Preparation method of TOPCon solar cell and TOPCon solar cell

Abstract

The invention provides a preparation method of a TOPCon solar cell and the TOPCon solar cell. The preparation method comprises the following steps: forming a SiCx layer through high-density plasma enhanced chemical vapor deposition; an a-Si layer is formed through high-density plasma enhanced chemical vapor deposition, and the SiCx layer and the a-Si layer form a double-layer passive film structure. The double-layer passivation film structure has improved compactness, is beneficial to control of a doping curve, further realizes beneficial regulation and control of the structure, the optical performance and the passivation effect of the deposition layer, and improves economic benefits.

Description

Technical Field

[0001] The present disclosure relates to the technical field of crystalline silicon solar cells, and particularly relates to a method for preparing a TOPCon solar cell and a TOPCon solar cell obtained by this method. Background Art

[0002] Compared with P-type cells, N-type cells are excellent in terms of stability and efficiency improvement due to their high minority carrier lifetime and no light-induced degradation. In particular, TOPCon cells reduce photocurrent loss and improve conversion efficiency by optimizing the back metal contact structure. The theoretical limit efficiency of TOPCon cells is as high as 28.7%.

[0003] In the conventional method for preparing TOPCon cells, there are problems such as slow deposition rate and ion damage, which affect the quality of the silicon thin film and the film-forming stability. Summary of the Invention

[0004] To overcome the above problems, in a first aspect, the present disclosure provides a method for preparing a TOPCon solar cell, including: forming a SiCx layer by high-density plasma-enhanced chemical vapor deposition; forming an a-Si layer by high-density plasma-enhanced chemical vapor deposition, wherein the SiCx layer and the a-Si layer form a double-layer passivation film structure. This passivation film has improved compactness, which is beneficial to the control of the doping curve, and thus can beneficially regulate the structure, optical properties, and passivation effect of the deposited layer, improving economic benefits.

[0005] In the method for preparing the TOPCon solar cell, the thickness of the SiCx layer in the double-layer passivation film structure is 2 - 30 nm.

[0006] In the method for preparing the TOPCon solar cell, the a-Si layer in the double-layer passivation film structure is an N-type amorphous silicon thin film with a thickness of 80 - 150 nm.

[0007] In the method for preparing the TOPCon solar cell, when forming the SiCx layer by high-density plasma-enhanced chemical vapor deposition, silane and methane are used as the source gases, and hydrogen is used as the carrier gas for high-density plasma-enhanced chemical vapor deposition, wherein the flow ratio of methane to silane is 1:1 to 1:3; the deposition temperature is 200°C to 400°C; the power density is 0.1 to 0.2 W / cm 2 ; the deposition time is 10 to 30 min.

[0008] In the method for preparing the TOPCon solar cell, when forming the a-Si layer by high-density plasma-enhanced chemical vapor deposition, silane and phosphine are used as source gases, the flow rate of silane is 500 sccm to 5000 sccm, the flow rate of phosphine is 100 sccm to 5000 sccm, the deposition temperature is 500 °C to 700 °C, and the deposition is carried out until the phosphorus doping concentration reaches 1E19 / cm 3 to 1E21 / cm 3 ; the annealing temperature is 700 °C to 900 °C.

[0009] In the method for preparing the TOPCon solar cell, before forming the SiCx layer by high-density plasma-enhanced chemical vapor deposition, it further includes cleaning and texturing the silicon substrate and forming a tunneling oxide layer on the back of the silicon substrate.

[0010] In the method for preparing the TOPCon solar cell, after forming the a-Si layer by high-density plasma-enhanced chemical vapor deposition, it further includes: performing a degree removal and a mask removal treatment on the silicon substrate; forming an AlOx layer on the front of the silicon substrate; forming SiNx layers on the front and back of the silicon substrate; and forming electrodes on the front and back of the silicon substrate.

[0011] In a second aspect, the present disclosure also provides a TOPCon solar cell, which is prepared according to the method for preparing the TOPCon solar cell described in the first aspect of the present disclosure, and includes a double-layer passivation film structure composed of a SiCx layer and an a-Si layer.

[0012] In some embodiments, the thickness of the SiCx layer in the double-layer passivation film structure is 2 - 30 nm.

[0013] In some embodiments, the a-Si layer in the double-layer passivation film structure is an N-type amorphous silicon thin film, and its thickness is 80 - 150 nm.

[0014] In the TOPCon solar cell of the present disclosure, the a-Si layer is an N-type amorphous silicon thin film.

[0015] In the method for preparing the TOPCon solar cell of the present disclosure, in the process of high-density plasma-enhanced chemical vapor deposition, the kinetic energy of plasma elements such as Si elements and C elements is small, and the bombardment of the tunneling SiOx by the particles is smaller, which is beneficial to the formation of a high-performance passivation contact; the double-layer passivation film structure composed of the SiCx layer and the a-Si layer obtained thereby has higher density and uniformity, which is beneficial to forming a good contact with the metal and reducing the carrier transport loss. Further, the high-density plasma-enhanced chemical vapor deposition technology has a fast deposition rate and a large production capacity, and has the advantage of mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a flowchart of an embodiment of a method for manufacturing a TOPCon solar cell according to the present disclosure.

[0017] Figure 2 It is a flowchart of another embodiment of a method for manufacturing a TOPCon solar cell according to the present disclosure.

[0018] Figure 3 It is a structural diagram of a solar cell according to the present disclosure. Detailed Embodiments

[0019] To enable those skilled in the art to better understand the technical solutions of the present disclosure, the technical solutions of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0020] Example embodiments will be described more fully hereinafter with reference to the accompanying drawings, but the example embodiments may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0021] In the case of no conflict, the various embodiments of the present disclosure and the various features in the embodiments may be combined with each other.

[0022] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0023] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. As used herein, the singular forms "a" and "the" are also intended to include the plural forms unless the context clearly indicates otherwise. It will also be understood that when the terms "comprises" and / or "consisting of" are used in this specification, it specifies the presence of the stated features, integers, steps, operations, elements and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0024] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted as having an idealized or overly formal meaning unless expressly so defined herein.

[0025] In the preparation method of traditional TOPCon cells, a passivation film is formed by plasma enhanced chemical vapor deposition (PECVD); however, PECVD has problems such as slow deposition rate and ion damage, which affect the quality of the silicon thin film and the film formation stability.

[0026] The present disclosure aims to provide a new method for preparing a TOPCon solar cell to improve the quality of the passivation film, thereby improving the performance of the solar cell.

[0027] The present disclosure provides a method for preparing a TOPCon solar cell, as Figure 1 shown, including:

[0028] S1. Forming a SiCx layer by high-density plasma-enhanced chemical vapor deposition;

[0029] S2. Forming an a-Si layer by high-density plasma-enhanced chemical vapor deposition, wherein the SiCx layer and the a-Si layer form a double-layer passivation film structure.

[0030] High-density plasma technology (HDPCVD / ICPCVD) can generate a high concentration of plasma. These plasmas have higher activity and energy, can promote effective collisions and chemical reactions between reaction gas molecules, thereby improving the deposition rate and film quality. At the same time, the atomic bonding mode can be regulated through process conditions to further affect the structure, optical properties, and electron transport of the deposited layer. Therefore, through the preparation method described in the present disclosure, a dense, uniform, and stable passivation film can be obtained in the solar cell, which is beneficial to the control of the doping curve, and further beneficial regulation of the structure, optical properties, and passivation effect of the deposited layer can be achieved, improving economic benefits.

[0031] In the method for preparing the TOPCon solar cell, the thickness of the SiCx layer in the SiCx and a-Si double-layer passivation film is 2 - 30 nm.

[0032] In the method for preparing the TOPCon solar cell, the a-Si layer in the SiCx and a-Si double-layer passivation film is an N-type amorphous silicon thin film, and its thickness is 80 - 150 nm.

[0033] In the method for preparing the TOPCon solar cell, when forming the SiCx layer by high-density plasma-enhanced chemical vapor deposition, silane and methane are used as source gases, and hydrogen is used as a carrier gas for high-density plasma-enhanced chemical vapor deposition, wherein the flow ratio of methane to silane is 1:1 to 1:3; the deposition temperature is 200°C to 400°C; the power density is 0.1 to 0.2 W / cm 2 ; the deposition time is 10 to 30 min.

[0034] In the method for preparing the TOPCon solar cell, when forming the a-Si layer by high-density plasma enhanced chemical vapor deposition, silane and phosphine are used as source gases, the flow rate of silane is 500 sccm to 5000 sccm, the flow rate of phosphine is 100 sccm to 5000 sccm, the deposition temperature is 500 °C to 700 °C, and the deposition is carried out until the phosphorus doping concentration reaches 1E19 / cm 3 to 1E21 / cm 3 ; the annealing temperature is 700 °C to 900 °C.

[0035] In the method for preparing the TOPCon solar cell, before forming the SiCx layer by high-density plasma enhanced chemical vapor deposition, it further includes cleaning and texturing the silicon substrate and forming a tunneling oxide layer on the back of the silicon substrate.

[0036] In the method for preparing the TOPCon solar cell, after forming the a-Si layer by high-density plasma enhanced chemical vapor deposition, it further includes:

[0037] Performing a degree removal and mask removal treatment on the silicon substrate;

[0038] Forming an AlOx layer on the front of the silicon substrate;

[0039] Forming SiNx layers on the front and back of the silicon substrate; and

[0040] Forming electrodes on the front and back of the silicon substrate.

[0041] According to an embodiment of the present disclosure, referring to Figure 2 , the method for preparing the TOPCon solar cell includes the following steps:

[0042] S11. Using an N-type silicon wafer as the silicon substrate, cleaning and texturing it;

[0043] S12. Forming a tunneling oxide layer on the back of the silicon substrate;

[0044] S13. Forming a SiCx layer on the back of the silicon substrate;

[0045] S14. Forming an a-Si layer on the back of the silicon substrate;

[0046] S15. Performing a degree removal and mask removal treatment on the silicon substrate;

[0047] S16. Forming an AlOx layer on the front of the silicon substrate;

[0048] S17. Forming SiNx layers on the front and back of the silicon substrate; and

[0049] S18. Forming electrodes on the front and back of the silicon substrate.

[0050] According to an embodiment of the present disclosure, in the step S11, an N-type silicon wafer with a thickness of 100 μm to 150 μm is selected as the silicon substrate, and the silicon wafer is cleaned with a mixed solution of an alkali and H 2 O 2 , and then the silicon wafer is subjected to double-sided texturing with a mixed solution of an alkali and a texturing additive. The alkali can be KOH or NaOH, and the weight loss during texturing is controlled between 0.2 g and 0.5 g. After cleaning and texturing, the surface texture size of the silicon wafer is 1.0 - 1.5 nm;

[0051] According to an embodiment of the present disclosure, in the step S12, a tunneling oxide layer can be formed on the back surface of the silicon substrate by any applicable vacuum technology. For example, thermal oxidation, PECVD, low-pressure chemical vapor deposition (LPCVD), high-temperature diffusion, magnetron sputtering, and physical vapor deposition (PVD) technologies can be used.

[0052] Specifically, a silicon dioxide layer is deposited and formed by PECVD technology in a tube furnace with a power of 20 KHz to 50 KHz, the furnace tube temperature is 300 °C to 600 °C, and the deposition time is 8 to 15 min.

[0053] According to an embodiment of the present disclosure, in the step S13, the process conditions for forming the SiCx layer on the back surface of the silicon wafer by high-density plasma-enhanced chemical vapor deposition include: using silane and methane as the source gases and hydrogen as the carrier gas for high-density plasma-enhanced chemical vapor deposition, wherein the flow ratio of methane to silane is 1:1 to 1:3; the deposition temperature is 200 °C to 400 °C; the power density is 0.1 to 0.2 W / cm 2 ; the deposition time is 10 to 30 min.

[0054] Specifically, the flow ratio of methane to silane in the mixed gas can be any value between 1:1 and 1:3, such as 1:1.2, 1:1.5, 1:2, 1:2.5, or 1:2.8, etc.

[0055] The deposition temperature can be any value between 200 °C and 400 °C, such as 225, 250, 275, 300, 325, 350, or 375 °C, etc.

[0056] The power density can be any value between 0.1 and 0.2 W / cm 2 , such as 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, or 0.19, etc.

[0057] The deposition time can be any value between 10 and 30 min, such as 12, 15, 18, 20, 22, 25, or 28 min, etc.

[0058] The thickness of the SiCx layer formed by high-density plasma enhanced chemical vapor deposition is 2 - 30 nm, such as 5, 10, 15, 20 or 25 nm, etc.

[0059] According to one embodiment of the present disclosure, in the S14 step, the process conditions for forming the a-Si layer on the back side of the silicon wafer by high-density plasma enhanced chemical vapor deposition include: using silane and phosphine as source gases, the flow rate of silane is 500 sccm to 5000 sccm, the flow rate of phosphine is 100 sccm to 5000 sccm, the deposition temperature is 500 °C to 700 °C, and the deposition is carried out until the phosphorus doping concentration reaches 1E19 / cm 3 to 1E21 / cm 3 ; the annealing temperature is 700 °C to 900 °C.

[0060] Specifically, the flow rate of silane can be any value between 500 sccm and 5000 sccm, such as 1000, 1500, 2000, 2500, 3000, 3500, 4000 or 4500 sccm, etc.

[0061] The flow rate of phosphine can be any value between 100 sccm and 5000 sccm, such as 500, 1000, 1500, 2000, 2500, 3000, 3500, 4000 or 4500 sccm, etc.

[0062] The deposition temperature can be any value between 500 °C and 700 °C, such as 525, 550, 575, 600, 625, 650 or 675 °C, etc.

[0063] The phosphorus doping concentration after deposition can be 1E19 / cm 3 、1E20 / cm 3 or 1E21 / cm 3 etc.

[0064] The annealing temperature can be any value between 700 °C and 900 °C, such as 725, 750, 775, 800, 825, 850 or 875 °C, etc.

[0065] The thickness of the a-Si layer formed by high-density plasma enhanced chemical vapor deposition is 90 to 180 nm, such as 95, 100, 125, 150 or 175 nm, etc.

[0066] According to an embodiment of the present disclosure, in the step S15, the silicon substrate is subjected to unwinding and demasking treatment by alkali washing and acid washing. Specifically, the silicon substrate can be treated with an alkali having a concentration of 2-3 wt% in an unwinding plating tank at a temperature of 60-80 °C for a treatment time of 100-150 s. Subsequently, the silicon substrate is treated with hydrofluoric acid / deionized water (HF / DI) in an acid cleaning tank to remove the BSG layer on the front side of the silicon wafer and the PSG layer on the back side of the silicon wafer.

[0067] According to an embodiment of the present disclosure, in the steps S16 and S17, an AlOx layer can be formed on the front side of the silicon substrate and a SiNx layer can be formed on the front and back sides of the silicon substrate by any applicable vacuum technology. For example, thermal oxidation, PECVD, low-pressure chemical vapor deposition (LPCVD), high-temperature diffusion, atomic layer deposition (ALD), magnetron sputtering, physical vapor deposition (PVD) technology, etc. can be used.

[0068] Specifically, the AlOx layer is deposited by ALD, and the thickness of the AlOx layer is 8 to 10 nm. The SiNx layer is formed on the front and back sides of the silicon substrate by PECVD. The thickness of the SiNx layer on the front side is 80 to 100 nm; the thickness of the SiNx layer on the back side is 80 to 120 nm.

[0069] According to an embodiment of the present disclosure, in the step S18, the silicon wafer is sequentially subjected to metallization + sintering + light / electrical injection treatment to form electrodes on the front and back sides of the silicon substrate, thereby obtaining the final finished cell.

[0070] Specifically, silver-aluminum paste can be used to print the positive electrode silver-aluminum grid lines on the front side of the silicon wafer, and silver paste can be used to print the negative electrode silver grid lines on the back side of the silicon wafer, and the solar cell is obtained by drying and sintering in the temperature range of 600 °C to 900 °C.

[0071] In a second aspect, the present disclosure also provides a TOPCon solar cell, which includes a SiCx and a-Si double-layer passivation film formed by high-density plasma-enhanced chemical vapor deposition.

[0072] In the TOPCon solar cell of the present disclosure, the a-Si layer is an N-type amorphous silicon thin film.

[0073] According to an embodiment of the present disclosure, referring to Figure 3 , the cell includes the following structure:

[0074] 1: N-type silicon wafer; 2: tunneling oxide layer (SiO 2 ); 3: SiCx layer; 4: n + -polycrystalline silicon thin film (n a-Si);

[0075] 5: p+ - Emitter; 6: SiNx layer; 7: AlOx layer; 8: Ag electrode; 9: Ag-Al electrode.

[0076] Compared with the prior art, in the preparation method of the TOPCon solar cell of the present disclosure, in the high-density plasma-enhanced chemical vapor deposition process, the kinetic energy of plasma elements such as Si elements and C elements is small, and the bombardment of tunneling SiOx by the particles is smaller, which is beneficial to the formation of high-performance passivation contacts; the obtained SiCx and a-Si double-layer passivation films have higher density and uniformity, which is beneficial to form good contacts with metals and reduce carrier transport losses. Further, the high-density plasma-enhanced chemical vapor deposition technology has a fast deposition rate and large production capacity, and has the advantage of mass production.

[0077] In order to enable those skilled in the art to more clearly understand the technical solution of the preparation method described in the present disclosure, the following specifically describes the technical solution of the preparation method described in the present disclosure through specific examples.

[0078] Example 1

[0079] S21. Select an N-type silicon wafer with a thickness of 120 μm as the silicon substrate, and perform cleaning and texturing. During the texturing process, maintain at 95 °C for 420 s in a mixed solution with a texturing additive concentration of 1 wt% and a KOH concentration of 0.05 wt%, and the surface size of the texture is 1.2 ± 0.05 nm;

[0080] S22. Use PECVD technology to deposit a silicon dioxide layer in a tube furnace with a power of 30 KHz. The temperature of the furnace tube is 400 °C, the deposition time is 10 min, and the thickness is 1.5 nm.

[0081] S23. Use HDPCVD to deposit a SiCx layer on the back of the silicon substrate, with the flow ratio of CH 4 and SiH 4 being 1:1.5; the deposition temperature is 300 °C; the power density is 0.12 W / cm 2 ; the deposition time is 10 min; the thickness of the obtained SiCx layer is 10 nm.

[0082] S24. Use HDPCVD to deposit an a-Si layer on the back of the silicon substrate in a tube-type phosphorus diffusion furnace. The flow rate of silane is 1000 sccm, the flow rate of phosphine is 2000 sccm, the deposition temperature is 700 °C, and the deposition is carried out until the phosphorus doping concentration reaches 1E20 / cm 3 ; the annealing temperature is 800 °C; the thickness of the obtained phosphorus-doped a-Si layer is 120 nm.

[0083] S25. Treat the silicon substrate with an alkali at a concentration of 3 wt% in the stripping bath at a temperature of 60 °C for 100 s. Subsequently, treat the silicon substrate with hydrofluoric acid / deionized water (HF / DI) in the acid cleaning bath to remove the BSG layer on the front side of the silicon wafer and the PSG layer on the back side of the silicon wafer.

[0084] S26. Deposit an AlOx layer by ALD method, and the thickness of the AlOx layer is 8 nm.

[0085] S27. Form a SiNx layer on the front and back sides of the silicon substrate by PECVD method. The thickness of the SiNx layer on the front side is 80 nm; the thickness of the SiNx layer on the back side is 100 nm.

[0086] S28. Print the positive electrode silver-aluminum grid lines on the front side of the silicon wafer with silver-aluminum paste, print the negative electrode silver grid lines on the back side of the silicon wafer with silver paste, and dry and sinter at 600 °C to obtain a solar cell wafer.

[0087] Example 2

[0088] S31. Select an N-type silicon wafer with a thickness of 120 μm as the silicon substrate and perform cleaning and texturing. During the texturing process, maintain at 95 °C for 420 s in a mixed solution with a texturing additive concentration of 1 wt% and a KOH concentration of 0.05 wt%, and the surface texture size is 1.2 ± 0.05 nm;

[0089] S32. Deposit a silicon dioxide layer by PECVD technology in a tube furnace with a power of 30 KHz. The temperature of the furnace tube is 400 °C, the deposition time is 10 min, and the thickness is 1.5 nm.

[0090] S33. Deposit a SiCx layer on the back side of the silicon substrate by HDPCVD, and the flow ratio of CH 4 to SiH 4 is 1:3; the deposition temperature is 400 °C; the power density is 0.15 W / cm 2 ; the deposition time is 12 min; the thickness of the obtained SiCx layer is 15 nm.

[0091] S34. Deposit an a-Si layer on the back side of the silicon substrate by HDPCVD in a tube-type phosphorus diffusion furnace. The flow rate of silane is 2000 sccm, the flow rate of phosphine is 3000 sccm, the deposition temperature is 600 °C, and deposit until the phosphorus doping concentration reaches 1E21 / cm 3 ; the annealing temperature is 900 °C; the thickness of the obtained phosphorus-doped a-Si layer is 100 nm.

[0092] S35. Treat the silicon substrate with an alkali at a concentration of 3 wt% in the stripping bath at a temperature of 60 °C for 100 s. Subsequently, treat the silicon substrate with hydrofluoric acid / deionized water (HF / DI) in the acid cleaning bath to remove the BSG layer on the front side of the silicon wafer and the PSG layer on the back side of the silicon wafer.

[0093] S36. Deposit an AlOx layer by ALD, and the thickness of the AlOx layer is 8 nm.

[0094] S37. Form a SiNx layer on the front and back sides of the silicon substrate by PECVD. The thickness of the SiNx layer on the front side is 80 nm; the thickness of the SiNx layer on the back side is 100 nm.

[0095] S38. Print the positive electrode silver-aluminum grid lines on the front side of the silicon wafer with silver-aluminum paste, print the negative electrode silver grid lines on the back side of the silicon wafer with silver paste, and dry and sinter at 700 °C to obtain a solar cell wafer.

[0096] Comparative Example 1

[0097] Prepare a solar cell in the same manner as in Example 1, except that the process conditions of the SiCx, a-Si double-layer passivation film are as follows:

[0098] Deposit a SiCx layer on the back side of the silicon wafer by PECVD, CH 4 and SiH 4 flow ratio of 1.5; deposition temperature of 400 °C; power density of 0.2 W / cm 2 ; deposition time of 10 min, thickness of 10 nm;

[0099] Similarly, deposit an amorphous silicon layer by PECVD, and then place it in a tube-type phosphorus diffusion furnace to obtain P-poly. The deposition temperature is 800 °C; deposit a phosphorus-doped polysilicon layer under the conditions of a silane flow rate of 1500 sccm and a phosphine flow rate of 2000 sccm until the phosphorus-doped concentration reaches 1E20 / cm 3 ; annealing temperature of 900 °C, thickness of 120 nm;

[0100] Comparative Example 2

[0101] Prepare a solar cell in the same manner as in Example 1, except that the SiCx film layer is not deposited.

[0102] Perform performance tests on the cells prepared in the examples and comparative examples. The electrical performance parameters of each cell are shown in Table 1 below.

[0103] Table 1: Comparison of electrical performance of solar cells in examples and comparative examples of the present disclosure

[0104] Number of samples Conversion efficiency % Voc_mV Isc_A FF_% Example 1 50 25.35 740.1 13.84 82.33 Example 2 50 25.38 740.1 13.82 83.01 Comparative Example 1 50 25.26 738.1 13.76 81.17 Comparative Example 2 50 25.30 739.3 13.80 81.76

[0105] As can be observed from Table 1, the TOPCon cells with the SiCx, a-Si double-layer passivation film structure obtained by the preparation method of the present disclosure have obvious advantages in electrical performance. Compared with Comparative Example 1, the efficiency is increased by at least 0.09%, and the FF is increased by about 1.16%; compared with Comparative Example 2, the efficiency is increased by at least 0.05%, and the FF is increased by about 0.57%. Thus, it can be seen that the solar cells obtained according to the preparation method of the present disclosure can significantly improve efficiency and reduce costs.

[0106] This document has disclosed exemplary embodiments, and although specific terms are used, they are used only and should be construed only as general illustrative meanings and not for the purpose of limitation. In some instances, it will be apparent to those skilled in the art that, unless otherwise expressly stated, features, characteristics, and / or elements described in connection with a particular embodiment may be used alone or in combination with features, characteristics, and / or elements described in connection with other embodiments. Accordingly, those skilled in the art will understand that various forms and details changes can be made without departing from the scope of the present disclosure as set forth by the appended claims.

Claims

1. A method for preparing a TOPCon solar cell, comprising: Forming a SiCx layer by high-density plasma enhanced chemical vapor deposition; An a-Si layer is formed by high-density plasma enhanced chemical vapor deposition, wherein the SiCx layer and the a-Si layer constitute a double-layer passivation film structure.

2. The preparation method according to claim 1, wherein The thickness of the SiCx layer in the double-layer passivation film structure is 2-30 nm.

3. The preparation method according to claim 1, wherein The a-Si layer in the double-layer passivation film structure is an N-amorphous silicon film with a thickness of 80-150 nm.

4. The preparation method according to claim 1, wherein When forming the SiCx layer by high-density plasma enhanced chemical vapor deposition, silane and methane are used as raw material gases and hydrogen is used as carrier gas for high-density plasma enhanced chemical vapor deposition, wherein the flow ratio of methane to silane is 1:1 to 1:3; the deposition temperature is 200°C to 400°C; the power density is 0.1 to 0.2 W / cm 2 ; The deposition time is 10 to 30 minutes.

5. The preparation method according to claim 1, wherein When forming an a-Si layer by high-density plasma enhanced chemical vapor deposition, silane and phosphine are used as raw material gases, the silane flow rate is 500 sccm to 5000 sccm, the phosphine flow rate is 100 sccm to 5000 sccm, the deposition temperature is 500°C to 700°C, and the deposition is performed until the phosphorus doping concentration reaches 1E19 / cm 3 To 1E21 / cm 3 ; The annealing temperature is 700℃ to 900℃.

6. The preparation method according to any one of claims 1 to 5, wherein: Before forming the SiCx layer by high-density plasma enhanced chemical vapor deposition, the preparation method further comprises: Cleaning and texturing the silicon substrate; and A tunneling oxide layer is formed on the back side of the silicon substrate.

7. The preparation method according to any one of claims 1 to 5, wherein: After forming the a-Si layer by high-density plasma enhanced chemical vapor deposition, the preparation method further comprises: De-wrap and remove masking of silicon substrate; forming an AlOx layer on the front side of the silicon substrate; forming SiNx layers on the front and back sides of the silicon substrate; and Electrodes are formed on the front and back sides of the silicon substrate.

8. A TOPCon solar cell, wherein the TOPCon solar cell is manufactured according to the method for manufacturing a TOPCon solar cell according to any one of claims 1 to 7, and comprises a double-layer passivation film structure consisting of a SiCx layer and an a-Si layer.

9. The TOPCon solar cell according to claim 8, wherein: The thickness of the SiCx layer in the double-layer passivation film structure is 2-30 nm.

10. The TOPCon solar cell according to claim 9, wherein: The a-Si layer in the double-layer passivation film structure is an N-amorphous silicon film with a thickness of 80-150 nm.

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