Preparation method of TBC solar cell

Abstract

The invention discloses a preparation method of a TBC solar cell, and the method comprises the steps: immersing a substrate in a preset temperature, carrying out the texturing of the substrate and a specified solution, and controlling the texturing time within a preset time; sequentially depositing a tunneling oxide layer and an intrinsic polycrystalline silicon layer on the back surface of the substrate; depositing a mask layer on one side, far away from the tunneling oxide layer, of the intrinsic polycrystalline silicon layer; forming a first opening region on the mask layer, and carrying out boron expansion propulsion on the first opening region to form a boron-doped polycrystalline silicon layer; forming a second opening region on the mask layer, and carrying out phosphorus diffusion propulsion on the second opening region to form a phosphorus-doped polycrystalline silicon layer; the mask layer is left between the first opening area and the second opening area; and depositing an anti-reflection layer on the back surface of the substrate. The production process can be shortened, and the risk of laser damage to the battery is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of solar cell manufacturing, and in particular to a method for preparing a TBC solar cell. Background Art

[0002] Double-sided contact solar cells PERC (Passivated Emitter and Rear Cell), TOPCon (Tunnel Oxide Passivated Contact) and HJT (Heterojunction with Intrinsic Thin-layer) are all blocked by metal grid lines on the front, so part of the incident light cannot be absorbed, and the front appearance is not good. IBC (Interdigitated Back Contact Cell) places all the electrode grid lines on the back of the cell, so it has a higher short-circuit current Jsc. At the same time, the metal grid lines on the back can be widened to reduce the series resistance Rs, thereby increasing the fill factor FF, making this type of cell not only high in conversion efficiency, but also beautiful in appearance. In addition, the TBC (Tunneling Barrier Cell) cell, which is a superposition of TOPCon and BC (Buried Contact Technology) technology, has received widespread attention due to its greater potential for improving efficiency.

[0003] However, the TBC battery with back-side tunneling passivation structure still cannot be mass-produced due to its complex preparation process and high production cost. At present, the back structure of TBC battery involves a variety of combinations such as mask, laser and wet method, and the isolation problem between n-region and p-region is still significant. The production process is complicated and lengthy, which affects the battery production efficiency.

[0004] At present, most TBC preparation technologies use multi-step mask and printing slurry methods. For example, a laser is used to remove the n-region BSG (Borosilicate Glass) and then deposit poly (polycrystalline silicon) for P expansion (i.e., boron expansion), followed by a secondary laser to form an isolation region; or, in the prior art, phosphorus slurry and boron slurry are usually laser-transferred to the substrate, and then laser grooving is used to isolate the n-region and the p-region, but this method has a high slurry cost and a cumbersome process; or, in the prior art, multiple layers of mask layers are prepared separately and then removed to achieve the purpose of patterning the n-region and the p-region, but this method of multi-step mask removal is not only cumbersome in process and high in cost, but also cannot be mass-produced. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing a TBC solar cell, which can shorten the production process and reduce the risk of laser damage to the cell.

[0006] In order to solve the above technical problems, the present invention provides a method for preparing a TBC solar cell, comprising the following steps:

[0007] Immersing the substrate in a predetermined temperature and a specified solution for texturing, and the texturing time is controlled within a predetermined time;

[0008] Depositing a tunneling oxide layer and an intrinsic polysilicon layer in sequence on the back side of the substrate;

[0009] Depositing a mask layer on a side of the intrinsic polysilicon layer away from the tunnel oxide layer;

[0010] forming a first opening region on the mask layer, and performing boron diffusion on the first opening region to form a boron-doped polysilicon layer;

[0011] forming a second opening region on the mask layer, and performing phosphorus diffusion on the second opening region to form a phosphorus-doped polysilicon layer; the mask layer remains between the first opening region and the second opening region; and

[0012] An anti-reflection layer is deposited on the back side of the substrate.

[0013] Furthermore, the predetermined temperature is between 60°C and 80°C.

[0014] Furthermore, the designated solution includes KOH solution or NaOH solution.

[0015] Furthermore, the mass fraction of the KOH solution or the NaOH solution is 1% to 3%.

[0016] Furthermore, the predetermined time is within the range of 15 minutes to 25 minutes.

[0017] Furthermore, depositing a mask layer on a side of the intrinsic polysilicon layer away from the tunnel oxide layer specifically includes: preparing the mask layer on the intrinsic polysilicon layer by adopting a PECVD or LPCVD method.

[0018] Furthermore, the thickness of the mask layer is in the range of 150nm to 450nm.

[0019] Furthermore, the mask layer is made of silicon nitride material that is resistant to laser damage.

[0020] Furthermore, the forming of the first opening region on the mask layer specifically includes: using a picosecond green laser to make a groove in a p region of the mask layer to form the first opening region.

[0021] Furthermore, the boron diffusion is performed on the first opening area to form a boron-doped polysilicon layer, specifically including: a BSG layer is formed in the first opening area using a boron diffusion process, and after a first specified temperature diffusion process, the intrinsic polysilicon layer located between the first opening area and the tunneling oxide layer is converted into the boron-doped polysilicon layer.

[0022] Furthermore, the forming of the second opening region on the mask layer specifically includes: using a picosecond green laser to make a groove in the n region of the mask layer to form the first opening region.

[0023] Furthermore, the phosphorus diffusion is performed on the second opening area to form a phosphorus-doped polysilicon layer, specifically including: a PSG layer is formed in the second opening area using a phosphorus diffusion process, and after a second specified temperature diffusion process, the intrinsic polysilicon layer located between the second opening area and the tunneling oxide layer is changed into the phosphorus-doped polysilicon layer.

[0024] Furthermore, depositing the anti-reflection layer on the back side of the substrate specifically includes: removing the BSG layer and the PSG layer by chain cleaning, and then depositing the anti-reflection layer on the back side of the substrate.

[0025] Furthermore, the thickness of the anti-reflection layer is in the range of 40 nm to 90 nm.

[0026] Furthermore, the anti-reflection layer is made of silicon nitride.

[0027] Furthermore, the remaining mask layer has a length in the range of 40 μm to 80 μm.

[0028] Through the above technical solution, the present invention has the following beneficial effects:

[0029] The substrate is immersed in a predetermined temperature and a specified solution for texturing, and the texturing time is controlled within a predetermined time; a tunneling oxide layer and an intrinsic polysilicon layer are sequentially deposited on the back of the substrate; a mask layer is deposited on the side of the intrinsic polysilicon layer away from the tunneling oxide layer; a first opening area is formed on the mask layer, and a boron diffusion is performed on the first opening area to form a boron-doped polysilicon layer; a second opening area is formed on the mask layer, and a phosphorus diffusion is performed on the second opening area to form a phosphorus-doped polysilicon layer; a mask layer remains between the first opening area and the second opening area; and an anti-reflection layer is deposited on the back of the substrate. This method can shorten the production process and reduce the risk of laser damage to the battery; and the laser equipment can be compatible with each other, saving costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a flow chart of a method for preparing a TBC solar cell in one embodiment of the present invention;

[0031] Figure 2Schematic diagram of the structure of sequentially forming a tunnel oxide layer and an intrinsic polysilicon layer on the back side of a substrate in a method for preparing a TBC solar cell in one embodiment of the present invention;

[0032] Figure 3 It is a structural schematic diagram of forming a mask layer in a method for preparing a TBC solar cell in one embodiment of the present invention;

[0033] Figure 4 It is a structural schematic diagram of forming a first opening area on a mask layer in a method for preparing a TBC solar cell according to an embodiment of the present invention;

[0034] Figure 5 A schematic diagram of a structure in which a BSG layer is formed in a first opening region in a method for preparing a TBC solar cell according to an embodiment of the present invention;

[0035] Figure 6 It is a structural schematic diagram of forming a second opening area on a mask layer in a method for preparing a TBC solar cell according to an embodiment of the present invention;

[0036] Figure 7 It is a structural schematic diagram of forming a PSG layer in the second opening area in a method for preparing a TBC solar cell in one embodiment of the present invention;

[0037] Figure 8 It is a schematic structural diagram of forming an anti-reflection layer on the back side of a substrate in a method for preparing a TBC solar cell in one embodiment of the present invention.

[0038] In the figure, 100, substrate; 1, tunneling oxide layer; 2, intrinsic polysilicon layer; 3, mask layer; 4, first opening area; 5, boron-doped polysilicon layer; 6, BSG layer; 7, second opening area; 8, phosphorus-doped polysilicon layer; 9, PSG layer; 10, anti-reflection layer. DETAILED DESCRIPTION

[0039] A method for preparing a TBC solar cell of the present invention will be described below in conjunction with a schematic diagram, wherein a preferred embodiment of the present invention is shown. It should be understood that those skilled in the art can modify the present invention described herein while still achieving the advantageous effects of the present invention. Therefore, the following description should be understood as being widely known to those skilled in the art and not as a limitation of the present invention.

[0040] The serial numbers of the components herein, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings). In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc. are based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0041] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0042] The present invention is described in more detail in the following paragraphs by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that the drawings are in very simplified form and in non-precise proportions, and are only used to facilitate and clearly assist in illustrating the purpose of the embodiments of the present invention.

[0043] like Figure 1-8 As shown, the embodiment of the present invention provides a method for preparing a TBC solar cell, comprising the following steps:

[0044] S1, immersing the substrate 100 in a predetermined temperature and a specified solution for texturing, and the texturing time is controlled within a predetermined time;

[0045] S2, depositing a tunneling oxide layer 1 and an intrinsic polysilicon layer 2 in sequence on the back side of the substrate 100;

[0046] S3, depositing a mask layer 3 on a side of the intrinsic polysilicon layer 2 away from the tunnel oxide layer 1;

[0047] S4, forming a first opening region 4 on the mask layer 3, and performing boron diffusion on the first opening region 4 to form a boron-doped polysilicon layer 5;

[0048] S5, forming a second opening area 7 on the mask layer 3, and performing phosphorus diffusion on the second opening area 7 to form a phosphorus-doped polysilicon layer 8; the mask layer 3 remains between the first opening area 4 and the second opening area 7; and

[0049] S6, depositing an anti-reflection layer 10 on the back side of the substrate 100.

[0050] Wherein, the predetermined temperature is between 60°C and 80°C.

[0051] Preferably, the designated solution includes a KOH solution or a NaOH solution. Since the KOH solution or the NaOH solution can be recovered and reused in a closed-loop system, the chemical texturing process using the KOH solution or the NaOH solution can be more environmentally friendly.

[0052] Furthermore, the mass fraction of the KOH solution or the NaOH solution is 1% to 3%. Those skilled in the art will appreciate that the mass fraction of the KOH solution or the NaOH solution can also be selected and set according to actual needs.

[0053] In this embodiment, the predetermined time is within the range of 15min-25min. Appropriate time control can ensure that the surface of the silicon wafer reaches the ideal roughness, which can effectively reduce reflection and avoid absorption loss caused by excessive roughness. Too long texturing time may cause excessive corrosion and loss of the silicon wafer (substrate 100). Appropriate time control can reduce such loss and extend the service life of the silicon wafer (substrate 100). The texturing time range of 15min-25min is sufficient to complete the surface modification of the silicon wafer (substrate 100), while ensuring high production efficiency and avoiding unnecessary extension of waiting time. In addition, within the predetermined texturing time range, the stability of the process can be ensured and the process deviation caused by time fluctuations can be reduced.

[0054] In addition, those skilled in the art will appreciate that the scheduled time may also be set according to actual needs.

[0055] In S1, Figure 2 As shown, PEALD (Plasma Enhanced Atomic Layer Deposition) is specifically used to form the tunnel oxide layer 1, and this process is performed at a certain deposition temperature. The deposition temperature can be set according to actual needs.

[0056] In S2, if Figure 3As shown, the mask layer 3 is deposited on the side of the intrinsic polysilicon layer 2 away from the tunnel oxide layer 1, specifically including: preparing the mask layer 3 on the intrinsic polysilicon layer 2 by using PECVD (Plasma Enhanced Chemical Vapor Deposition) or LPCVD (Low Pressure Chemical Vapor Deposition) method.

[0057] In this embodiment, the thickness of the mask layer 3 is in the range of 150 nm to 450 nm, for example, the thickness of the mask layer 3 is 150 nm or 450 nm, so as to be applicable to different process requirements, enhance etching selectivity, and also improve pattern uniformity.

[0058] Preferably, the mask layer 3 is made of silicon nitride material that is resistant to laser damage, thereby improving processing accuracy and production efficiency.

[0059] In S3, such as Figure 4 As shown, the first opening area 4 is formed on the mask layer 3, specifically including: using a picosecond green laser to groove the p-region of the mask layer 3 to form the first opening area 4 (the outside of the p-region is not affected by the boron element due to the existence of the remaining mask layer 3). The use of a picosecond green laser can provide a high-precision and low-damage processing effect, and can also improve the performance and reliability of the finished product.

[0060] In S3, such as Figure 5 As shown, the boron diffusion is performed on the first opening area 4 to form a boron-doped polysilicon layer 5, specifically including: a BSG layer 6 (boron-doped silicon glass layer) is formed in the first opening area 4 using a boron diffusion process, and after a first specified temperature is applied, the intrinsic polysilicon layer 2 located between the first opening area 4 and the tunneling oxide layer 1 is converted into the boron-doped polysilicon layer 5.

[0061] The first designated temperature may be set according to actual needs.

[0062] In addition, the BSG layer 6 is formed in the first opening region 4 by using a boron diffusion process, which helps to improve the performance, stability and reliability of the finished product, and also helps to optimize production efficiency and cost control.

[0063] In S4, Figure 6As shown, the second opening area 7 is formed on the mask layer 3, specifically including: using a picosecond green laser to groove the n-region of the mask layer 3 to form the second opening area 7 (due to the existence of the remaining mask layer 3, the intrinsic polysilicon layer 2 between the remaining mask layer 3 and the tunneling oxide layer 1 is not affected by the phosphorus element). The use of a picosecond green laser can provide a high-precision and low-damage processing effect, and can also improve the performance and reliability of the finished product.

[0064] In S4, Figure 7 As shown, the phosphorus diffusion process is performed on the second opening area 7 to form the phosphorus-doped polysilicon layer 8, specifically including: using a phosphorus diffusion process to form a PSG layer 9 (phosphorus-doped silicon glass layer, Phosphorus-Doped Silicon Glass) in the second opening area 7, and after a second specified temperature is applied, the intrinsic polysilicon layer 2 located between the second opening area 7 and the tunneling oxide layer 1 is converted into the phosphorus-doped polysilicon layer 8.

[0065] The second designated temperature can be set according to actual needs.

[0066] In addition, the formation of the PSG layer 9 in the second opening area 7 by the phosphorus diffusion process and the advancement of the treatment by the second specified temperature can help improve the performance, stability and reliability of the finished product, and also help optimize production efficiency and cost control.

[0067] In this embodiment, the remaining mask layer 3 is located between the n region and the p region to isolate the n region from the p region.

[0068] By providing an isolation layer (i.e., the remaining mask layer 3) between the n-region and the p-region, it is possible to prevent current from flowing directly from the n-region to the p-region, thereby avoiding the occurrence of a short circuit phenomenon; it is also possible to improve the switching characteristics of the TBC solar cell (i.e., the finished product), reduce leakage current, and thus improve the overall performance of the TBC solar cell. By providing an isolation layer between the n-region and the p-region, it is also possible to reduce the performance degradation of the TBC solar cell due to impurity diffusion or defects, thereby improving the long-term reliability of the TBC solar cell.

[0069] Preferably, the remaining mask layer 3 has a length in the range of 40 μm to 80 μm, which can reduce the number of adjustments during the production process and improve production efficiency.

[0070] Those skilled in the art will appreciate that the remaining length of the mask layer 3 may be set according to actual requirements to achieve optimal performance and reliability.

[0071] In S5, Figure 8As shown, an anti-reflection layer 10 is deposited on the back side of the substrate 100. The anti-reflection layer 10 is an optical coating used to reduce or eliminate reflection losses caused when light is reflected on the surface of a medium. Specifically, the process includes: removing the BSG layer 6 and the PSG layer 9 by chain cleaning (a multi-step cleaning process), and then depositing the anti-reflection layer 10 on the back side of the substrate 100.

[0072] In the solar cell, the deposition of the anti-reflection layer 10 can significantly improve the light absorption efficiency of the TBC solar cell and reduce the reflection of light on the surface of the TBC solar cell.

[0073] Preferably, the thickness of the anti-reflection layer 10 is in the range of 40nm to 90nm. Within this thickness range, the anti-reflection layer 10 can effectively reduce the reflection of incident light on the surface of the TBC solar cell, because the anti-reflection layer 10 of a specific thickness can cause the reflected light to phase shift, thereby interfering with the light that continues to propagate and canceling each other out. By reducing reflection, more light can enter the interior of the TBC solar cell and be absorbed by the active layer, thereby improving the overall light absorption rate and efficiency of the TBC solar cell. The thickness of the anti-reflection layer 10 can be optimized for light of a specific wavelength to achieve better spectral response, especially in solar cells, it can improve the absorption of sunlight of different wavelengths. By increasing the light absorption rate, the conversion efficiency of the solar cell can be directly improved, and for other photoelectric TBC solar cells, their responsiveness and sensitivity can be improved.

[0074] Those skilled in the art will appreciate that the thickness of the anti-reflection layer 10 can be set according to actual needs.

[0075] As a preferred embodiment, the anti-reflection layer 10 is made of SiNx (silicon nitride). By using SiNx as the material of the anti-reflection layer 10, it is possible to provide improvements in chemical stability, thermal stability and electrical performance while maintaining excellent optical performance.

[0076] In addition, this embodiment also provides a TBC solar cell, which is manufactured using the TBC solar cell manufacturing method as described above.

[0077] In this embodiment, first, the original n-type silicon wafer (i.e., substrate 100) is immersed in a KOH solution or a NaOH solution with a mass fraction of 1% to 3% and a temperature of 60°C to 80°C for texturing, and the texturing time is controlled to be 15 to 25 minutes. Then, as Figure 2 As shown, LP (Low Pressure Chemical Vapor Deposition) is used to form the tunnel oxide layer 1 and the first intrinsic polysilicon layer 2. Figure 3As shown, a mask layer 3 is prepared on the intrinsic polysilicon layer 2 by using a PECVD or LPCVD method. The thickness of the mask layer 3 is 150nm to 450nm. The mask layer 3 can be made of a material resistant to laser damage such as silicon nitride. Figure 4 As shown, a picosecond green laser is used to form a first opening region 4 in the p region of the mask layer 3; Figure 5 As shown, a conventional boron diffusion process is used to form a BSG layer 6 in the first opening region 4 and after being pushed to a first specified temperature, the intrinsic polysilicon layer 2 between the first opening region 4 and the tunnel oxide layer 1 is transformed into a boron-doped polysilicon layer 5. Figure 6 As shown, a picosecond green laser is used to form a second opening area 7 in the n region of the mask layer 3; Figure 7 As shown, a conventional phosphorus diffusion process is used to form a PSG layer 9 in the second opening region 7 and after being pushed to a second specified temperature, the intrinsic polysilicon layer 2 between the second opening region 7 and the tunnel oxide layer 1 is transformed into a phosphorus-doped polysilicon layer 8. Figure 8 As shown, the BSG layer 6 and the PSG layer 9 on the back side are removed by chain cleaning, and then an anti-reflection layer 10 is deposited on the back side of the substrate 100, and the film thickness may be 40nm to 90nm.

[0078] In summary, the method for preparing a TBC solar cell proposed in the present invention has the following advantages:

[0079] The method comprises immersing the substrate in a predetermined temperature and a specified solution for texturing, and the texturing time is controlled within a predetermined time; depositing a tunneling oxide layer and an intrinsic polysilicon layer on the back of the substrate in sequence; depositing a mask layer on the side of the intrinsic polysilicon layer away from the tunneling oxide layer; forming a first opening area on the mask layer, and performing boron diffusion on the first opening area to form a boron-doped polysilicon layer; forming a second opening area on the mask layer, and performing phosphorus diffusion on the second opening area to form phosphorus-doped polysilicon; leaving a mask layer between the first opening area and the second opening area; and depositing an anti-reflection layer on the back of the substrate. The method can shorten the production process and reduce the risk of laser damage to the battery; and the laser equipment can be compatible with each other, saving costs.

[0080] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for preparing a TBC solar cell, characterized in that: These include: Immersing the substrate in a predetermined temperature and a specified solution for texturing, and the texturing time is controlled within a predetermined time; Depositing a tunneling oxide layer and an intrinsic polysilicon layer in sequence on the back side of the substrate; Depositing a mask layer on a side of the intrinsic polysilicon layer away from the tunnel oxide layer; forming a first opening region on the mask layer, and performing boron diffusion on the first opening region to form a boron-doped polysilicon layer; forming a second opening region on the mask layer, and performing phosphorus diffusion on the second opening region to form a phosphorus-doped polysilicon layer; the mask layer remains between the first opening region and the second opening region; and An anti-reflection layer is deposited on the back side of the substrate.

2. The method for preparing a TBC solar cell according to claim 1, characterized in that: The predetermined temperature is between 60°C and 80°C.

3. The method for preparing a TBC solar cell according to claim 1, characterized in that: The designated solution includes a KOH solution or a NaOH solution.

4. The method for preparing a TBC solar cell according to claim 3, characterized in that: The mass fraction of the KOH solution or the NaOH solution is 1% to 3%.

5. The method for preparing a TBC solar cell according to claim 1, characterized in that: The predetermined time is in the range of 15 min to 25 min.

6. The method for preparing a TBC solar cell according to claim 1, characterized in that: The step of depositing a mask layer on a side of the intrinsic polysilicon layer away from the tunnel oxide layer specifically includes: preparing the mask layer on the intrinsic polysilicon layer by adopting a PECVD or LPCVD method.

7. The method for preparing a TBC solar cell according to claim 6, characterized in that: The thickness of the mask layer is in the range of 150nm to 450nm.

8. The method for preparing a TBC solar cell according to claim 6, characterized in that: The mask layer is made of silicon nitride material that is resistant to laser damage.

9. The method for preparing a TBC solar cell according to claim 1, characterized in that: The forming of the first opening region on the mask layer specifically includes: using a picosecond green laser to make a groove in a p region of the mask layer to form the first opening region.

10. The method for preparing a TBC solar cell according to claim 9, characterized in that: The boron diffusion process on the first opening area to form a boron-doped polysilicon layer specifically includes: forming a BSG layer in the first opening area using a boron diffusion process, and after being diffused at a first specified temperature, the intrinsic polysilicon layer between the first opening area and the tunneling oxide layer becomes the boron-doped polysilicon layer.

11. The method for preparing a TBC solar cell according to claim 10, characterized in that: The forming of the second opening region on the mask layer specifically includes: using a picosecond green laser to make a groove in the n region of the mask layer to form the first opening region.

12. The method for preparing a TBC solar cell according to claim 11, characterized in that: The phosphorus diffusion process is performed on the second opening area to form a phosphorus-doped polysilicon layer, specifically comprising: forming a PSG layer in the second opening area using a phosphorus diffusion process, and after a second specified temperature diffusion process, the intrinsic polysilicon layer between the second opening area and the tunneling oxide layer becomes the phosphorus-doped polysilicon layer.

13. The method for preparing a TBC solar cell according to claim 12, wherein: The step of depositing the anti-reflection layer on the back side of the substrate specifically includes: removing the BSG layer and the PSG layer by chain cleaning, and then depositing the anti-reflection layer on the back side of the substrate.

14. The method for preparing a TBC solar cell according to claim 1, characterized in that: The thickness of the anti-reflection layer is in the range of 40nm to 90nm.

15. The method for preparing a TBC solar cell according to claim 1, characterized in that: The anti-reflection layer is made of silicon nitride.

16. The method for preparing a TBC solar cell according to claim 1, wherein: The remaining mask layer has a length ranging from 40 μm to 80 μm.

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