Back contact solar cell and method of manufacturing the same

Abstract

To provide a back contact type solar battery and a manufacturing method of the same.SOLUTION: A back contact type solar battery comprises: a silicon substrate having a front surface and a back surface that are opposite; a first emitter and a second emitter that are arranged on the back surface of the silicon substrate; a second separation region that surrounds the second emitter and a first separation region that surrounds the second separation region; and a second electrode in which a first part is in contact with the second emitter, and a second part is installed on the side separated from the silicon substrate of the corresponding first emitter. The first part of the second electrode is surrounded by the first separation region, or a whole of the second electrode is in contact with the second emitter, and a whole of the second electrode is surrounded by the first separation region. The back contact type solar battery avoids an electric leakage exceeding a reference value of a solar battery due to a contact of the first and second emitters by separating the first and second emitters by the first and second separation regions.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This application relates generally to the art of photovoltaics, and more particularly to back-contact solar cells and methods for fabricating back-contact solar cells. [Background technology]

[0002] Combined with passivation contact technology, all-back contact solar cells have a photoelectric conversion efficiency of over 26%, making them highly applicable.

[0003] Back-contact batteries have a problem with reverse leakage. To address this issue, a tunnel oxide layer is typically used as an etching stopper layer to prevent the formation of pyramidal suede structures on the backside of the cell during the suede process, while also removing any remaining diffusion junctions in the P region. However, this process has the drawbacks of being difficult due to a narrow process window. Furthermore, incomplete etching of the diffusion junctions can lead to significant differences in leakage between cells from different lots, resulting in reverse leakage exceeding the standard value.

[0004] Therefore, eliminating the reverse leakage current exceeding the standard value of back-contact batteries is an issue that needs to be resolved as soon as possible. Summary of the Invention [Problem to be solved by the invention]

[0005] SUMMARY OF THE INVENTION An object of the present application is to provide a back-contact solar cell that can solve the problem of reverse leakage current exceeding the standard value of a back-contact solar cell, and a method for manufacturing the back-contact solar cell. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the present application provides a back-contact solar cell comprising: a silicon substrate of a first doping type having opposing front and back surfaces; a first emitter and a second emitter arranged on the back surface of the silicon substrate; a second isolation region surrounding the second emitter and a first isolation region surrounding the second isolation region; a second electrode having a first portion in contact with the second emitter and a second portion disposed on the side of the corresponding first emitter away from the silicon substrate; wherein the first isolation region surrounds a first portion of the second electrode; or the entire second electrode contacts the second emitter and the first isolation region surrounds the entire second electrode; and wherein the first emitter is of a second doping type and the second emitter is of a first doping type.

[0007] In one embodiment of the present application, the semiconductor device further comprises an insulating layer disposed between the second electrode of the second portion and the corresponding first emitter.

[0008] In one embodiment of the present application, the entire second electrode is in contact with the second emitter, and the first isolation region surrounds the entire second electrode.

[0009] In one embodiment of the present application, the first emitter includes a diffusion layer, a tunnel oxide layer, and a polysilicon layer sequentially disposed on the back surface of the silicon substrate, the diffusion layer being of the second doping type, and the polysilicon layer being of the second doping type.

[0010] In one embodiment of the present application, the device further comprises a first passivation layer and an anti-reflection layer disposed in sequence on the front side of the silicon substrate.

[0011] In one embodiment of the present application, the first passivation layer includes a chemical passivation layer disposed on a front side of the silicon substrate and a field passivation layer disposed on a side of the chemical passivation layer away from the silicon substrate.

[0012] In one embodiment of the present application, the semiconductor device further comprises a second passivation layer disposed on the rear surface of the silicon substrate.

[0013] In order to solve the above technical problem, the present application further provides a method for manufacturing a back-contact solar cell, including the steps of: providing a silicon substrate of a first doping type having opposing front and back surfaces; forming a first emitter and a second emitter on the back surface of the silicon substrate; forming a second isolation region on the back surface of the silicon substrate, the second isolation region surrounding the second emitter and the first isolation region surrounding the second isolation region; and forming a second electrode, the first portion of which contacts the second emitter and the second portion of which is located on the side of the corresponding first emitter away from the silicon substrate, wherein the first isolation region surrounds a first portion of the second electrode, or the entire second electrode contacts the second emitter and the first isolation region surrounds the entire second electrode, the first emitter is of a second doping type, and the second emitter is of a first doping type.

[0014] In one embodiment of the present application, the first emitter includes a diffusion layer, a tunnel oxide layer, and a polysilicon layer sequentially disposed on the back surface of the silicon substrate, and the diffusion layer and the polysilicon layer are of the second doping type.

[0015] In one embodiment of the present application, a first passivation layer and an anti-reflection layer are sequentially formed on the front surface of the silicon substrate.

[0016] In one embodiment of the present application, the first passivation layer includes a chemical passivation layer disposed on a front side of the silicon substrate and a field passivation layer disposed on a side of the chemical passivation layer away from the silicon substrate. [Effects of the Invention]

[0017] The back-contact solar cell of the present application separates the first emitter and the second emitter by a first isolation region and a second isolation region, thereby avoiding leakage current exceeding the standard value of the solar cell due to contact between the first emitter and the second emitter.

[0018] To make the above objects, features, and advantages of the present application more clearly and comprehensibly, specific embodiments of the present application are described in detail below with reference to the accompanying drawings. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a schematic bottom view of a back-contact solar cell according to one embodiment of the present application. [Figure 2] FIG. 2 is a schematic cross-sectional view showing a cross section along the line AA in FIG. [Figure 3] FIG. 2 is a schematic cross-sectional view showing a cross section along the line BB in FIG. [Figure 4] FIG. 2 is a schematic bottom view of a back-contact solar cell according to another embodiment of the present application. [Figure 5] 1 is an exemplary flowchart of a method for manufacturing a back contact solar cell in accordance with one embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0020] To make the above objects, features, and advantages of the present application clearer and more easily understandable, specific embodiments of the present application will be described in detail below in conjunction with the accompanying drawings.

[0021] In the following description, numerous specific details are set forth to facilitate a thorough understanding of the present application; however, the present application may be practiced in other ways than those described, and therefore the present application is not limited to the specific examples disclosed below.

[0022] As set forth in this application and the claims, unless the context clearly indicates otherwise, terms such as "a," "one," "one," "a kind," and / or "the" do not specifically refer to the singular but may also include the plural. Generally, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, and do not constitute an exclusive list of these steps and elements; a method or apparatus may include other steps or elements.

[0023] It should also be noted that the use of terms such as "first" and "second" to define components is merely to facilitate distinguishing between corresponding components, and that unless otherwise stated, the terms do not have any special meaning and therefore should not be understood as limiting the scope of protection of the present application. Furthermore, although the terms used in the present application are selected from well-known terms, some terms described in the specification of the present application have been selected by the applicant at his / her own discretion, and their detailed meanings will be explained in the relevant parts of the description of this specification. It is also required to understand the present application not only by the actual terms used but also by the meanings contained in each term.

[0024] In this application, the operations performed by the system according to the embodiment of this application are described in flowcharts. It should be understood that the above or following operations are not necessarily performed in exact order. Conversely, various steps may be processed in reverse order or simultaneously. Meanwhile, other operations may be added to these processes, or one or more operations of these steps may be removed from these processes.

[0025] Next, the back-contact solar cell of the present application will be described using specific examples.

[0026] FIG. 1 is a schematic bottom view of a back-contact solar cell according to one embodiment of the present application, and FIG. 2 is a schematic cross-sectional view taken along line AA in FIG. 1 . As shown in FIGS. 1 and 2 , the back-contact solar cell 100 includes a silicon substrate 110, a first emitter 120, a first isolation region 130, a second isolation region 140, and a second emitter 150. Due to limitations in the drawing space, FIG. 2 only shows a portion of the cross-sectional view taken along line AA. As can be seen from FIG. 2 , the surfaces of the first isolation region 130 and the second isolation region 140 away from the silicon substrate 110 in the thickness direction D2 are covered with other material layers, so the first isolation region 130 and the second isolation region 140 are not actually visible in the bottom view of FIG. 1 . However, for convenience of explanation, the locations of the first isolation region 130 and the second isolation region 140 are schematically shown in FIG. 1 .

[0027] 2, the silicon substrate 110 has a front surface 111 and a back surface 112 that face each other in the thickness direction D2, and the silicon substrate 110 is of a first doping type. Here, the first doping type may be P-type, i.e., the silicon substrate 110 may be a P-type silicon substrate, or N-type, i.e., the silicon substrate 110 may be an N-type silicon substrate. The present application does not limit the specific doping elements that form the P-type silicon substrate and the N-type silicon substrate.

[0028] 2, the first emitter 120, the first isolation region 130, the second isolation region 140, and the second emitter 150 are provided along a first direction D1 on the back surface 112 of the silicon substrate 110, with the first emitter 120 being of a second doping type and the second emitter 150 being of a first doping type. In FIG. 2, the right side of the first isolation region 130 is in contact with the first emitter 120, the left side of the first isolation region 130 is in contact with the right side of the second isolation region 140, and the left side of the second isolation region 140 is in contact with the second emitter 150. It should be understood that the above description of the positional relationship between the first emitter 120, the first isolation region 130, the second isolation region 140, and the second emitter 150 applies to the second emitter 150 and the first emitter 120, the first isolation region 130, and the second isolation region 140 located to the right of it. The above description may be referred to for the positional relationship between the second emitter 150 and the first emitter 120, the first isolation region 130, and the second isolation region 140 located to the left of it, and therefore a description thereof will be omitted here.

[0029] Note that the positional relationship between the first emitter 120, the first isolation region 130, the second isolation region 140, and the second emitter 150 is not limited to the embodiment of Fig. 1. For example, in some other embodiments, the first isolation region 130 and the second isolation region 140 are arranged between the first emitter 120 and the second emitter 150 along the first direction D1 so as not to contact each other, or the first isolation region 130 and the second isolation region 140 are in contact with each other, but the first isolation region 130 is not in contact with the first emitter 120, and the second isolation region 140 is not in contact with the second emitter 150.

[0030] As shown in FIGS. 1 and 2 , in one embodiment, the back-contact solar cell 100 further includes a first electrode 161 and a second electrode 162. The first electrode 161 is in contact with the first emitter 120, thereby electrically connected to the first emitter 120. Similarly, the second electrode 162 is in contact with the second emitter 150, thereby electrically connected to the second emitter 150. Here, the second electrode 162 and the second emitter 150 are electrically connected in two cases: (1) when a portion of the second electrode 162 is in contact with the second emitter 150, and (2) when the entire second electrode 162 is in contact with the second emitter 150. These two cases will be described below.

[0031] Case 1: A portion of the second electrode is in contact with the second emitter.

[0032] As explained with reference to Figure 1, Figure 1 shows the back surface of the back contact solar cell 100. Unlike the appearance of the first electrode 161 and the second electrode 162 shown in Figure 2, the first electrode 161 and the second electrode 162 are shown as line segments in Figure 1. It can be understood that this is due to the angle of the drawing.

[0033] 1, the first isolation region 130 surrounds the second isolation region 140. In combination with FIG. 2, the second isolation region 140 surrounds the second emitter 150, and the first portion 162a of the second electrode 162 is surrounded by the first isolation region 130. Referring to the schematic cross-sectional view of line BB in FIG. 1 shown in FIG. 3, the second portion 162b of the second electrode 162 is provided on the side of the corresponding first emitter 120 away from the silicon substrate 110. In other words, in FIG. 1, the first isolation region 130 is represented as a rectangular frame, the second electrode located within the rectangular frame is the first portion 162a of the second electrode, and the second electrode located outside the rectangular frame is the second portion 162b of the second electrode.

[0034] As shown in FIGS. 1 and 2, the first emitter 120 and the second emitter 150 are not visible in FIG. 1 because their surfaces away from the silicon substrate 110 are covered with another material layer. To more clearly understand the layout of the second electrode in Case 1, the first emitter and the second emitter will now be described based on FIG. 1. In FIG. 1, the second emitter is located below the first portion 162a of the second electrode, and the first emitter (as shown in FIG. 3) is distributed below the second portion 162b of the second electrode. An insulating layer (not shown) is provided between the second portion 162b of the second electrode and the first emitter located below it. Therefore, the second electrode is not electrically connected to the first emitter. The term "below" above refers to facing into the plane of the paper.

[0035] 2 and 3, back-contact solar cell 100 further includes second passivation layer 170 and third passivation layer 180 provided in this order along thickness direction D2 on the back surface of silicon substrate 110. Second portion 162b of the second electrode is provided on a surface of third passivation layer 180 that is remote from third passivation layer 180 in thickness direction D2. In some embodiments, the back-contact solar cell 100 further includes an insulating layer (not shown) disposed between the second electrode second portion 162b and the third passivation layer 180, as shown in Figure 3, or the second passivation layer 170 and the third passivation layer 180 where the second electrode second portion 162b is located in Figure 3 are removed using a method such as etching to expose the first emitter 120, and an insulating layer is disposed between the second electrode second portion 162b and the corresponding first emitter 120. In some embodiments, if the back-contact solar cell 100 does not include the second passivation layer 170 and the third passivation layer 180, the insulating layer is disposed between the second electrode second portion 162b and the corresponding first emitter 120. Returning to FIG. 1, the first isolation region 130 surrounds the first portion 162a of the second electrode, and an insulating layer is provided between the second portion 162b of the second electrode and the corresponding first emitter 120, so that the second electrode 162 is not electrically connected to the first emitter 120.

[0036] In one embodiment, the second passivation layer and the third passivation layer are a composite of one or more of silicon nitride, aluminum oxide, titanium oxide, silicon oxide, and silicon oxynitride.

[0037] 1 and 2, the second emitter 150 is surrounded by the second isolation region 140, and the second isolation region 140 is surrounded by the first isolation region 130. In this way, the first emitter 120 and the second emitter 150 are separated by the first isolation region 130 and the second isolation region 140, so that leakage of electricity from the cell due to contact between the first emitter 120 and the second emitter 150 can be avoided.

[0038] Case 2: The entire second electrode is in contact with the second emitter.

[0039] Referring to the schematic bottom view of a back-contact solar cell according to another embodiment of the present application shown in Figure 4 and Figure 2, the schematic cross-sectional view shown in Figure 2 may also represent a schematic cross-sectional view taken along line CC in Figure 4. Different from Figure 1, in Figure 4, the second electrode 162 is entirely in contact with the second emitter 150, and the second isolation region 140 surrounds the second electrode 162 entirely, and the first isolation region 130 surrounds the second isolation region 140. It can be seen from Figure 4 that the first isolation region 130 surrounds the second electrode 162 entirely.

[0040] Furthermore, similar to case 1, the first emitter 120 and the second emitter 150 are separated by the first isolation region 130 and the second isolation region 140 to avoid cell leakage due to contact between the first emitter 120 and the second emitter.

[0041] In the above embodiment, the second emitter has been described, and next, the first emitter of the present application will be described.

[0042] As shown in FIG. 2 , the first emitter 120 includes a diffusion layer 121, a tunnel oxide layer 122, and a polysilicon layer 123. The diffusion layer 121, the tunnel oxide layer 122, and the polysilicon layer 123 are sequentially disposed on the back surface of the silicon substrate 110 in a thickness direction D2, where the diffusion layer 121 and the polysilicon layer 123 are all of a second doping type. In one embodiment, the tunnel oxide layer 122 has a thickness of 1 to 20 nm, and the polysilicon layer 123 has a thickness of 20 to 1000 nm. The tunnel oxide layer 122 may be implemented as silicon dioxide. The tunnel oxide layer 122 and the polysilicon layer 123 can achieve selective carrier collection, i.e., majority carriers easily pass through the tunnel oxide layer 122, while minority carriers have a hard time passing through the tunnel oxide layer 122.

[0043] In order to more clearly understand the technical effect of isolating the first emitter and the second emitter by the first isolation region and the second isolation region in the above-mentioned embodiment, the first isolation region and the second isolation region of the present application will now be further described.

[0044] As shown in FIG. 2 , a first isolation region 130 is provided between the first emitter 120 and the second isolation region 140 along a first direction D1. The first isolation region 130 of the present application may be implemented as a silicon substrate located between the first emitter 120 and the second isolation region 140, or as another material, such as a second passivation layer, located between the first emitter 120 and the second isolation region 140. In other words, the first isolation region 130 located between the first emitter 120 and the second isolation region 140 along the first direction D1 has the technical effect of isolating the first emitter 120 and the second emitter 150. In some embodiments, the first isolation region 130 is of a first doping type, and as shown in FIG. 2 , the first isolation region 130 may have a pyramidal suede appearance on a surface adjacent to the silicon substrate 110 along the thickness direction D2.

[0045] 2, the entire second isolation region 140 is of the second doping type. In this case, the second isolation region 140 may be the diffusion layer 121 remaining in the P region. In some other embodiments, the doping type of the second isolation region 140 may be such that a portion of the second isolation region is of the first doping type and another portion of the second isolation region is of the second doping type, and the "part" and "another portion" may constitute the entire second isolation region, or may not constitute the entire second isolation region, or the entire second isolation region may be of the first doping type.

[0046] To more clearly understand the first and second isolation regions in the back contact solar cell of the present application, an example is provided here to illustrate the process of forming the first and second isolation regions.

[0047] 2, the tunnel oxide layer 122 and the polysilicon layer 123 cover part of the back surface of the silicon substrate 110. The tunnel oxide layer 122 and the polysilicon layer 123 that partially cover the back surface of the silicon substrate 110 are formed as follows: After forming the tunnel oxide layer 122 on the back surface of the silicon substrate 110 so as to cover the entire back surface, a polysilicon layer 123 that covers the tunnel oxide layer 122 is formed on the surface of the tunnel oxide layer 122. Then, unnecessary portions of the tunnel oxide layer 122 and the polysilicon layer 123 are removed by etching or the like so as to leave the tunnel oxide layer 122 and the polysilicon layer 123 in the first emitter 120 portion. When the polysilicon layer located in the P region is retained, the entire second isolation region 140 is of the second doping type, when a portion of the polysilicon layer in the P region is retained, a portion of the second isolation region 140 is of the first doping type and the other portion is of the second doping type, and when the entire polysilicon layer in the P region is removed, the entire second isolation region 140 is of the first doping type. Note that the above-described embodiment is merely one example of forming the first isolation region and the second isolation region, and the method of forming the first isolation region and the second isolation region of the present application is not limited to the above example.

[0048] 2, the surface of the first isolation region 130 closest to the silicon substrate 110 has a pyramidal suede texture. The pyramidal suede texture of the first isolation region 130 and the pyramidal suede texture on the front surface of the silicon substrate 110 are formed in the same suede process step, and the separation process steps for forming the first isolation region 130 and the second isolation region 140 may be merged with the suede process step to simplify the process. In some other embodiments, the surface of the second isolation region 140 away from the silicon substrate 110 in the thickness direction D2 is flattened. Here, this flattening may be achieved by chemical mechanical polishing (CMP).

[0049] In one embodiment, as shown in FIG. 2 , a first passivation layer 190 and an anti-reflective layer 210 are sequentially formed on the front surface 111 of the silicon substrate 110 in a thickness direction D2. The first passivation layer 190 and the anti-reflective layer 210 are formed by chemical vapor deposition (CVD) and / or physical vapor deposition (PVD). In some embodiments, the first passivation layer 190 includes a chemical passivation layer and a field passivation layer, and the first passivation layer 190 is formed by first forming the chemical passivation layer on the front surface 111 of the silicon substrate 110, and then forming the field passivation layer on a surface of the chemical passivation layer away from the silicon substrate 110. In some embodiments, the front surface 111 of the silicon substrate 110, and the first passivation layer 190 and the anti-reflective layer 210 disposed on the front surface 111 have a pyramidal suede appearance. When the solar cell is in operation, sunlight enters the silicon substrate 110 from the front side of the silicon substrate 110, and the pyramid suede traps the light to reduce surface reflection, thereby improving the light utilization rate of the solar cell.

[0050] In the above-described embodiment of the present application, the first emitter and the second emitter are separated by the first isolation region and the second isolation region, thereby preventing leakage current exceeding the standard value of the solar cell due to contact between the first emitter and the second emitter.

[0051] Another aspect of the present application further provides a method for fabricating a back-contact solar cell, which will be described in the examples below.

[0052] 5 is an exemplary flowchart of a method for manufacturing a back-contact solar cell according to an embodiment of the present application. As shown in FIG. 5, the manufacturing method of this embodiment includes: Step S310: providing a silicon substrate of a first doping type having opposing front and back surfaces; Step S320: forming a first emitter of a second doping type, a first isolation region, a second isolation region, and a second emitter of a first doping type on the back surface of the silicon substrate; Including, A second isolation region is surrounded by the first isolation region, and a second emitter is surrounded by the second isolation region.

[0053] The above-mentioned steps S310 and S320 will now be described in detail.

[0054] 2, in step S310, a silicon substrate 110 is provided, which has a front surface 111 and a back surface 112 facing each other in a thickness direction D2, where the silicon substrate 110 is of a first doping type.

[0055] In step S320, a first emitter 120 of a second doping type, a first isolation region 130, a second isolation region 140, and a second emitter 150 of a first doping type are formed on the back surface 112 of the silicon substrate 110. As shown in FIG. 1 , the first isolation region 130 surrounds the second isolation region 140, and the second isolation region 140 surrounds the first emitter 120. As a result, the first emitter 120 and the second emitter 150 are separated by the first isolation region 130 and the second isolation region 140, and contact between the first emitter 120 and the second emitter 150 is avoided.

[0056] 1 and 2, in one embodiment, a first electrode 161 is formed in contact with the first emitter 120, and a second electrode 162 is formed in contact with the second emitter 150. This allows electrical connection between the first electrode 161 and the first emitter 120, and electrical connection between the second electrode 162 and the second emitter 150 to be achieved.

[0057] In one embodiment, the first portion 162a of the second electrode contacts the second emitter 150, the second portion 162b of the second electrode is located on the side of the corresponding first emitter away from the silicon substrate 110, an insulating layer (not shown) is located between the second portion 162b of the second electrode and the corresponding first emitter, and the first isolation region 130 surrounds the first portion 162a of the second electrode, as shown in FIG. 1.

[0058] In another embodiment, referring to FIG. 4, unlike FIG. 2, the entire second electrode 162 contacts the second emitter 150, and the first isolation region 130 surrounds the entire second electrode 162.

[0059] 2, in one embodiment, the first emitter 120 includes a diffusion layer 121, a tunnel oxide layer 122, and a polysilicon layer 123. As shown in FIG. 2, the diffusion layer 121 is disposed on the back surface of the silicon substrate 110, the tunnel oxide layer 122 is disposed on the surface of the diffusion layer 121 away from the silicon substrate 110 in the thickness direction D2, and the polysilicon layer 123 is disposed on the surface of the tunnel oxide layer 122 away from the silicon substrate 110 in the thickness direction D2. The tunnel oxide layer 122 and the polysilicon layer 123 can realize selective collection of carriers, i.e., majority carriers easily pass through the tunnel oxide layer 122, while minority carriers have difficulty passing through the tunnel oxide layer 122. Here, the diffusion layer 121 and the polysilicon layer 123 are both of the second doping type.

[0060] 2, a first passivation layer 190 and an anti-reflective layer 210 are sequentially formed on the front surface of the silicon substrate 110 in the thickness direction D2. The first passivation layer 190 and the anti-reflective layer 210 can be formed by chemical vapor deposition (CVD) and / or physical vapor deposition (PVD). In some embodiments, the first passivation layer 190 includes a chemical passivation layer and a field passivation layer, and the first passivation layer 190 can be formed by first forming the chemical passivation layer on the front surface of the silicon substrate 110, and then forming the field passivation layer on the side of the chemical passivation layer away from the silicon substrate 110.

[0061] Continuing with reference to FIG. 2 , in one embodiment, the first isolation region 130 has a pyramidal suede appearance. The pyramidal suede appearance may be formed by etching the surface of the first isolation region 130 away from the silicon substrate 110 using an alkaline solution. In one embodiment, the pyramidal suede of the first isolation region 130 is formed in the same suede process step as the pyramidal suede on the front surface of the silicon substrate 110, thereby simplifying the process. In other embodiments, the surface of the second isolation region 140 away from the silicon substrate 110 in the thickness direction D2 is flat. This may be planarized by chemical mechanical polishing (CMP).

[0062] In the above-described embodiment of the present application, the first emitter and the second emitter are separated by the first isolation region and the second isolation region, thereby preventing leakage current exceeding the standard value of the solar cell due to contact between the first emitter and the second emitter.

[0063] Although the basic concepts have been described above, it will be apparent to those skilled in the art that the above disclosure is merely illustrative and not limiting of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and amendments to the present application. Such modifications, improvements, and amendments are proposed herein and therefore fall within the spirit and scope of the exemplary embodiments of the present application.

[0064] At the same time, the present application uses specific terms to describe embodiments of the present application. For example, "one embodiment," "one embodiment," and / or "some embodiments" refer to features, configurations, or characteristics associated with at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment," "one embodiment," or "one alternative embodiment" mentioned more than once in different places in this specification do not necessarily refer to the same embodiment. Furthermore, some features, configurations, or characteristics in one or more embodiments of the present application may be combined as appropriate.

[0065] In some examples, numbers are used to describe the number of components or attributes, but it should be understood that the numbers describing such examples are, in some instances, modified using the modifiers "about," "approximately," or "approximately." Unless otherwise specified, "about," "approximately," or "approximately" means that the numerical value can vary by ±20%. Accordingly, in some examples, the numerical parameters used in the specification and claims are approximations, and these approximations may vary depending on the characteristics required for a particular example. In some examples, the numerical parameters should be calculated using a given number of significant digits and common digit preservation techniques. In some examples, the numerical fields and parameters used to determine the breadth of their ranges are approximations; however, in certain examples, such numerical values ​​are set as precisely as possible within the ranges possible. [Explanation of symbols]

[0066] 110 Silicon substrate 111 Front 112 Back side 120 First Emitter 121 Diffusion Layer 122 Tunnel oxide layer 123 Polysilicon layer 130 first separation region 140 Second Separation Region 150 Second Emitter 161 First electrode 162 Second electrode 162a First Part 162b Second part 170 Second Passivation Layer 180 Third Passivation Layer 190 First Passivation Layer 210 Anti-reflection layer

Claims

1. A back-contact solar cell, comprising: a first doping type silicon substrate having opposing front and back surfaces; a first emitter including a diffusion layer, a tunnel oxide layer, and a polysilicon layer disposed in sequence on the back surface of the silicon substrate; a second emitter located in the silicon substrate, the second emitter being in a P region and the tunnel oxide layer being discontinuous in the P region; a second isolation region surrounding the second emitter, the second isolation region being the diffusion layer remaining in the P region; and a first isolation region surrounding the second isolation region and in direct contact with a back surface of the silicon substrate; a second electrode having a first portion in contact with the second emitter and a second portion disposed on a side of the first emitter away from the silicon substrate; a second passivation layer disposed on a surface of the first emitter, the first isolation region, the second isolation region, and the second emitter that is remote from the silicon substrate; a first portion of the second electrode is surrounded by the first isolation region; the first emitter is N-type and the second emitter is P-type; the first isolation region and the second isolation region separate the first emitter and the second emitter; A back-contact solar cell, wherein the material of the first isolation region is the same as the material of the second passivation layer.

2. 10. The back contact solar cell of claim 1, further comprising an insulating layer disposed between said second electrode and said first emitter of said second portion.

3. 10. The back-contact solar cell of claim 1, further comprising a first passivation layer and an anti-reflection layer disposed sequentially on the front surface of the silicon substrate.

4. the first passivation layer comprises a chemical passivation layer disposed on the front side of the silicon substrate; 4. The back contact solar cell of claim 3, further comprising a field passivation layer disposed on a surface of said chemical passivation layer remote from said silicon substrate.

5. 1. A method for manufacturing a back contact solar cell, comprising: providing a silicon substrate of a first doping type having opposing front and back surfaces; forming a first emitter on a rear surface of the silicon substrate, the first emitter including a diffusion layer, a tunnel oxide layer, and a polysilicon layer sequentially disposed on the rear surface of the silicon substrate; forming a second emitter in the silicon substrate, the second emitter being in a P region and the tunnel oxide layer being discontinuous in the P region; forming a second isolation region on the back surface of the silicon substrate, the second isolation region surrounding the second emitter, the second isolation region being the remaining diffusion layer in the P region, and a first isolation region surrounding the second isolation region and in direct contact with the back surface of the silicon substrate; forming a second electrode, the first portion of which contacts the second emitter and the second portion of which is located on a side of the corresponding first emitter away from the silicon substrate; the first portion of the second electrode is surrounded by the first isolation region; the first emitter is N-type; the second emitter is P-type; the back-contact solar cell further comprises a second passivation layer formed on surfaces of the first emitter, the first isolation region, the second isolation region, and the second emitter that are remote from the silicon substrate; the first isolation region and the second isolation region separate the first emitter and the second emitter; 2. A method for manufacturing a back-contact solar cell, wherein the material of the first isolation region is the same as the material of the second passivation layer.

6. 6. The method for fabricating a back-contact solar cell according to claim 5, further comprising sequentially forming a first passivation layer and an anti-reflection layer on the front surface of the silicon substrate.

7. The first passivation layer comprises: a chemical passivation layer disposed on the front side of the silicon substrate; 7. The method of claim 6, further comprising: a field passivation layer disposed on a surface of said chemical passivation layer remote from said silicon substrate.

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