A preparation method of a single-sided texturing monocrystalline silicon wafer and a TOPCon cell wafer

Abstract

The application relates to the technical field of solar cells, and particularly discloses a preparation method of a single-side-textured monocrystalline silicon wafer and a TOPCon cell wafer. The preparation method of the single-side-textured monocrystalline silicon wafer comprises the following process steps: a. liquid sodium silicate is coated on a non-textured surface of a monocrystalline silicon wafer and dried to obtain a monocrystalline silicon wafer coated with a sodium silicate layer; b. the textured surface of the monocrystalline silicon wafer coated with the sodium silicate layer is subjected to texturing, and then the sodium silicate layer is removed through acid pickling to obtain a single-side-textured monocrystalline silicon wafer. The preparation method of the TOPCon cell wafer is as follows: the single-side-textured monocrystalline silicon wafer is sequentially subjected to diffusion, BSG / PSG removal, preparation of a tunneling oxide layer, polycrystalline silicon deposition + phosphorus diffusion / in-situ doping, cleaning, front-side aluminum oxide deposition, front-side silicon nitride deposition, back-side silicon nitride deposition, printing + sintering treatment, and finally the TOPCon cell wafer is obtained. The preparation method of the single-side-textured monocrystalline silicon wafer has the advantages of low cost, easy operation and high electric conversion efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of solar cells, and particularly discloses a method for preparing a single-sided textured monocrystalline silicon wafer and a TOPCon solar cell. Background Art

[0002] In the production process of monocrystalline silicon solar cells, trough-type texturing equipment is usually used. In this way, pyramid structures are produced on both sides of the silicon wafer. However, the pyramid structure on the front side (textured side) of the silicon wafer is intended to improve light absorption, while the textured structure on the back side (non-textured side) of the silicon wafer seriously affects the secondary reflection of light, reducing light utilization, and thus affecting the efficiency of the cell. In order to improve the reflectivity of light inside the silicon wafer, the pyramid on the back side needs to be removed through a polishing process. Currently, the thinning of silicon wafers has become a major trend. Polishing the back surface after texturing directly reduces the thickness of the silicon wafer, which is not conducive to improving cell efficiency. The single-sided texturing technology can eliminate the process of polishing the back side of the silicon wafer, and can produce solar cells with high cell efficiency using thinner silicon wafers.

[0003] Existing single-sided texturing processes include the mask method and the stacking method. The mask method includes silicon nitride masks and silicon oxide masks. Silicon nitride masks require vapor deposition to be prepared on the surface of silicon wafers, which has high requirements for equipment and process conditions and is complex. The glue mask is mainly composed of silicon oxide, and it needs to add additives, lignan fiber, gum arabic and other substances to prepare the glue, which is complicated. The stacking method involves stacking silicon wafers to form a tightly adsorbed stacked structure and then performing texturing to obtain a single-sided texturized silicon wafer. The stacking method is cumbersome and requires the silicon wafers to be stacked and then disassembled. The surface of the silicon wafer that has not formed a textured surface needs to be post-processed, which is cumbersome and complex. Summary of the Invention

[0004] In response to the above-mentioned defects of the existing method for preparing single-sided texturized monocrystalline silicon wafers, the present invention provides a method for preparing single-sided texturized monocrystalline silicon wafers and TOPCon solar cells. The method for preparing single-sided texturized monocrystalline silicon wafers has low cost, is easy to operate, has low equipment requirements and high electrical conversion efficiency.

[0005] To achieve the above-mentioned purpose, the embodiment of the present invention adopts the following technical solutions:

[0006] A method for preparing a single-sided textured single-crystal silicon wafer comprises the following steps:

[0007] a. coating liquid sodium silicate on the non-textured surface of a single crystal silicon wafer and drying the wafer to obtain a single crystal silicon wafer coated with a sodium silicate layer;

[0008] b. Texturing the textured surface of the single-crystal silicon wafer coated with the sodium silicate layer, and then removing the sodium silicate layer by pickling to obtain a single-side textured single-crystal silicon wafer.

[0009] Preferably, the texturing method is a conventional texturing method for single crystal silicon wafers, and the chemical solution used for texturing is a NaOH / KOH solution with a volume fraction of 0.2% to 1.5%.

[0010] Preferably, in step a, the modulus n of the liquid sodium silicate is ≥3.

[0011] Preferably, in step a, the coating method is one of spin coating, spray coating or brush coating.

[0012] Preferably, the spin coating method has a rotation speed of 10-180 r / s and a glue drop amount of 0.2 ml-5 ml.

[0013] Preferably, in the method for preparing the single-sided textured single-crystal silicon wafer, the thickness of the sodium silicate layer is 5 μm-150 μm.

[0014] Compared with the prior art, the sodium silicate layer prepared by the present invention uses sodium silicate as raw material, which is simple to obtain and has low cost. The sodium silicate layer only requires one component, sodium silicate, and has good bonding strength without adding any additives. Since sodium silicate is the reaction product of sodium hydroxide and silicon, the sodium silicate layer will no longer undergo any chemical reaction with the texturing solution, and has a good protective effect on the silicon wafer. The coatings such as silicon nitride and silicon oxide used in the prior art will react chemically with sodium hydroxide / potassium hydroxide. During the texturing process, when the silicon nitride or silicon oxide is deposited / coated unevenly, the silicon wafer will be locally corroded, and there is a risk of the protective surface being textured. That is, the present application selects a sodium silicate layer as a mask to prepare a single-sided texturing monocrystalline silicon wafer. Compared with other mask components, it not only has the advantages of easy availability of raw materials, low cost and simple coating operation, but also simplifies the process of using it to prepare solar cells. At the same time, the sodium silicate layer mask process combined with the cell preparation process can significantly improve the cell efficiency of the prepared cell.

[0015] Preferably, in the method for preparing the single-sided textured single-crystal silicon wafer, the drying temperature in step a is 70-130° C., and the drying time is 60-1800 s.

[0016] Preferably, in the preparation method of the single-sided texturized single-crystalline silicon wafer, the pickling method in step b is: immersing the single-crystalline silicon wafer coated with a sodium silicate layer in a pickling solution; the concentration of HCl in the pickling solution is 0.28mol / L-0.63mol / L, and the concentration of HF is 0.58mol / L-1.37mol / L.

[0017] Single-sided texturing ensures secondary reflection of light from the back surface of the cell, enhancing light absorption and, consequently, short-circuit current. Silicon wafers produced with single-sided texturing require no polishing and are thicker than wafers produced with double-sided texturing. This further improves light absorption and short-circuit current; thicker wafers also reduce fragmentation during the production process.

[0018] The present invention also provides a method for preparing a TOPCon cell, comprising the following steps:

[0019] The single-sided textured single-crystalline silicon wafer is sequentially subjected to diffusion, BSG / PSG removal, tunnel oxide layer preparation, polysilicon deposition + phosphorus diffusion / in-situ doping, cleaning, front-side aluminum oxide deposition, front-side silicon nitride deposition, back-side silicon nitride deposition, printing + sintering treatment to obtain the TOPCon cell;

[0020] The diffusion method comprises: performing boron diffusion or phosphorus diffusion on the single-side textured single-crystal silicon wafer in a high-temperature diffusion furnace to form a PN junction on the surface of the single-crystal silicon wafer; wherein, when the single-crystal silicon wafer is an N-type substrate, boron diffusion is performed; when the single-crystal silicon wafer is a P-type substrate, phosphorus diffusion is performed;

[0021] The method for removing BSG / PSG is as follows: using HF with a mass fraction of 3% to 49% to etch other surfaces of the diffused single crystal silicon wafer outside the PN junction, wherein the sheet resistance of the diffused single crystal silicon wafer is in the range of 60 to 200 ohms / square meter;

[0022] The method for preparing the tunnel oxide layer comprises: using a PECVD device, an LPCVD device or a PVD device to deposit a tunnel oxide layer on the surface of the single crystal silicon wafer, wherein the thickness of the tunnel oxide layer is 0.3-2.6 nm;

[0023] The polysilicon deposition + phosphorus diffusion / in-situ doping method comprises: sequentially performing polysilicon deposition and phosphorus diffusion / in-situ doping on the single-crystalline silicon wafer; wherein the polysilicon deposition method comprises: using a PECVD device, an LPCVD device, or a PVD device to prepare a polysilicon deposition layer on the surface of the single-crystalline silicon wafer, wherein the thickness of the polysilicon deposition layer is 80-160 nm; and the phosphorus diffusion / in-situ doping method comprises: using a PECVD device or a PVD device to perform in-situ doping on the polysilicon deposition layer, or using an LPCVD device to perform phosphorus diffusion on the polysilicon deposition layer.

[0024] The cleaning method comprises: placing the single crystal silicon wafer in an acid solution for cleaning, wherein the concentration of HCl in the acid solution is 0.28 mol / L-0.86 mol / L, and the concentration of HF is 0.58 mol / L-1.73 mol / L;

[0025] The method for depositing aluminum oxide on the textured surface is as follows: using a plate-type ALD or a tube-type ALD device to deposit an aluminum oxide film on the textured surface of the single crystal silicon wafer, wherein the thickness of the aluminum oxide film is 2-10 nm;

[0026] The method for depositing silicon nitride on the textured surface is as follows: using a plate-type PECVD or tube-type PECVD device to deposit a silicon nitride film on the textured surface of the single crystal silicon wafer, wherein the thickness of the silicon nitride film is 60-100 nm;

[0027] The method for depositing silicon nitride on the non-textured surface is as follows: using a plate-type PECVD or tube-type PECVD device to deposit a silicon nitride film with a passivation effect on the non-textured surface of the single crystal silicon wafer, wherein the thickness of the silicon nitride film is 50-95 nm;

[0028] The printing + sintering treatment method is: silver paste is printed on the non-textured surface of the single crystal silicon wafer by screen printing, and silver paste or aluminum paste is printed on the texturized surface of the single crystal silicon wafer, and then placed in a battery sintering furnace and sintered at 400-900°C to obtain the TOPCon battery cell, wherein the fine grid formed by the silver paste or aluminum paste is 15-40nm wide and 7-15nm high. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 1 is a graph showing the reflectivity (REFL)-wavelength of solar cells prepared in Example 1, Example 2, Example 3 and Comparative Example 1 of the present invention;

[0031] Figure 2 1 is an internal quantum efficiency (IQE)-wavelength graph of the solar cells prepared in Example 1, Example 2, Example 3 and Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0033] Example 1

[0034] A method for preparing a single-sided textured single-crystal silicon wafer comprises the following steps:

[0035] a. Liquid sodium silicate with a modulus of 3.0 was applied to the non-textured surface of a single-crystalline silicon wafer by spin coating (0.2 ml of liquid sodium silicate was applied at a rotation speed of 10 r / s) to obtain a sodium silicate layer with a thickness of 5 μm. The layer was then dried at 70°C for 1800 s to obtain a single-crystalline silicon wafer coated with the sodium silicate layer.

[0036] b. Texturing the textured surface of a single-crystalline silicon wafer coated with a sodium silicate layer, and then removing the sodium silicate layer by pickling to obtain a single-sided textured single-crystalline silicon wafer; wherein the texturing solution used for texturing is a NaOH solution with a volume fraction of 0.2%; the pickling method is as follows: immersing the single-crystalline silicon wafer coated with a sodium silicate layer in the pickling solution, wherein the concentration of HCl in the pickling solution is 0.28 mol / L and the concentration of HF is 0.58 mol / L.

[0037] The method for preparing TOPCon solar cells using the single-sided textured monocrystalline silicon wafer prepared by the above method comprises the following steps:

[0038] (1) In a high-temperature diffusion furnace, boron is diffused into a single-sided N-type substrate monocrystalline silicon wafer to form a PN junction, thereby obtaining a monocrystalline silicon wafer with a sheet resistance of 60 ohms / square meter.

[0039] (2) Using 3% by mass of HF, the surfaces of the single crystal silicon wafer prepared in step (1) except the textured surface are corroded.

[0040] (3) Using PECVD equipment, a 0.3 nm tunneling oxide layer is deposited on the surface of the single crystal silicon wafer prepared in step (2).

[0041] (4) Using PECVD equipment, an 80 nm polysilicon deposition layer is formed on the surface of the single crystal silicon wafer prepared in step (3), and phosphorus is diffused into the polysilicon deposition layer using LPCVD equipment.

[0042] (5) The single crystal silicon wafer prepared in step (4) is placed in an acid solution for cleaning, wherein the concentration of hydrochloric acid in the acid solution is 0.28 mol / L and the concentration of hydrofluoric acid is 0.58 mol / L.

[0043] (6) A 2 nm thick aluminum oxide film was prepared on the textured surface of the single crystal silicon wafer prepared in step (5) using a plate-type ALD device.

[0044] (7) Using plate-type PECVD, a silicon nitride anti-reflection layer with a thickness of 60 nm is deposited on the textured surface of the single-crystal silicon wafer prepared in step (6).

[0045] (8) Using plate-type PECVD, a silicon nitride layer with a passivation effect and a thickness of 50 nm is prepared on the non-textured surface of the single-crystal silicon wafer prepared in step (7).

[0046] (9) Sintering + printing treatment: The finished silver paste is printed on the textured surface and non-textured surface of the single crystal silicon wafer prepared in step (8) using a screen printing machine, and placed in a battery sintering furnace. The silver paste is lowered at 400°C to penetrate into the interior of the silicon wafer to form a solar cell. The fine grid formed by the silver paste is 15nm wide and 7nm high.

[0047] Example 2

[0048] A method for preparing a single-sided textured single-crystal silicon wafer comprises the following steps:

[0049] a. Liquid sodium silicate with a modulus of 3.3 was applied to the non-textured surface of a single-crystalline silicon wafer by spin coating (5 ml of liquid sodium silicate was applied at a rotation speed of 180 r / s) to obtain a sodium silicate layer with a thickness of 150 μm. The sodium silicate layer was then dried at 130°C for 60 seconds to obtain a single-crystalline silicon wafer coated with the sodium silicate layer.

[0050] b. Texturing the textured surface of a single-crystalline silicon wafer coated with a sodium silicate layer, and then removing the sodium silicate layer by pickling to obtain a single-sided textured single-crystalline silicon wafer; wherein the texturing solution used for texturing is a NaOH solution with a volume fraction of 0.2%; the pickling method is as follows: immersing the single-crystalline silicon wafer coated with a sodium silicate layer in the pickling solution, wherein the concentration of HCl in the pickling solution is 0.46 mol / L, and the concentration of HF is 0.98 mol / L.

[0051] The method for preparing TOPCon solar cells using the single-sided textured monocrystalline silicon wafer prepared by the above method comprises the following steps:

[0052] (1) In a high-temperature diffusion furnace, phosphorus is diffused into a single-sided textured P-type substrate monocrystalline silicon wafer to form a PN junction, thereby obtaining a monocrystalline silicon wafer with a sheet resistance of 200 ohms / square meter.

[0053] (2) Using HF with a mass fraction of 49%, the other surfaces of the single crystal silicon wafer prepared in step (1) except the PN junction are corroded.

[0054] (3) Using a PVD device, a 2.6 nm tunneling oxide layer is deposited on the surface of the single crystal silicon wafer prepared in step (2).

[0055] (4) Using PVD equipment, a 160 nm polysilicon deposition layer is formed on the surface of the single crystal silicon wafer prepared in step (3), and the polysilicon deposition layer is in-situ doped using PECVD equipment.

[0056] (5) The single crystal silicon wafer prepared in step (4) is placed in an acid solution for cleaning, wherein the concentration of hydrochloric acid in the acid solution is 0.86 mol / L and the concentration of hydrofluoric acid is 1.73 mol / L.

[0057] (6) Using a plate-type ALD device, a 10 nm thick aluminum oxide film is prepared on the textured surface of the single crystal silicon wafer prepared in step (5).

[0058] (7) Using plate-type PECVD, a silicon nitride anti-reflection layer with a thickness of 100 nm is deposited on the textured surface of the single-crystal silicon wafer prepared in step (6).

[0059] (8) Using plate-type PECVD, a silicon nitride layer with a passivation effect having a thickness of 95 nm is prepared on the non-textured surface of the single-crystal silicon wafer prepared in step (7).

[0060] (9) Sintering + printing treatment: The finished silver paste is printed on the textured surface and non-textured surface of the single crystal silicon wafer prepared in step (8) using a screen printing machine, and placed in a battery sintering furnace. The silver paste is lowered at 900°C to penetrate into the interior of the silicon wafer to form a solar cell. The fine grid formed by the silver paste is 40nm wide and 15nm high.

[0061] Example 3

[0062] A method for preparing a single-sided textured single-crystal silicon wafer comprises the following steps:

[0063] a. Liquid sodium silicate with a modulus of 3.7 was applied to the non-textured surface of a single-crystalline silicon wafer by spin coating (2.5 ml of liquid sodium silicate was applied at a rotation speed of 95 r / s) to obtain a sodium silicate layer with a thickness of 77 μm. The sodium silicate layer was then dried at 100°C for 930 seconds to obtain a single-crystalline silicon wafer coated with the sodium silicate layer.

[0064] b. Texturing the textured surface of a single-crystalline silicon wafer coated with a sodium silicate layer, and then removing the sodium silicate layer by pickling to obtain a single-sided textured single-crystalline silicon wafer; wherein the texturing solution used for texturing is a NaOH solution with a volume fraction of 0.2%; the pickling method is as follows: immersing the single-crystalline silicon wafer coated with a sodium silicate layer in the pickling solution, wherein the concentration of HCl in the pickling solution is 0.63 mol / L, and the concentration of HF is 1.37 mol / L.

[0065] The method for preparing TOPCon solar cells using the single-sided textured monocrystalline silicon wafer prepared by the above method comprises the following steps:

[0066] (1) In a high-temperature diffusion furnace, phosphorus is diffused into a single-sided textured P-type substrate monocrystalline silicon wafer to form a PN junction, thereby obtaining a monocrystalline silicon wafer with a sheet resistance of 130 ohms / square meter.

[0067] (2) Using HF with a mass fraction of 26%, the other surfaces of the single crystal silicon wafer prepared in step (1) except the PN junction are corroded.

[0068] (3) Using LPCVD equipment, a 1.5 nm tunneling oxide layer is deposited on the surface of the single crystal silicon wafer prepared in step (2).

[0069] (4) Using LPCVD equipment, a 120 nm polysilicon deposition layer is formed on the surface of the single crystal silicon wafer prepared in step (3), and the polysilicon deposition layer is in situ doped using PECVD equipment.

[0070] (5) The single crystal silicon wafer prepared in step (4) is placed in an acid solution for cleaning, wherein the concentration of hydrochloric acid in the acid solution is 0.57 mol / L and the concentration of hydrofluoric acid is 1.2 mol / L.

[0071] (6) A 6 nm thick aluminum oxide film was prepared on the textured surface of the single crystal silicon wafer prepared in step (5) using a plate-type ALD device.

[0072] (7) Using plate-type PECVD, a silicon nitride anti-reflection layer with a thickness of 80 nm is deposited on the textured surface of the single-crystal silicon wafer prepared in step (6).

[0073] (8) Using plate-type PECVD, a silicon nitride layer with a passivation effect having a thickness of 73 nm is prepared on the non-textured surface of the single-crystal silicon wafer prepared in step (7).

[0074] (9) Sintering + printing treatment: The finished silver paste is printed on the textured surface and the non-textured surface of the single crystal silicon wafer prepared in step (8) using a screen printing machine, and placed in a battery sintering furnace. The silver paste is lowered at 650°C to penetrate into the interior of the silicon wafer to form a solar cell. The fine grid formed by the silver paste is 40nm wide and 15nm high.

[0075] Comparative Example 1

[0076] A method for preparing a single-sided textured single-crystal silicon wafer comprises the following steps:

[0077] The chemicals were prepared in a mass ratio of 1:1:0.5:15 for silica powder: additive: lignocellulose: gum arabic and stirred at 60°C for 5 minutes to form a colloid solution. The additives were sodium benzoate and a fluorocarbon surfactant in a mass ratio of 1:6.

[0078] A 2 μm silicon oxide layer was prepared by applying a silicon oxide solution to the non-textured surface of a single crystal silicon wafer using a spin coating process.

[0079] The subsequent texturing, pickling and other process steps for preparing solar cell wafers are the same as those in Example 1.

[0080] Test Example 1

[0081] The spectral response performance of the solar cells prepared in Examples 1-3 and Comparative Example 1 was tested, and the reflectivity (REFL) of the solar cell and the internal quantum efficiency (IQE) of the solar cell were detected. The results are as follows: Figure 1 and Figure 2 shown.

[0082] from Figure 1 and Figure 2 It can be seen that when the wavelength is greater than 1000nm, the REFL and IQE of Examples 1-3 are higher than those of Comparative Example 1, indicating that the solar cell prepared by using the single-sided texturing of the sodium silicate layer on the single-sided silicon wafer has a higher photoelectric conversion efficiency for long-wavelength light.

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a single-sided textured single-crystal silicon wafer, characterized by: The process steps include: a. coating liquid sodium silicate on the non-textured surface of a single crystal silicon wafer and drying the wafer to obtain a single crystal silicon wafer coated with a sodium silicate layer; b. texturing the textured surface of the single-crystal silicon wafer coated with the sodium silicate layer, and then acid-washing to remove the sodium silicate layer, thereby obtaining a single-side textured single-crystal silicon wafer; In step a, the thickness of the sodium silicate layer is 5 μm-150 μm; In step a, the drying temperature is 70° C.-130° C., and the drying time is 60s-1800s.

2. The method for preparing a single-sided textured single-crystal silicon wafer according to claim 1, wherein: In step a, the modulus n of the liquid sodium silicate is ≥3.

3. The method for preparing a single-sided textured single-crystal silicon wafer according to claim 1, wherein: In step a, the coating method is one of spin coating, spray coating or brush coating.

4. The method for preparing a single-sided textured single-crystal silicon wafer according to claim 3, wherein: The spin coating speed is 10 r / s-180 r / s, and the glue drop amount is 0.2 mL-5 mL.

5. The method for preparing a single-sided textured single-crystal silicon wafer according to claim 1, wherein: In step b, the pickling method is: immersing the single crystal silicon wafer coated with the sodium silicate layer in a pickling solution; the concentration of HCl in the pickling solution is 0.28mol / L-0.63mol / L, and the concentration of HF is 0.58mol / L-1.37mol / L.

6. A single-sided textured single-crystalline silicon wafer produced by the method for producing a single-sided textured single-crystalline silicon wafer according to any one of claims 1 to 5.

7. A method for preparing a TOPCon cell, characterized in that: The following steps are involved: The single-sided texturized single-crystalline silicon wafer described in claim 6 is subjected to diffusion, BSG / PSG removal, tunnel oxide layer preparation, polysilicon deposition + phosphorus diffusion / in-situ doping, cleaning, front aluminum oxide deposition, front silicon nitride deposition, back silicon nitride deposition, printing + sintering treatment in sequence to obtain the TOPCon cell.

8. The method for preparing a TOPCon cell according to claim 7, wherein: The diffusion method comprises: performing boron diffusion or phosphorus diffusion on the single-side textured single-crystal silicon wafer in a high-temperature diffusion furnace to form a PN junction on the surface of the single-crystal silicon wafer; wherein, when the single-crystal silicon wafer is an N-type substrate, boron diffusion is performed; when the single-crystal silicon wafer is a P-type substrate, phosphorus diffusion is performed; and / or The method for removing BSG / PSG is: using a 3%-49% by mass HF solution to etch the surface of the diffused single crystal silicon wafer except the PN junction; and / or The method for preparing the tunnel oxide layer comprises: using a PECVD device, an LPCVD device or a PVD device to deposit a tunnel oxide layer on the surface of the single crystal silicon wafer, wherein the thickness of the tunnel oxide layer is 0.3-2.6 nm; and / or The polysilicon deposition + phosphorus diffusion / in-situ doping method comprises: sequentially performing polysilicon deposition and phosphorus diffusion / in-situ doping on the single crystal silicon wafer; wherein the polysilicon deposition method comprises: using PECVD equipment, LPCVD equipment or PVD equipment to prepare a polysilicon deposition layer on the surface of the single crystal silicon wafer, wherein the thickness of the polysilicon deposition layer is 80-160 nm; the phosphorus diffusion / in-situ doping method comprises: using PECVD equipment or PVD equipment to perform in-situ doping on the polysilicon deposition layer, or using LPCVD equipment to perform phosphorus diffusion on the polysilicon deposition layer; and / or The cleaning method comprises: placing the single crystal silicon wafer in an acid cleaning solution for cleaning, wherein the concentration of HCl in the acid cleaning solution is 0.28 mol / L-0.86 mol / L, and the concentration of HF is 0.58 mol / L-1.73 mol / L; and / or The method for depositing aluminum oxide on the textured surface comprises: using a plate-type ALD or a tube-type ALD device to deposit an aluminum oxide film on the textured surface of the single crystal silicon wafer, wherein the thickness of the aluminum oxide film is 2-10 nm; and / or The method for depositing silicon nitride on the textured surface comprises: using a plate-type PECVD or tube-type PECVD device to deposit a silicon nitride anti-reflection film on the textured surface of the single crystal silicon wafer, wherein the thickness of the silicon nitride anti-reflection film is 60-100 nm; and / or The method for depositing silicon nitride on the non-textured surface is: using a plate-type PECVD or tube-type PECVD device to deposit a silicon nitride film on the non-textured surface of the single crystal silicon wafer, wherein the thickness of the silicon nitride film is 50-95 nm; and / or The printing + sintering treatment method is: silver paste is printed on the non-textured surface of the single crystal silicon wafer by screen printing, and silver paste or aluminum paste is printed on the texturized surface of the single crystal silicon wafer, and then placed in a battery sintering furnace and sintered at 400-900°C to obtain the TOPCon battery cell.

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