also forms a PN junction with the substrate 100, and by using the first doped conductive layer 112 in the metal pattern region 10 to form a PN junction with the substrate 100, it is possible to reduce metal contact recombination between the first doped conductive layer 112 and the first electrode to be formed later, and improve the carrier collection ability of the first electrode. By forming the doped layer 120 for forming a PN junction on the substrate 100 in the non-metal pattern region 11, it is possible to significantly reduce parasitic absorption of incident light in the substrate 100 in the non-metal pattern region 11, and improve the utilization rate of the incident light.

[0155] In some embodiments, the doping element concentration of the doping layer 120 in the second region 13 gradually decreases in the direction from the side of the doping layer 120 in the first region 12 facing the first passivation contact structure 110 to the side of the doping layer 120 in the first region 12 away from the first passivation contact structure 110.

[0156] Since a part of a step structure is formed between the surface of the substrate 100 in the second region 13 and the surface of the substrate 100 in the first region 12, the surface of the substrate 100 in the second region 13 is perpendicular or inclined to the surface of the substrate 100 in the first region 12, i.e., the surface of the substrate 100 in the second region 13 has a difference in height in a direction perpendicular to the surface of the substrate 100 in the first region 12. This makes it possible to form a structure in which the doping element in the substrate 100 in the second region 13 is not uniform in a direction perpendicular to the surface of the substrate 100 in the first region 12 during the process of doping the surfaces of the substrate 100 in the first region 12 and the second region 13, and thus helps to form a structure in which the doping element concentration in the doped layer 120 in the second region 13 gradually changes, for example, a structure in which the doping element concentration in the doped layer 120 in the second region 13 gradually decreases in a direction of the first doped conductive layer 112 toward the doped layer 120 in the first region 12. In this way, the potential energy difference for carriers to transport between the doped layer 120 of the first region 12 and the first doped conductive layer 112 can be reduced, and the lateral transport ability of carriers can be further enhanced.

[0157] The dielectric layer 20 is removed.

[0158] In some embodiments, an acid cleaning process may be employed to remove some of the remaining dielectric layer 20, such as using an HF solution or an HCl solution to clean the remaining dielectric layer 20 and remove the remaining dielectric layer 20.

[0159] In some embodiments, when the ink layer 30 is formed on the surface of the dielectric layer 20 in the metal pattern region 10 so as to perform a patterning process on the dielectric layer 20, the ink layer 30 located on the surface of the dielectric layer 20 needs to be removed before the step of removing the dielectric layer 20. In some embodiments, the ink layer 30 located on the metal pattern region 10 is treated with an alkaline solution, which causes a saponification reaction with the ester groups in the ink, dissolving the ink and removing the ink layer 30. In some embodiments, the alkaline solution may be dropped onto the surface of the ink layer 30 by spraying, and the alkaline solution may be an NaOH solution or a KOH solution.

[0160] As shown in FIG. 16, in some embodiments, the method further includes forming a second passivation contact structure 150 on a surface of the substrate 100 farther from the first passivation contact structure 110, and the second passivation contact structure 150 may include at least one second tunnel layer 151 and at least one second doped conductive layer 152 stacked sequentially along a direction farther from the substrate 100.

[0161] In some embodiments, the second passivation contact structure 150 may include only one second tunnel layer 151 and one second doped conductive layer 152 stacked along a direction away from the substrate 100.

[0162] In some embodiments, the second passivation contact structure 150 may further include multiple sub-second passivation contact structures stacked along a direction away from the substrate 100, each of which includes a second tunnel layer 151 and a second doped conductive layer 152 stacked along a direction away from the substrate 100.

[0163] In some embodiments, the method for forming the second tunnel layer 151 may refer to the above description of the method for forming the initial first tunnel layer 15, and the method for forming the second doped conductive layer 152 may refer to the above description of the method for forming the initial first doped conductive layer 16. The difference lies in that the type of doping element in the second doped conductive layer 152 is different from the type of doping element in the formed first doped conductive layer 112.

[0164] 17 , in some embodiments, the method further includes forming a first passivation layer 140 on the upper surface of the doping layer 120 and the upper and side surfaces of the first passivation contact structure 110. The first passivation layer 140 can provide good passivation effect, suppress carrier recombination, and increase carrier concentration. In some embodiments, the first passivation layer 140 can have a single-layer structure. In other embodiments, the first passivation layer 140 can have a multi-layer structure. In some embodiments, the material of the first passivation layer 140 can be at least one of silicon oxide, aluminum oxide, silicon nitride, or silicon oxynitride.

[0165] In some embodiments, the method of forming the first passivation layer 140 may include forming the first passivation layer 140 on the top surface of the doping layer 120 and on the top and side surfaces of the first passivation contact structure 110 using a PECVD method (Plasma Enhanced Chemical Vapor Deposition).

[0166] In some embodiments, the method further includes forming a second passivation layer 160, which can exhibit good passivation effect, on the surface of the second doped conductive layer 152. In some embodiments, the second passivation layer 160 may have a single-layer structure, and in other embodiments, the second passivation layer 160 may have a multi-layer structure. In some embodiments, the material of the second passivation layer 160 may be at least one of silicon oxide, aluminum oxide, silicon nitride, or silicon oxynitride.

[0167] In some embodiments, the second passivation layer 160 may be formed using a PECVD process.

[0168] As shown in FIG. 1, some embodiments may further include forming a first electrode 130 that penetrates the first passivation layer 140 and is in electrical contact with the first doped conductive layer 112, and the first passivation contact structure 110 is placed only on the surface of the substrate 100 in the metal pattern region 10, and the first electrode 130 is in electrical contact with the first doped conductive layer 112, thereby reducing metal contact recombination between the first passivation contact structure 110 and the metal electrode and improving the carrier collection ability of the metal electrode.

[0169] In some embodiments, a method for forming the first electrode 130 includes printing a conductive paste on the surface of the first passivation layer 140 in the metal pattern region 10. For example, the conductive paste may be printed using a screen printing process, and the conductive paste may include at least one of silver, aluminum, copper, tin, gold, lead, or nickel. The conductive paste on the surface of the first passivation layer 140 is sintered to allow the conductive paste to penetrate the first passivation layer 140 and a portion of the first doped conductive layer 112 and make electrical contact with the first doped conductive layer 112.

[0170] In some embodiments, the method further includes forming a second electrode 170 through the second passivation layer 160 and in electrical contact with the second doped conductive layer 152. In some embodiments, the process for forming the second electrode 170 may be the same as the process for forming the first electrode 130, and reference may be made to the above description of the method for forming the first electrode 130.

[0171] Although the present application has been disclosed as above in preferred embodiments, it does not limit the scope of the claims, and any person skilled in the art can make some possible variations and modifications without departing from the idea of ​​the present application, so the protection scope of the present application should be in accordance with the scope defined by the claims of the present application.

[0172] Those skilled in the art will understand that the above embodiments are specific examples of realizing the present application, but that various changes in form and details are possible in practice without departing from the spirit and scope of the present application. Since anyone skilled in the art can make changes and modifications without departing from the spirit and scope of the present application, the scope of protection of the present application should be based on the scope limited by the claims.

Claims

1. a substrate having a first electrode, a metal pattern region and a non-metal pattern region on a surface thereof, a doping layer, a first passivation contact structure covering the substrate surface in the metal pattern region, and a second passivation contact structure located on a surface of the substrate remote from the first passivation contact structure; the first electrode is provided in the metal pattern region, the non-metal pattern region does not include the first electrode, the non-metal pattern region includes adjacent first and second regions, the side of the second region farther from the first region is adjacent to the metal pattern region, the height of the substrate surface of the first region is lower than the height of the substrate surface of the metal pattern region, the height of the substrate surface of the second region is not lower than the height of the substrate surface of the first region and not higher than the height of the substrate surface of the metal pattern region, the doped layer is a substrate surface layer in the first region and the second region, the first passivation contact structure includes at least one first tunnel layer and at least one first doped conductive layer stacked together; the second passivation contact structure includes at least one second tunnel layer and at least one second doped conductive layer stacked together; a first included angle between the substrate surface in the first region and the substrate surface in the second region, the first included angle being between 90° and 160°; A solar cell characterized by:

2. the doping element of the first doped conductive layer and the doping element of the doped layer are of the same group; The solar cell according to claim 1 .

3. the doping element concentration of the first doped conductive layer is equal to or greater than the doping element concentration of the doped layer; The solar cell according to claim 2 .

4. The doping element concentration of the first doped conductive layer is 1×10 １９ atoms / cm ３ ~9 x 10 ２０ atoms / cm ３ and the doping element concentration of the doped layer is 1×10 １６ atoms / cm ３ ~1 x 10 ２０ atoms / cm ３ That is, The solar cell according to claim 3 .

5. The type of doping element in the doped layer is different from the type of doping element in the substrate; The solar cell according to claim 3 .

6. The doping layer has a doping element concentration greater than that of the substrate; The solar cell according to claim 5 .

7. The doping element concentration of the doping layer in the second region is not less than the doping element concentration of the doping layer in the first region and not greater than the doping element concentration of the first doped conductive layer; The solar cell according to claim 1 .

8. a doping element concentration of the doped layer in the second region gradually decreases in a direction from a side of the doped layer in the first region toward the first doped conductive layer toward a side of the doped layer in the first region away from the first doped conductive layer; The solar cell according to claim 7 .

9. The difference between the doping concentration of the surface of the doped layer in the second region facing the first doped conductive layer and the doping concentration of the surface of the doped layer in the second region facing away from the first doped conductive layer is 1×10 １９ atoms / cm ３ ~8 x 10 ２０ atoms / cm ３ That is, The solar cell according to claim 8 .

10. the sheet resistance of the doped layer is 80 ohm / sq to 1000 ohm / sq; The solar cell according to claim 8 .

11. a height difference between the substrate surface of the metal pattern region and the substrate surface of the first region is 0.1 μm to 10 μm; The solar cell according to claim 1 .

12. the first passivation contact structure includes a plurality of sub-first passivation contact structures stacked along a direction away from the substrate, and each of the sub-first passivation contact structures includes the first tunnel layer and the first doped conductive layer stacked along a direction away from the substrate; The solar cell according to claim 1 .

13. a first passivation layer disposed on an upper surface of the doping layer and on an upper surface and a side surface of the first passivation contact structure; The solar cell according to claim 1 .

14. the first electrode passes through the first passivation layer and is electrically connected to the first doped conductive layer; The solar cell according to claim 13 .

15. a battery string formed by connecting a plurality of solar cells according to any one of claims 1 to 14; a sealing layer used to cover the surface of the battery string; a cover plate used to cover a surface of the sealing layer away from the battery string; A photovoltaic module characterized by:

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