Tunneling oxide layer passivation contact battery and preparation method thereof

Abstract

The invention relates to the field of solar cells, particularly provides a tunneling oxide layer passivation contact cell and a preparation method thereof, and aims to solve the problem that the open-circuit voltage of the cell is difficult to increase due to higher surface recombination of the cell. In order to achieve the purpose, the tunneling oxide layer passivation contact cell comprises a silicon substrate which is provided with a light receiving surface and a backlight surface, and the light receiving surface is provided with first metal contact areas and first non-metal contact areas which are alternately distributed; a P-type doped layer, a first passivation layer, a first antireflection layer and a front metal electrode are sequentially distributed in the first metal contact region in the direction away from the silicon substrate; a second passivation layer and a second antireflection layer are sequentially distributed on the first non-metal contact region in the direction away from the silicon substrate. According to the invention, a P-type doping layer is omitted in the first non-metal contact region, and the silicon substrate is passivated by directly using the second passivation layer and the second antireflection layer, so that the surface recombination can be reduced after passivation, and the open-circuit voltage of the cell is improved.

Description

Technical Field

[0001] The present invention relates to the field of solar cells, and in particular provides a tunneling oxide layer passivation contact cell and a preparation method thereof. Background Art

[0002] With the continuous development of solar cells, tunneling oxide passivated contact cells (TOPCon cells) have gradually captured over half of the photovoltaic solar cell market, becoming the mainstream product. For TOPCon cells, the level of surface recombination directly affects the cell's open-circuit voltage; lower surface recombination results in a higher open-circuit voltage. Surface reflectivity also affects the cell's optical performance; lower reflectivity results in a higher short-circuit current.

[0003] In order to further reduce the surface recombination of the P-type doped layer in the battery, the doping concentration of the P-type doped layer is usually reduced to increase the sheet resistance. However, the lower doping concentration will increase the contact resistance between the metal electrode and the emitter, resulting in greater semiconductor contact recombination losses, reduced contact performance, and a reduced fill factor.

[0004] Reducing surface reflectivity typically relies on process and additive optimization. Secondary texturing can also modify the pyramidal morphology, further reducing reflectivity. However, these solutions are limited in their ability to reduce reflectivity. Secondary texturing increases process complexity, resulting in poor uniformity and negatively impacting the cell's appearance yield.

[0005] Accordingly, this field requires a new technical solution to solve the above problems. Summary of the Invention

[0006] The present invention aims to solve the above-mentioned technical problem, namely, to address the difficulty in increasing the open-circuit voltage of existing cells due to the high surface recombination of existing cells. To this end, the present invention provides a tunneling oxide passivation contact cell, comprising: a silicon substrate having a light-receiving surface and a light-repelling surface; the light-receiving surface being provided with alternating first metal contact regions and first non-metallic contact regions; the first metal contact regions being provided with, in a direction away from the silicon substrate, a P-type doped layer, a first passivation layer, a first anti-reflection layer, and a front metal electrode; the front metal electrode penetrating the first anti-reflection layer and the first passivation layer to form contact with the P-type doped layer; and the first non-metallic contact regions being provided with, in a direction away from the silicon substrate, a second passivation layer and a second anti-reflection layer.

[0007] In the above-mentioned specific embodiment of the tunneling oxide layer passivation contact cell, the width ratio of the first metal contact area to the first non-metal contact area is in the range of 0.4:1-1.5:1; and / or the width range of each first non-metal contact area is: 0-0.5mm.

[0008] In the above-mentioned embodiment of the cell with tunnel oxide layer passivation contact, the first metal contact region has a positive pyramid velvet structure; the first non-metallic contact region has an inverted pyramid velvet structure.

[0009] In the above-mentioned specific embodiment of the cell with tunneling oxide passivation contact, a tunneling oxide layer, a polysilicon layer, a back passivation anti-reflection layer and a back metal electrode are sequentially distributed on the backlight surface of the silicon substrate in a direction away from the silicon substrate, and the back metal electrode penetrates the back passivation anti-reflection layer to form contact with the polysilicon layer.

[0010] In the above-mentioned specific embodiment of the cell with tunneling oxide passivation contact, the second metal contact area and the second non-metal contact area are alternately distributed on the backlight surface, and the thickness of the polysilicon layer in the second metal contact area is greater than the thickness of the polysilicon layer in the second non-metal contact area.

[0011] In the above-mentioned specific embodiment of the tunnel oxide layer passivation contact cell, the thickness of the polysilicon layer in the second metal contact area is in the range of 70nm-150nm; and / or the thickness of the polysilicon layer in the second non-metallic contact area is in the range of 5-50nm.

[0012] In the above embodiment of the cell with tunneling oxide passivation contact, the width ratio of the second metal contact region to the second non-metal contact region is 0.1:1-1.5:1; and / or the width of each second non-metal contact region is 0-0.5 mm.

[0013] In the above-mentioned specific embodiment of the cell with tunneling oxide passivation contact, a third metal contact area and a third non-metallic contact area are alternately distributed on the backlight surface; the third metal contact area is sequentially distributed with a tunneling oxide layer, a polysilicon layer, a first back passivation anti-reflection layer and a back metal electrode in a direction away from the silicon substrate, and the back metal electrode penetrates the first back passivation anti-reflection layer to form contact with the polysilicon layer; the third non-metallic contact area is provided with a second back passivation anti-reflection layer in a direction away from the silicon substrate.

[0014] In the above embodiment of the cell with tunneling oxide passivation contact, the width ratio of the third metal contact region to the third non-metal contact region is 0.4:1-2:1; and / or the width of each third non-metal contact region is 0-0.5 mm.

[0015] The present invention also provides a method for preparing a tunneling oxide layer passivation contact cell, which includes the following steps: providing a first metal contact area and a first non-metal contact area alternately distributed on the light-receiving surface of a silicon substrate; forming a P-type doping material layer on the first metal contact area and the first non-metal contact area; patterning the P-type doping material layer to form a P-type doping layer on the first metal contact area; forming a passivation layer and an anti-reflection layer on the first metal contact area and the first non-metal contact area in sequence, wherein the passivation layer and the anti-reflection layer in the first metal contact area are a first passivation layer and a first anti-reflection layer, and the passivation layer and the anti-reflection layer in the first non-metal contact area are a second passivation layer and a second anti-reflection layer; and forming a front metal electrode on the first metal contact area.

[0016] When adopting the above technical solution, the present invention sets a P-type doping layer in the first metal contact area on the front side of the silicon substrate, and the P-type doping layer still maintains an appropriate doping concentration to ensure that the contact performance between the P-type doping layer and the metal electrode is not affected; since no metal electrode is set in the first non-metallic contact area, the elimination of the P-type doping layer in the first non-metallic contact area will not affect the contact performance of the battery. The second passivation layer and the second anti-reflection layer are directly used in the first non-metallic contact area to passivate the silicon substrate, and the surface recombination is reduced after passivation. The battery structure of the present invention can significantly reduce the surface recombination of the light-receiving surface, increase the open circuit voltage of the battery, and avoid the increase in recombination loss caused by reducing the doping concentration of the P-type doping layer. In addition, since the doping layer will destroy the integrity of the surface passivation layer, after removing the P-type doping layer in the first non-metallic contact area, the second passivation layer can directly contact the silicon surface, forming a denser interface, reducing the interface state density, and further improving the minority carrier lifetime. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which: Figure 1 Schematic diagram of the structure of the tunnel oxide passivation contact cell in Example 1 of the present invention; Figure 2 Schematic diagram of the structure of the tunnel oxide passivation contact cell in the second embodiment of the present invention; Figure 3 Schematic diagram of the structure of the tunnel oxide passivation contact cell in the third embodiment of the present invention; Figure 4 It is a flow chart of the method for preparing the tunneling oxide layer passivation contact cell of the present invention.

[0018] In the figure: 1. Silicon substrate, 11. P-type doped layer, 12-1. First passivation layer, 13-1. First anti-reflection layer, 14. Front metal electrode, 12-2. Second passivation layer, 13-2. Second anti-reflection layer, 21. Tunneling oxide layer, 22. Polysilicon layer, 23. Back passivation anti-reflection layer, 24. Back metal electrode, 23-1. First back passivation anti-reflection layer, 23-2. Second back passivation anti-reflection layer. DETAILED DESCRIPTION

[0019] Preferred embodiments of the present invention are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are intended only to illustrate the technical principles of the present invention and are not intended to limit the scope of protection of the present invention. Those skilled in the art may adjust these embodiments as needed to suit specific applications.

[0020] It should be noted that, in the description of the present invention, terms such as "upper," "lower," "left," "right," "inner," and "outer" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. These are used solely for ease of description and are not intended to indicate or imply that the relevant devices or components must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, ordinal numbers such as "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0021] Furthermore, it should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted" and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; and direct or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0022] Furthermore, in order to more clearly demonstrate the core technical solution of the present invention, the description of the well-known structures of solar cells is omitted in the following description. However, this omission is only for the convenience of description and does not mean that solar cells can be without these structures.

[0023] Example 1

[0024] like Figure 1As shown, the present invention proposes a tunneling oxide passivation contact cell, comprising: a silicon substrate 1 having a light-receiving surface and a light-receiving surface. A first metal contact region (denoted by A1 in the figure) and a first non-metallic contact region (denoted by A2 in the figure) are alternately arranged on the light-receiving surface, depending on whether or not they will contact a metal electrode. The silicon substrate 1 may be an N-type silicon substrate. The first metal contact region comprises, in sequence, a P-type doped layer 11, a first passivation layer 12-1, a first anti-reflection layer 13-1, and a front metal electrode 14, arranged in the direction away from the silicon substrate 1. The P-type doped layer 11 is used to form a PN junction and may be a boron-doped P-type layer formed by a boron diffusion process. The front metal electrode 14 penetrates the first anti-reflection layer 13-1 and the first passivation layer 12-1 to form a good contact with the P-type doped layer 11. The first non-metallic contact region comprises, in sequence, a second passivation layer 12-2 and a second anti-reflection layer 13-2, arranged in the direction away from the silicon substrate 1. The first passivation layer 12 - 1 and the second passivation layer 12 - 2 can be simultaneously prepared by the same process; the first anti-reflection layer 13 - 1 and the second anti-reflection layer 13 - 2 can be simultaneously prepared by the same process.

[0025] To address the problem in prior art batteries that have difficulty increasing their open-circuit voltage due to high surface recombination, this embodiment proposes a zoning solution. A P-type doped layer 11 is provided within the first metal contact region on the front surface of the silicon substrate 1. This P-type doped layer 11 maintains an appropriate doping concentration to ensure that the contact performance between the P-type doped layer 11 and the front metal electrode 14 is not affected. Since no metal electrode is provided within the first non-metallic contact region, the elimination of the P-type doped layer 11 within the first non-metallic contact region does not affect the contact performance of the battery. The silicon substrate 1 is directly passivated using a second passivation layer 12-2 and a second anti-reflection layer 13-2 within the first non-metallic contact region. After passivation, surface recombination is reduced. The battery structure of this embodiment significantly reduces surface recombination on the light-receiving surface, improves the battery's open-circuit voltage, and avoids the increased recombination losses associated with reducing the doping concentration of the P-type doped layer 11. In addition, since the doping layer will destroy the integrity of the surface passivation layer, after removing the P-type doping layer 11 of the first non-metallic contact area, the second passivation layer 12-2 can directly contact the silicon surface, forming a denser interface, reducing the interface state density (Dit), and further improving the minority carrier lifetime.

[0026] In addition, the first metal contact area shown in the figure protrudes from the first non-metal contact area. This is only used as an example. Without affecting the electrode printing, those skilled in the art can adjust the relative positions of the first metal contact area and the first non-metal contact area according to different manufacturing methods. For example, the first metal contact area can be located at the same height as the first non-metal contact area, and the first non-metal contact area can also protrude from the first metal contact area, as long as there is no P-type doped layer 11 in the first non-metal area.

[0027] Furthermore, the width ratio of the first metal contact area to the first non-metal contact area is in the range of 0.4:1-1.5:1, that is, the ratio of the width of the first metal contact area to the width of the first non-metal contact area is in the range of 0.4:1-1.5:1; and / or the width of each first non-metal contact area is in the range of 0-0.5 mm, that is, the width of the first non-metal contact area is not greater than 0.5 mm. Figure 1 As shown, the width direction is represented by the X direction in the figure.

[0028] It should be noted that the widths of the first metal contact area and the first non-metallic contact area shown in the figure are only examples and are not limitations of the present invention. Without deviating from the basic principles of the present invention, those skilled in the art can adjust the widths and width ratios of the first metal contact area and the first non-metallic contact area according to actual conditions, as long as the front metal electrode 14 is located in the first metal contact area after printing. For example, if the printing accuracy of the front metal electrode 14 is low, the width of the first metal contact area can be appropriately widened. This does not deviate from the principles of the present invention and therefore falls within the scope of protection of the present invention.

[0029] Further, if Figure 1-3 As shown, the first metal contact region has a plurality of positive pyramid velvet structures, and the first non-metal contact region has a plurality of inverted pyramid velvet structures, wherein the direction away from the silicon substrate 1 is positive and the direction pointing toward the silicon substrate 1 is inverted.

[0030] Although the inverted pyramid velvet structure has a larger specific surface area and lower reflectivity, its metal contact composite is larger than that of the positive pyramid velvet structure, and the larger the metal contact composite, the lower the open circuit voltage of the battery; since a metal grid line is provided in the first metal contact area, in order to avoid increasing the metal contact composite and causing the open circuit voltage to decrease, a positive pyramid velvet structure is provided in the first metal contact area in this embodiment; at the same time, the first metal contact area adopts a positive pyramid velvet structure, which can better adapt to the laser-assisted sintering LECO process.

[0031] Since there is no metal electrode in the first non-metallic area, setting an inverted pyramid velvet structure in the first non-metallic contact area will not improve the metal contact composite. Setting an inverted pyramid velvet structure in the first non-metallic area can increase the specific surface area and reduce the light reflectivity on the basis of reducing the surface composite of the first non-metallic area, thereby improving the optical performance of the battery, increasing light absorption, and thus increasing the short-circuit current of the battery.

[0032] It should be pointed out that the number and size of the positive pyramid velvet and the inverted pyramid velvet in the figure are only for example and are not a limitation of the present invention. Without departing from the basic principles of the present invention, those skilled in the art can adjust the number and size of the positive pyramid velvet in the first metal contact area. This does not deviate from the principles of the present invention and therefore falls within the scope of protection of the present invention.

[0033] Further, if Figure 1-2 As shown, a tunneling oxide layer 21, a polysilicon layer 22, a back passivation anti-reflection layer 23, and a back metal electrode 24 are sequentially arranged on the backlight side of the silicon substrate 1 in a direction away from the silicon substrate 1. The back metal electrode 24 penetrates the back passivation anti-reflection layer 23 and forms contact with the polysilicon layer 22. The polysilicon layer 22 is generally a phosphorus-doped N-type polysilicon layer.

[0034] Example 2

[0035] like Figure 2 As shown, based on the first embodiment, a second metal contact area (represented by B1 in the figure) and a second non-metal contact area (represented by B2 in the figure) are alternately distributed on the backlight surface according to whether they will contact the metal electrode, and the thickness of the polysilicon layer 22 in the second metal contact area is greater than the thickness of the polysilicon layer 22 in the second non-metal contact area.

[0036] The light is irradiated onto the light-receiving surface, passes through the silicon substrate 1, the tunneling oxide layer 21 and the polysilicon layer 22 in sequence, and irradiates the back passivation anti-reflection layer 23. Then, it is reflected by the back passivation anti-reflection layer 23, passes through the polysilicon layer 22 and the tunneling oxide layer 21, and finally reaches the interior of the silicon substrate 1, where it is reused by the silicon substrate 1 to generate carriers.

[0037] Since the polysilicon layer 22 on the back side has a strong parasitic absorption of light, a large portion of the long-wave light will be absorbed by the polysilicon layer 22 while passing through the polysilicon layer 22. The absorbed portion cannot be reflected by the passivation anti-reflection layer 23, so the long-wave light that can be reused by the silicon substrate 1 is reduced, and the light utilization efficiency is reduced.

[0038] In order to reduce the parasitic absorption of long-wave light by the polysilicon layer 22 and improve the utilization rate of light, the thickness of the polysilicon layer 22 in the second non-metallic contact area is reduced in this embodiment. This can reduce the parasitic absorption of long-wave light by the second non-metallic contact area, improve the utilization rate of light, and increase the short-circuit current of the battery.

[0039] Furthermore, the thickness of the polysilicon layer 22 in the second metal contact region is in a range of 70 nm to 150 nm; and / or the thickness of the polysilicon layer 22 in the second non-metal contact region is in a range of 5 nm to 50 nm.

[0040] Furthermore, the width ratio of the second metal contact region to the second non-metal contact region is 0.1:1-1.5:1; and / or the width of each second non-metal contact region is 0-0.5 mm, that is, the width of each second non-metal contact region does not exceed 0.5 mm.

[0041] It should be pointed out that, without departing from the basic principles of the present invention, those skilled in the art can adjust the width of the second metal contact area and the second non-metal contact area, as well as the thickness of the polysilicon layer 22 in the second metal contact area and the second non-metal contact area according to actual conditions.

[0042] Example 3

[0043] like Figure 3 As shown, based on Example 1, a third metal contact region (represented by C1 in the figure) and a third non-metallic contact region (represented by C2 in the figure) are alternately distributed on the backlight surface, depending on whether they will contact the metal electrode. The third metal contact region is sequentially distributed with a tunneling oxide layer 21, a polysilicon layer 22, a first backside passivation anti-reflection layer 23-1, and a backside metal electrode 24 in the direction away from the silicon substrate 1. The backside metal electrode 24 penetrates the first backside passivation anti-reflection layer 23-1 and forms contact with the polysilicon layer 22. The third non-metallic contact region is provided with a second backside passivation anti-reflection layer 23-2 in the direction away from the silicon substrate 1. The first backside passivation anti-reflection layer 23-1 and the second backside passivation anti-reflection layer 23-2 can be prepared simultaneously using the same process.

[0044] To reduce parasitic absorption of long-wavelength light by the polysilicon layer 22 and improve light utilization, this embodiment does not include a polysilicon layer in the third non-metallic contact region. This reduces parasitic absorption of long-wavelength light by the third non-metallic contact region, improves light utilization, and increases the battery's short-circuit current. Furthermore, since no polysilicon layer is provided in the third non-metallic contact region, a tunneling oxide layer is no longer required.

[0045] Furthermore, in an embodiment in which the polysilicon layer 22 in the third non-metallic contact region is removed, the width ratio of the third metal contact region to the third non-metallic contact region is 0.4:1-2:1; and / or the width of each third non-metallic contact region is 0-0.5 mm, that is, the width of each third non-metallic contact region does not exceed 0.5 mm.

[0046] A method for preparing a tunneling oxide layer passivation contact cell, the method comprising the following steps: The light-receiving surface of the silicon substrate 1 is provided with a first metal contact area and a first non-metal contact area that are alternately distributed; forming a P-type doping material layer on the first metal contact region and the first non-metal contact region; Patterning the P-type doping material layer to form a P-type doping layer 11 on the first metal contact region; forming a passivation layer and an anti-reflection layer in sequence on the first metal contact region and the first non-metal contact region, wherein the passivation layer and the anti-reflection layer in the first metal contact region are the first passivation layer 12-1 and the first anti-reflection layer 13-1, and the passivation layer and the anti-reflection layer in the first non-metal contact region are the second passivation layer 12-2 and the second anti-reflection layer 13-2; A front metal electrode 14 is formed on the first metal contact region.

[0047] Before forming the P-type doping material layer on the first metal contact region and the first non-metal contact region, the preparation method further includes the following steps: forming a positive pyramid velvet structure on the light-receiving surface and the backlight surface of the silicon substrate 1; In addition, after “patterning the P-type doping material layer to form a P-type doping layer 11 on the first metal contact region”, the following step is also included: preparing an inverted pyramid morphology in the first non-metallic contact region.

[0048] Furthermore, “patterning the P-type doping material layer to form a P-type doping layer 11 on the first metal contact area” is specifically as follows: protecting the first metal contact area with a mask, patterning the P-type doping material layer, removing the P-type doping material layer in the first non-metallic contact area, and forming a P-type doping layer 11 on the first metal contact area; “preparing an inverted pyramid morphology in the first non-metallic contact area” is specifically as follows: texturing the first non-metallic contact area again to form an inverted pyramid morphology, and then removing the mask of the first metal contact area.

[0049] Furthermore, a passivation layer and an anti-reflection layer are formed on the first metal contact region and the first non-metal contact region. Prior to this, a tunneling oxide layer 21 and a polysilicon layer 22 are first formed on the backlight surface of the silicon substrate 1 .

[0050] In the above preparation method, "preparing a tunneling oxide layer 21 and a polysilicon layer 22 on the backlight surface of the silicon substrate 1" is specifically: preparing a tunneling oxide layer 21 and a polysilicon layer 22 on the backlight surface of the silicon substrate 1, wherein the thickness of the polysilicon layer 22 in the second metal contact area is greater than the thickness of the polysilicon layer 22 in the second non-metallic contact area; and / or "preparing a tunneling oxide layer 21 and a polysilicon layer 22 on the backlight surface of the silicon substrate 1" is specifically: preparing the polysilicon layer 22 only in the third metal contact area, and not preparing the polysilicon layer 22 in the third non-metallic contact area.

[0051] There are many methods in the art to make the thickness of the polysilicon layer 22 in the second metal contact area greater than the thickness of the polysilicon layer 22 in the second non-metal contact area. For example, when the thickness of the polysilicon layer 22 in the second non-metal contact area reaches the required thickness, a silicon oxide film is deposited thereon, and the silicon oxide film is etched away later; or the thickness of the polysilicon layer 22 in the second non-metal contact area is controlled by a mask, etc. These are not the focus of the present invention, so they will not be described in detail.

[0052] Furthermore, while forming the passivation layer and the anti-reflection layer on the first metal contact region and the first non-metal contact region, a back passivation anti-reflection layer 23 is formed on the backlight side of the silicon substrate 1. The back passivation anti-reflection layers in the third metal contact region and the third non-metal contact region are respectively a first back passivation anti-reflection layer 23-1 and a second back passivation anti-reflection layer 23-2.

[0053] Furthermore, while forming the front metal electrode 14 on the first metal contact area, a back metal electrode 24 is prepared on the backlight surface of the silicon substrate 1; the front metal electrode 14 forms a good contact with the P-type doped layer 11, and the back metal electrode 24 forms a good contact with the polysilicon layer 22.

[0054] “While forming the front metal electrode 14 on the first metal contact area, preparing the back metal electrode 24 on the backlight surface of the silicon substrate 1” specifically means: preparing the front metal electrode 14 in the first metal contact area on the light-receiving surface of the silicon substrate 1; preparing the back metal electrode 24 in the second metal contact area or the third metal contact area on the backlight surface of the silicon substrate 1.

[0055] In the above preparation method, before forming the tunneling oxide layer 21 and the polysilicon layer 22 on the backlight side of the silicon substrate 1 , the backlight side of the silicon substrate 1 needs to be polished.

[0056] like Figure 4 As shown, in a possible embodiment, the preparation method includes the following steps: S1: Cleaning the silicon substrate 1 and simultaneously preparing a positive pyramid velvet surface on the light-receiving side and the backlight side; S2: forming a P-type doping material layer on the first metal contact region and the first non-metal contact region on the light-receiving surface of the silicon substrate 1; S3: Protecting the first metal contact region with a mask, patterning the P-type doping material layer, removing the P-type doping layer 11 in the first non-metallic contact region, and forming a P-type doping layer 11 on the first metal contact region; S4: texturing the first non-metallic contact area again to form an inverted pyramid morphology, and then removing the mask of the first metal contact area; S5: polishing the backlight surface of the silicon substrate 1; S6: forming a tunneling oxide layer 21 and a polysilicon layer 22 on the backlight surface of the silicon substrate 1, wherein the thickness of the polysilicon layer 22 in the second metal contact area is greater than the thickness of the polysilicon layer 22 in the second non-metal contact area; S7: forming a passivation layer and an anti-reflection layer on the light-receiving surface of the silicon substrate 1, wherein the passivation layer and the anti-reflection layer in the first metal contact area are the first passivation layer 12-1 and the first anti-reflection layer 13-1, and the passivation layer and the anti-reflection layer in the first non-metallic contact area are the second passivation layer 12-2 and the second anti-reflection layer 13-2; forming a back passivation anti-reflection layer 23 on the backlight surface of the silicon substrate 1; S8: Prepare a front metal electrode 14 in the first metal contact area on the light-receiving surface of the silicon substrate 1, so that the front metal electrode 14 forms good contact with the P-type doped layer 11; prepare a back metal electrode 24 in the second metal contact area or the third metal contact area on the backlight surface of the silicon substrate 1, and make the back metal electrode 24 form good contact with the polysilicon layer 22.

[0057] Those skilled in the art will appreciate that although some embodiments described herein include certain features included in other embodiments but not other features, combinations of features from different embodiments are intended to be within the scope of this application and to form different embodiments. For example, in the claims of this application, any of the claimed embodiments may be used in any combination.

[0058] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A tunneling oxide passivation contact cell, characterized in that: include: A silicon substrate (1), the silicon substrate (1) having a light-receiving surface and a light-receiving surface, the light-receiving surface being provided with first metal contact areas and first non-metal contact areas that are alternately distributed, The first metal contact region is sequentially distributed along a direction away from the silicon substrate (1): a P-type doped layer (11), a first passivation layer (12-1), a first anti-reflection layer (13-1), and a front metal electrode (14); the front metal electrode (14) penetrates the first anti-reflection layer (13-1) and the first passivation layer (12-1) to form contact with the P-type doped layer (11); A second passivation layer (12-2) and a second anti-reflection layer (13-2) are sequentially distributed on the first non-metallic contact area in a direction away from the silicon substrate (1).

2. The tunneling oxide passivation contact cell according to claim 1, characterized in that: The width ratio of the first metal contact area to the first non-metal contact area is in the range of 0.4:1-1.5:1; and / or The width of each of the first non-metallic contact areas is in the range of 0-0.5 mm.

3. The tunneling oxide passivation contact cell according to claim 1, characterized in that: The first metal contact region has a positive pyramid velvet structure; The first non-metallic contact region has an inverted pyramid velvet structure.

4. The tunnel oxide passivation contact cell according to any one of claims 1 to 3, characterized in that: A tunneling oxide layer (21), a polysilicon layer (22), a back passivation anti-reflection layer (23), and a back metal electrode (24) are sequentially distributed on the backlight surface of the silicon substrate (1) in a direction away from the silicon substrate (1); the back metal electrode (24) penetrates the back passivation anti-reflection layer (23) and forms contact with the polysilicon layer (22).

5. The tunneling oxide passivation contact cell according to claim 4, characterized in that: A second metal contact area and a second non-metal contact area are alternately distributed on the backlight surface, and the thickness of the polysilicon layer (22) in the second metal contact area is greater than the thickness of the polysilicon layer (22) in the second non-metal contact area.

6. The tunneling oxide passivation contact cell according to claim 5, characterized in that: The thickness of the polysilicon layer (22) in the second metal contact region is in the range of 70 nm to 150 nm; and / or The thickness of the polysilicon layer (22) in the second non-metallic contact area is in the range of 5-50 nm.

7. The tunneling oxide passivation contact cell according to claim 5, characterized in that: The width ratio of the second metal contact area to the second non-metal contact area is 0.1:1-1.5:1; and / or The width of each of the second non-metallic contact areas is 0-0.5 mm.

8. The tunnel oxide passivation contact cell according to any one of claims 1 to 3, characterized in that: The backlight surface is alternately provided with a third metal contact area and a third non-metal contact area; The third metal contact region is sequentially distributed with a tunneling oxide layer (21), a polysilicon layer (22), a first back passivation anti-reflection layer (23-1), and a back metal electrode (24) in a direction away from the silicon substrate (1); the back metal electrode (24) penetrates the first back passivation anti-reflection layer (23-1) to form contact with the polysilicon layer (22); The third non-metallic contact area is provided with a second backside passivation anti-reflection layer (23-2) in a direction away from the silicon substrate (1).

9. The tunneling oxide passivation contact cell according to claim 8, characterized in that: The width ratio of the third metal contact region to the third non-metal contact region is 0.4:1-2:1; and / or The width of each of the third non-metallic contact areas is 0-0.5 mm.

10. A method for preparing a tunnel oxide passivation contact cell, characterized in that: The preparation method comprises the following steps: A first metal contact area and a first non-metal contact area are alternately distributed on a light-receiving surface of a silicon substrate (1); a P-type doping material layer is formed on the first metal contact area and the first non-metal contact area; Patterning the P-type doping material layer to form a P-type doping layer (11) on the first metal contact area; A passivation layer and an anti-reflection layer are sequentially formed on the first metal contact area and the first non-metal contact area, wherein the passivation layer and the anti-reflection layer in the first metal contact area are a first passivation layer (12-1) and a first anti-reflection layer (13-1), and the passivation layer and the anti-reflection layer in the first non-metal contact area are a second passivation layer (12-2) and a second anti-reflection layer (13-2); A front metal electrode (14) is formed on the first metal contact area.

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