Solar cell and method for manufacturing solar cell

Abstract

Provided in the present application are a solar cell and a method for manufacturing a solar cell. The solar cell comprises: a substrate, which has a first surface and a second surface that are opposite each other, wherein the second surface has a first region and a second region that are adjacent to each other in a first direction; a tunneling layer and a first doped layer, which are sequentially arranged below the first region; a first insulating layer, which is arranged below the first doped layer; a second doped layer, which is arranged below the second region; a plurality of contact holes, wherein each contact hole penetrates through the first insulating layer and exposes the first doped layer; and a first grid line, wherein at least part of the first grid line is located in the contact holes, and the first grid line is electrically connected to the first doped layer. In the solar cell and the method for manufacturing a solar cell of the present application, the first grid line is in contact with the first doped layer by means of the contact holes, such that the area of contact between the first grid line and the first doped layer can be reduced, thereby reducing metal-semiconductor composite loss, and thus improving the efficiency of the solar cell.

Description

Solar cell and method for manufacturing solar cell Technical Field

[0001] The present application mainly relates to the field of photovoltaic technology, and in particular to a solar cell and a method for manufacturing a solar cell. Background Art

[0002] Solar cells can convert solar energy into electrical energy, and compared to non-renewable energy generation, they have the advantage of being pollution-free. Currently, the main types of solar cells include Passivated Emitter and Rear Contact (PERC), Tunnel Oxide Passivated Contact (TOPCON), Hetero-Junction with Intrinsic Thin Film (HIT), and Interdigitated Back Contact (IBC). Although the photoelectric conversion efficiency of solar cells has been continuously improved with the development of solar cell technology, the photovoltaic field has been developing solar cells with higher photoelectric conversion efficiency.

[0003] Summary of the Invention

[0004] The technical problem to be solved by the present application is to provide a solar cell and a method for manufacturing the solar cell, which can reduce metal-semiconductor composite loss and thereby improve the efficiency of the solar cell.

[0005] The technical solution adopted by the present application to solve the above-mentioned technical problems is a solar cell, comprising: a substrate having a first surface and a second surface relative to each other, the second surface having a first region and a second region adjacent to each other in a first direction; a tunneling layer and a first doping layer, sequentially arranged below the first region; a first insulating layer, arranged below the first doping layer; a second doping layer, arranged below the second region; a plurality of contact holes, each of the contact holes penetrating the first insulating layer and exposing the first doping layer; and a first gate line, at least a portion of the first gate line being located within the contact hole, the first gate line being electrically connected to the first doping layer.

[0006] In one embodiment of the present application, the contact hole penetrates deep into the first doping layer.

[0007] In an embodiment of the present application, the cross-section of the contact hole includes a circle, an ellipse or a rectangle.

[0008] In one embodiment of the present application, the first gate line includes a second contact portion and multiple first contact portions, each of the first contact portions is located in a corresponding contact hole, one end of each first contact portion is in direct contact with the first doped layer, and the other end is in direct contact with the second contact portion.

[0009] In an embodiment of the present application, the width of each first contact portion is smaller than the width of the second contact portion.

[0010] In one embodiment of the present application, the second contact portion is located outside the contact hole.

[0011] In one embodiment of the present application, a first passivation layer is further provided in the second region and extends to the surface of the first insulating layer away from the substrate, wherein the second doping layer is provided on the surface of the first passivation layer away from the substrate.

[0012] In one embodiment of the present application, a second insulating layer is further included, which is arranged between the first passivation layer, the first doping layer and the tunneling layer along the first direction, and the side of the second insulating layer away from the substrate is in contact with the first insulating layer.

[0013] In one embodiment of the present application, a transparent conductive layer is further included, which is formed on a surface of the second doped layer away from the substrate.

[0014] In one embodiment of the present application, a second gate line is further included, which is electrically connected to the transparent conductive layer located in the second area.

[0015] In one embodiment of the present application, a first isolation trench and a second isolation trench are further included. The first isolation trench and the second isolation trench are arranged on both sides of the first gate line along the first direction and penetrate the transparent conductive layer corresponding to the first region.

[0016] In one embodiment of the present application, the transparent conductive layer is also formed on the sidewalls and bottom of the contact hole, wherein the first gate line located in the contact hole is electrically connected to the first doped layer through the transparent conductive layer located on the bottom of the contact hole.

[0017] In another aspect, the present application provides a method for manufacturing a solar cell, comprising: providing a substrate, the substrate having a first surface and a second surface opposite to each other, the second surface having a first region and a second region adjacent to each other in a first direction; forming a tunneling layer and a first doping layer in sequence below the first region; forming a first insulating layer below the first doping layer; forming a second doping layer below the second region; forming a plurality of contact holes penetrating the first insulating layer and exposing the first doping layer; and

[0018] A first gate line is formed, wherein at least a portion of the first gate line is located in the contact hole, and the first gate line is electrically connected to the first doped layer.

[0019] In one embodiment of the present application, after the step of forming the multiple contact holes, a transparent conductive layer is formed, wherein the transparent conductive layer covers the surface of the second doped layer away from the substrate, and covers the sidewalls of the contact holes and the first doped layer exposed by the contact holes.

[0020] In one embodiment of the present application, after the step of forming the transparent conductive layer, a first isolation trench and a second isolation trench are formed, wherein the first isolation trench and the second isolation trench are located on both sides of the first gate line and penetrate the transparent conductive layer.

[0021] In one embodiment of the present application, a second gate line is formed, the first gate line is in direct contact with the transparent conductive layer located in the contact hole, and the second gate line is electrically connected to the transparent conductive layer located in the second region.

[0022] The first gate line in the solar cell and the solar cell manufacturing method of the present application contacts the first doped layer through the contact hole, which can reduce the contact area between the first gate line and the first doped layer, thereby reducing metal-semiconductor composite loss and improving the efficiency of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to make the above-mentioned objects, features and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings, wherein:

[0024] FIG1 is a partial top view of a solar cell according to an embodiment of the present application;

[0025] FIG2 is a schematic cross-sectional view of the solar cell along line AA in FIG1 ;

[0026] FIG3 is a schematic cross-sectional view of the solar cell along line BB in FIG1 ;

[0027] 4 and 5 are schematic cross-sectional views of a solar cell according to another embodiment of the present application;

[0028] FIG6 is a schematic flow chart of a method for manufacturing a solar cell according to an embodiment of the present application;

[0029] 7 to 14 are schematic cross-sectional views of a solar cell during the manufacturing process of the solar cell;

[0030] 15 to 17 illustrate a method for forming a first gate line according to an embodiment. DETAILED DESCRIPTION

[0031] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below with reference to the accompanying drawings.

[0032] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0033] As used in this application and the claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not intended to refer to the singular but may include the plural. Generally speaking, the terms "comprises" and "include" only indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list. A method or apparatus may also include other steps or elements.

[0034] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is solely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. Furthermore, while the terms used in this application are selected from commonly known and commonly used terms, some terms mentioned in this specification may have been selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant sections of this description. Furthermore, this application should be understood not only by the actual terms used, but also by the meaning implied by each term.

[0035] Flowcharts are used in this application to illustrate the operations performed by systems according to embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, the various steps may be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0036] Next, the solar cell and solar cell sheet of the present application are described through specific embodiments.

[0037] Figure 1 is a partial top view of a solar cell according to one embodiment, Figure 2 is a cross-sectional view of the solar cell along line AA in Figure 1 , and Figure 3 is a cross-sectional view of the solar cell along line BB in Figure 1 . Referring to Figures 1 to 3 , the solar cell includes a substrate 110, a tunneling layer 170, a first doped layer 160, a first insulating layer 180, a second doped layer 230, a contact hole 250, and a first gate line 260.

[0038] Specifically, the substrate 110 has a first surface 111 and a second surface 112 opposite to each other in the thickness direction D3. The second surface 112 has a first region 112a and a second region 112b adjacent to each other in the first direction D1. When the solar cell is in operation, the first surface 111 serves as the side of the solar cell that receives light.

[0039] The substrate 110 may be single crystal silicon. After doping, the substrate 110 may be either n-type single crystal silicon or p-type single crystal silicon. When the substrate 110 is n-type single crystal silicon, the doping element may be phosphorus (P) and / or arsenic (As). When the substrate 110 is p-type single crystal silicon, the doping element may be boron (B) and / or gallium (Ga).

[0040] The tunneling layer 170 and the first doping layer 160 are sequentially arranged below the first region 112a. Specifically, the tunneling layer 170 is formed in the first region 112a, and the first doping layer 160 is formed on the surface of the tunneling layer 170 away from the substrate 110. The tunneling layer 170 can be selected from silicon oxide (SiO x ), silicon oxynitride (SiO y N x ) and aluminum oxide (Al2O3). The thickness of tunneling layer 170 is equal to or less than 3 nm, for example, 1 nm, 1.5 nm, 2 nm, or 2.5 nm. In some embodiments, tunneling layer 170 contains the same doping element as that in substrate 110 and / or first doping layer 160.

[0041] The first doped layer 160 may be doped polysilicon, which may contain one or more of oxygen (O), carbon (C), and nitrogen (N). The doping type of the first doped layer 160 may be the same as that of the substrate 110, or may be opposite to that of the substrate 110. In some embodiments, the thickness of the first doped layer 160 is equal to or greater than 20 nm and equal to or less than 600 nm, for example, 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, or 550 nm. The first doped layer 160 has a passivation effect on the solar cell.

[0042] In some embodiments, the solar cell further includes a second diffusion layer 150. The second diffusion layer 150 is formed in the first region 112a. The second diffusion layer 150 may be crystalline silicon (single crystal silicon and / or polycrystalline silicon), and the doping type of the second diffusion layer 150 may be the same as or opposite to that of the substrate 110. This application does not limit the doping concentration of the second diffusion layer 150. The doping concentration of the second diffusion layer 150 may be equal to or less than the doping concentration of the first doping layer 160, or may be greater than the doping concentration of the first doping layer 160, or may be greater than the doping concentration of the substrate 110. In some embodiments, the second diffusion layer 150 may be formed by diffusing doping elements from the first doping layer 160 into the substrate 110 during the step of forming the first doping layer 160.

[0043] In the case where the solar cell includes the second diffusion layer 150, the tunneling layer 170 and the first doping layer 160 are sequentially formed on a surface of the second diffusion layer 150 that is away from the substrate 110 in the thickness direction D3. That is, as shown in FIG2 , the second diffusion layer 150, the tunneling layer 170, and the first doping layer 160 are sequentially stacked in the first region 112a along the thickness direction D3.

[0044] The first insulating layer 180 is located on a surface of the first doped layer 160 that is away from the substrate 110 in the thickness direction D3. The first insulating layer 180 may include one or more of silicon oxide, silicon nitride (SiN), and silicon oxynitride. The first insulating layer 180 may contain the same doping elements as those in the first doped layer 160. These doping elements in the first insulating layer 180 may be intentionally added through a specific process, or may be diffused from the doping elements in the first doped layer 160 into the first insulating layer 180.

[0045] The second doped layer 230 is located below the second region 112b. The second doped layer 230 may be doped amorphous silicon and / or microcrystalline silicon. The doped amorphous silicon and microcrystalline silicon may include one or more of oxygen, carbon, and nitrogen. The thickness of the second doped layer 230 may be any value within the range of 3 nm to 60 nm. The doping type of the second doped layer 230 is opposite to that of the first doped layer 160.

[0046] In one embodiment, the solar cell further includes a first passivation layer 210. The first passivation layer 210 is disposed in the second region 112b and extends to a surface of the first insulating layer 180 that is away from the substrate 110 in the thickness direction D3. When the solar cell includes the first passivation layer 210, the second doping layer 230 is disposed on a surface of the first passivation layer 210 that is away from the substrate 110 in the thickness direction D3.

[0047] As shown in Figure 2, the first insulating layer 180 is arranged between the first passivation layer 210 and the first doping layer 160 in the thickness direction D3. In this way, the first insulating layer 180 can isolate the first passivation layer 210 and the first doping layer 160 in the thickness direction D3, thereby preventing the first passivation layer 210 from contacting the first doping layer 160 and causing a short-circuit current to occur between the first gate line 260 and the second gate line 270.

[0048] In one embodiment, the solar cell further includes a second insulating layer 190. The second insulating layer 190 is located between the first passivation layer 210 and the first doped layer 160 in the first direction D1, and is also located between the first passivation layer 210 and the tunneling layer 170. The second insulating layer 190 contacts the first insulating layer 180 on the side away from the substrate 110 in the thickness direction D3. If the solar cell includes a second diffusion layer 150, the second insulating layer 190 is also located between the first passivation layer 210 and the second diffusion layer 150 in the first direction D1. The second insulating layer 190 can isolate the second diffusion layer 150, the first doped layer 160, and the tunneling layer 170 from the first passivation layer 210 in the first direction D1, thereby further preventing short-circuit current from occurring between the first gate line 260 and the second gate line 270. It should be noted that even if the solar cell does not include the second insulating layer 190, short-circuit current can still be effectively prevented between the first gate line 260 and the second gate line 270. The reason is as follows: when the solar cell does not have the second insulating layer 190, the surfaces of the second diffusion layer 150, the first doping layer 160 and the tunneling layer 170 close to the second gate line 270 in the first direction D1 are in contact with the first passivation layer 210, but since the second diffusion layer 150, the first doping layer 160 and the tunneling layer 170 are relatively thin, the area of ​​the contact surface between the second diffusion layer 150, the first doping layer 160 and the tunneling layer 170 and the first passivation layer 210 is relatively small, and it is difficult for current to pass through the above-mentioned contact surface.

[0049] In one embodiment, the material of the second insulating layer 190 may be the same as or different from that of the first insulating layer 180. The first insulating layer 180 and the second insulating layer 190 may be formed in the same process step. The thickness of the first insulating layer 180 and the second insulating layer 190 is equal to or greater than 1.5 nm. The thickness of the first insulating layer 180 and the second insulating layer 190 may be equal or different.

[0050] In one embodiment, the solar cell further includes a transparent conductive layer 240. The transparent conductive layer 240 is formed on a surface of the second doped layer 230 that is away from the substrate 110 in the thickness direction D3. The transparent conductive layer 240 can be selected from one or more of zinc oxide (ZnO), indium oxide (InO), and tin oxide (SnO). The transparent conductive layer 240 can contain one or more of gallium (Ga), tin (Sn), molybdenum (Mo), cerium (Ce), fluorine (F), tungsten (W), and aluminum (Al).

[0051] Continuing with reference to Figures 1 to 3 , the solar cell has a plurality of contact holes 250 spaced apart in the second square D2. Due to the limited size of the drawings, only two contact holes 250 are shown in Figures 1 and 3 . It should be noted that the contact holes 250 cannot be seen in Figure 1 ; the contact holes 250 in Figure 1 are only used to illustrate the locations of the contact holes 250.

[0052] 3 , the contact hole 250 penetrates the first insulating layer 180 and exposes the first doped layer 160. It will be understood that when the surface of the first insulating layer 180 away from the substrate 110 is covered with other material layers (e.g., the first passivation layer 210, the second doped layer 230, and the transparent conductive layer 240), the contact hole 250 also penetrates these material layers.

[0053] Referring to Figures 1 to 3, the first gate line 260 includes a second contact portion 262 and a plurality of first contact portions 261. The first contact portion 261 is located in the corresponding contact hole 250, and the second contact portion 262 is located outside the contact hole 250. One end of each first contact portion 261 is electrically connected to the first doped layer 160, and the other end is in direct contact with the second contact portion 262. The width of the first contact portion 261 (the dimension in the first direction D1) is smaller than the width of the second contact portion 262 (the dimension in the first direction D1). In other embodiments, the width of the first contact portion 261 may also be equal to or greater than the width of the second contact portion 262. For ease of understanding in Figure 3, the first gate line 260 in the left contact hole 250 is not shown. The first gate line 260 can be a metal containing silver or a metal containing copper.

[0054] The contact hole 250 may not extend deep into the first doped layer 160, that is, the contact hole 250 exposes the surface of the first doped layer 160 away from the substrate 110. In this case, the first contact portion 261 is in direct contact with the surface of the first doped layer 160 away from the substrate 110. The contact hole 250 may also extend deep into the first doped layer 160, that is, the contact hole 250 exposes the interior of the first doped layer 160. In this case, the first contact portion 261 is in direct contact with the interior of the first doped layer 160. Providing the contact hole 250 deep into the first doped layer 160 can increase the process window for forming the contact hole 250.

[0055] 1 and 3 , the cross section of the contact hole 250 is circular. In other embodiments, the cross section of the contact hole 250 may also be elliptical or rectangular. The cross sections of the contact holes 250 may have the same or different shapes.

[0056] The direct contact between the first gate line 260 and the first doped layer 160 may introduce metal-semiconductor composite loss (J 0，metal ), thereby reducing the efficiency of the solar cell. The first gate line 260 directly contacts the first doped layer 160 through the contact hole 250. Compared with contacting the first doped layer 160 through the trench, contacting through the contact hole 250 can reduce the contact area between the first gate line 260 and the first doped layer 160, thereby reducing metal-semiconductor recombination losses and improving the efficiency of the solar cell.

[0057] 1 to 3 , the solar cell further includes a second gridline 270. The second gridline 270 is located in the second region 112 b and is electrically connected to the transparent conductive layer 240. The second gridline 270 may be in direct contact with the transparent conductive layer 240 located in the second region 112 b. The second gridline 270 may be made of a metal containing silver or a metal containing copper.

[0058] 2 , in one embodiment, the solar cell further includes a first isolation trench 280 and a second isolation trench 290. The first isolation trench 280 and the second isolation trench 290 are disposed on both sides of the first gate line 260 along the first direction D1, and both the first isolation trench 280 and the second isolation trench 290 penetrate the transparent conductive layer 240, the second doped layer 230, and the first passivation layer 210 located in the first region 112a. The first isolation trench 280 and the second isolation trench 290 can isolate the transparent conductive layer 240, the second doped layer 230, and the first passivation layer 210, thereby achieving electrical isolation between the first gate line 260 and the adjacent second gate line 270, thereby preventing the transparent conductive layer 240, the second doped layer 230, and the first passivation layer 210 from connecting the first gate line 260 and the second gate line 270, thereby preventing a short circuit between the adjacent electrodes.

[0059] In some other embodiments, the first isolation trench 280 and the second isolation trench 290 may extend deep into the first doping layer 160 along the thickness direction D3 and may not penetrate the first doping layer 160. In some other embodiments, the first isolation trench 280 and the second isolation trench 290 may only penetrate the transparent conductive layer 240.

[0060] Figures 4 and 5 are schematic cross-sectional views of a solar cell in another embodiment. The main difference between the solar cell in Figures 4 and 5 and the solar cell in Figures 1 to 3 is that the transparent conductive layer 240 is also formed on the sidewalls and bottom surface of the contact hole 250, and the transparent conductive layer located on the bottom surface covers the first doped layer exposed by the contact hole. The first gate line 260 (i.e., the first contact portion 261) located in the contact hole 250 is not in direct contact with the first doped layer 160. The first gate line 260 in the contact hole 250 is in indirect contact with the first doped layer 160 through the transparent conductive layer 240 located on the bottom surface of the contact hole 250, and is electrically connected to the first doped layer 160 through this indirect contact. In other words, a transparent conductive layer 240 is provided between the first contact portion 261 and the sidewalls of the contact hole 250, and between the first contact portion 261 and the bottom surface of the contact hole 250. Indirect contact can avoid direct contact between the first gate line 260 and the first doped layer 260, thereby avoiding the introduction of metal-semiconductor composite loss (J 0，metal ).

[0061] During the process of forming the transparent conductive layer 240, the process used to form the transparent conductive layer 240 (e.g., physical vapor deposition (PVD)) can damage the first doped layer 160 exposed by the contact hole 250. Conventional techniques use trenches to expose the first doped layer 160, and then form the first gate line 260 within the trenches. Compared to trenches, the area of ​​the first doped layer 160 exposed by the contact hole 250 is smaller. Therefore, the damage caused to the exposed first doped layer 160 by the process of forming the transparent conductive layer 240 can be reduced, thereby improving the open-circuit voltage of the solar cell.

[0062] As shown in Figures 2 and 3, in one embodiment, the solar cell further includes a first diffusion layer 120. The first diffusion layer 120 is located on the first surface 111 of the substrate 110. The first diffusion layer 120 may be crystalline silicon (single crystal silicon and / or polycrystalline silicon). The doping type of the first diffusion layer 120 may be the same as that of the substrate 110, or may be opposite to that of the substrate 110. The doping concentration of the first diffusion layer 120 may be equal to or greater than the doping concentration of the substrate 110. The thickness of the first doping layer 120 may be any value within the range of 10 nm to 1500 nm.

[0063] In one embodiment, the solar cell further includes a second passivation layer 130 and an anti-reflection layer 140. The second passivation layer 130 and the anti-reflection layer 140 are sequentially disposed on a surface of the first diffusion layer 120 away from the substrate 110 along the thickness direction D3. The second passivation layer 130 can be selected from intrinsic amorphous silicon, amorphous silicon containing one or more of oxygen, carbon, and nitrogen, silicon oxide, silicon oxynitride, or aluminum oxide. The second passivation layer 130 has a passivating effect, thereby improving the efficiency of the solar cell. In one embodiment, the thickness of the second passivation layer 130 is equal to or greater than 1.5 nm.

[0064] The anti-reflection layer 140 can be made of dielectric materials such as silicon oxide and silicon oxynitride. The thickness of the anti-reflection layer 140 is equal to or greater than 40 nm. Forming the anti-reflection layer 140 on the side where the first surface 111 is located can increase the absorption of incident light by the solar cell, thereby improving the utilization rate of the incident light by the solar cell. In some embodiments, the first surface 111 has a pyramid velvet morphology. The first diffusion layer 120, the second passivation layer 130 and the anti-reflection layer 140 sequentially formed on the first surface 111 also have a pyramid velvet morphology. When the solar cell is working, the pyramid velvet morphology can trap light and reduce the reflection of incident light, thereby improving the utilization rate of light by the solar cell.

[0065] In some embodiments, the solar cell 100 may not include the first diffusion layer 120 , and the second passivation layer 130 is formed on the first surface 111 of the substrate 110 .

[0066] In one embodiment, the first passivation layer 210 may be intrinsic amorphous silicon, which may contain one or more of oxygen, carbon, and nitrogen. These elements are beneficial for improving the passivation effect of the first passivation layer 210 while reducing optical absorption loss. The thickness of the first passivation layer 210 may be anywhere from 3 nm to 15 nm.

[0067] The present application also provides a method for manufacturing a solar cell. Referring to FIG6 , which is a flow chart of a method for manufacturing a solar cell according to an embodiment, the embodiment includes the following steps:

[0068] Step S310: providing a substrate, wherein the substrate has a first surface and a second surface opposite to each other, wherein the second surface has a first region and a second region adjacent to each other in a first direction;

[0069] Step S320: forming a tunneling layer and a first doping layer in sequence below the first region;

[0070] Step S330: forming a first insulating layer below the first doped layer;

[0071] Step S340: forming a second doping layer below the second region;

[0072] Step S350: forming a plurality of contact holes penetrating the first insulating layer and exposing the first doped layer;

[0073] Step S360: forming a first gate line, wherein at least a portion of the first gate line is located in the contact hole, and the first gate line is electrically connected to the first doped layer.

[0074] 7 to 14 are schematic cross-sectional views of a solar cell during the manufacturing process of the solar cell. Steps S310 to S360 are described with reference to FIG7 to 14.

[0075] 7 , in step S310 , a substrate 110 is provided. The substrate 110 has a first surface 111 and a second surface 112 opposite to each other. The second surface 112 has a first region 112 a and a second region 112 b adjacent to each other in a first direction D1 .

[0076] 7 to 10 , in step S320 , a tunneling layer 170 and a first doping layer 160 are sequentially formed in the first region 112 a .

[0077] Specifically, as shown in Figures 8 and 9 , a first diffusion layer 120 is formed on the first surface 111 of the substrate 110, and an initial second diffusion layer 150-1, an initial tunneling layer 170-1, an initial first doping layer 160-1, and an initial first insulating layer 180-1 are sequentially formed on the second surface 112. In some embodiments, the first diffusion layer 120 and the initial second diffusion layer 150-1 may not be formed.

[0078] Next, referring to Figures 9 and 10, the initial second diffusion layer 150-1, the initial tunneling layer 170-1, the initial first doping layer 160-1 and the initial first insulating layer 180-1 in the second region 112b are removed, and the initial second diffusion layer 150-1, the initial tunneling layer 170-1, the initial first doping layer 160-1 and the initial first insulating layer 180-1 in the first region 112a are retained. The retained initial second diffusion layer 150-1, the initial tunneling layer 170-1, the initial first doping layer 160-1 and the initial first insulating layer 180-1 become the second diffusion layer 150, the tunneling layer 170, the first doping layer 160 and the first insulating layer 180, respectively.

[0079] 10 , in one embodiment, a second insulating layer 190 may be further formed on the side surfaces of the second diffusion layer 150 , the tunneling layer 170 , and the first doping layer 160 .

[0080] 10 and 11 , in step S340, a second doped layer 230 is formed below the second region 112 b, and the second doped layer 230 extends to the first region 112 a. Specifically, the second doped layer 230 in FIG11 is formed on a surface of the first passivation layer 210 that is distal from the substrate 110 in the thickness direction D3. The first passivation layer 210 is formed in the second region 112 b and extends to a surface of the first insulating layer 180 distal from the substrate 110. In other embodiments, the solar cell may not include the first passivation layer 210, and the second doped layer 230 may be formed in the second region 112 b and extend to a surface of the first insulating layer 180 distal from the substrate 110.

[0081] 12 , in one embodiment, a transparent conductive layer 240 may be further formed on a surface of the second doping layer 230 away from the substrate 110 .

[0082] 12 and 13 , in step S350 , a contact hole 250 is formed through the first insulating layer 180 and exposes the first doping layer 160 .

[0083] 13 , in one embodiment, a first isolation trench 280 and a second isolation trench 290 are formed simultaneously with the contact hole 250 , wherein the first isolation trench 280 and the second isolation trench 290 are located on both sides of the contact hole 250 .

[0084] 13 and 14 , in step S360, a first gate line 260 is formed, at least a portion of the first gate line 260 is located within the contact hole 250, and the first gate line 260 is electrically connected to the first doped layer 160. A second gate line 270 may also be formed simultaneously with the formation of the first gate line 260, and the second gate line 270 is electrically connected to the transparent conductive layer 240 located below the second region.

[0085] The direct contact between the first gate line 260 and the first doped layer 160 may introduce metal-semiconductor composite loss (J 0，metal ), thereby reducing the efficiency of the solar cell. The first gate line 260 contacts the first doped layer 160 through the contact hole 250. Compared with contacting the first doped layer 160 through the groove, the contact method of the present application reduces the contact area between the first gate line 260 and the first doped layer 160, thereby reducing metal-semiconductor recombination losses and improving the efficiency of the solar cell.

[0086] Figures 15 to 17 show another method for forming a first gate line. Referring to Figure 15, a contact hole 250 is formed that penetrates the first insulating layer 180 and exposes the first doping layer 160; then, referring to Figure 16, a transparent conductive layer 240 is formed. The transparent conductive layer 240 covers the surface of the second doping layer 230 away from the substrate 110 and covers the sidewalls and bottom surface of the contact hole 250; then, a first isolation trench 280 and a second isolation trench 290 are formed. The first isolation trench 280 and the second isolation trench 290 both penetrate the transparent conductive layer 240; then, referring to Figures 16 and 17, a first gate line 260 is formed in the contact hole 250. The first gate line 260 is indirectly in contact with the first doping layer 160 through the transparent conductive layer in the contact hole 250. The first gate line 260 is electrically connected to the first doping layer 160 through the above-mentioned indirect contact. The indirect contact can avoid direct contact between the first gate line 260 and the first doping layer 160, thereby avoiding the introduction of metal-semiconductor composite loss (J 0，metal ).

[0087] For other details about the manufacturing method of the present application, please refer to the above description of the solar cell, which will not be elaborated here.

[0088] The basic concepts have been described above. It will be apparent to those skilled in the art that the above disclosures are merely examples and do not limit the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and revisions to the present application. Such modifications, improvements, and revisions are suggested in the present application and remain within the spirit and scope of the exemplary embodiments of the present application.

[0089] At the same time, this application uses specific terms to describe the embodiments of this application. For example, "one embodiment," "an embodiment," and / or "some embodiments" refer to a certain feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that "one embodiment," "an embodiment," or "an alternative embodiment" mentioned twice or multiple times in different locations in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application may be appropriately combined.

[0090] In some embodiments, numbers are used to describe the quantity of components and attributes. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise stated, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the description and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of the present application are approximate values, in specific embodiments, the settings of such numerical values ​​are as accurate as possible within the feasible range.

Claims

1. A solar cell, characterized in that: include: A substrate having a first surface and a second surface opposite to each other, wherein the second surface has a first region and a second region adjacent to each other in a first direction; A tunneling layer and a first doping layer are sequentially arranged below the first region; a first insulating layer, disposed below the first doping layer; a second doped layer, disposed below the second region; a plurality of contact holes, each of the contact holes penetrating the first insulating layer and exposing the first doping layer; as well as A first gate line, at least a portion of the first gate line is located in the contact hole, and the first gate line is electrically connected to the first doping layer.

2. The solar cell according to claim 1, wherein The contact hole extends deep into the first doping layer.

3. The solar cell according to claim 1, wherein The cross section of the contact hole includes a circle, an ellipse or a rectangle.

4. The solar cell according to claim 1, wherein The first gate line includes a second contact portion and a plurality of first contact portions. Each first contact portion is located in a corresponding contact hole. One end of each first contact portion directly contacts the first doped layer, and the other end directly contacts the second contact portion.

5. The solar cell according to claim 4, wherein The width of each of the first contact portions is smaller than the width of the second contact portion.

6. The solar cell according to claim 5, wherein The second contact portion is located outside the contact hole.

7. The solar cell according to claim 1, wherein The system further includes a first passivation layer, which is disposed in the second region and extends to a surface of the first insulating layer away from the substrate, wherein the second doping layer is disposed on a surface of the first passivation layer away from the substrate.

8. The solar cell according to claim 7, wherein The invention further includes a second insulating layer, which is arranged between the first passivation layer, the first doping layer and the tunneling layer along the first direction, and the side of the second insulating layer away from the substrate is in contact with the first insulating layer.

9. The solar cell according to claim 1, wherein The method further includes a transparent conductive layer formed on a surface of the second doped layer away from the substrate.

10. The solar cell according to claim 9, characterized in that The device further includes a second gate line electrically connected to the transparent conductive layer located in the second area.

11. The solar cell according to claim 9, wherein The first isolation trench and the second isolation trench are arranged on both sides of the first gate line along the first direction and penetrate the transparent conductive layer corresponding to the first area.

12. The solar cell according to claim 9, wherein The transparent conductive layer is further formed on the sidewalls and bottom of the contact hole, wherein the first gate line located in the contact hole is electrically connected to the first doped layer through the transparent conductive layer located on the bottom of the contact hole.

13. A method for manufacturing a solar cell, characterized in that: include: Providing a substrate having a first surface and a second surface facing each other, wherein the second surface has a first region and a second region adjacent to each other in a first direction; forming a tunneling layer and a first doping layer in sequence below the first region; forming a first insulating layer below the first doped layer; forming a second doped layer below the second region; forming a plurality of contact holes penetrating the first insulating layer and exposing the first doping layer; as well as A first gate line is formed, wherein at least a portion of the first gate line is located in the contact hole, and the first gate line is electrically connected to the first doped layer.

14. The method for manufacturing a solar cell according to claim 13, wherein: After forming the plurality of contact holes, a transparent conductive layer is formed, wherein the transparent conductive layer covers the surface of the second doped layer away from the substrate and covers the sidewalls of the contact holes and the first doped layer exposed by the contact holes.

15. The method for manufacturing a solar cell according to claim 14, wherein: After the step of forming the transparent conductive layer, a first isolation trench and a second isolation trench are formed, wherein the first isolation trench and the second isolation trench are located on both sides of the first gate line and penetrate the transparent conductive layer.

16. The method for manufacturing a solar cell according to claim 14, wherein: A second gate line is formed, wherein the first gate line is in direct contact with the transparent conductive layer in the contact hole, and the second gate line is electrically connected to the transparent conductive layer in the second area.

Images