N-p type pecvd-silicon-based thin film and passivation process optimization method thereof

Abstract

This invention provides an N-P type PECVD-silicon-based thin film and its passivation process optimization method, belonging to the field of solar cell technology. The method includes texturing an N-type silicon substrate A using etching to obtain a pyramidal textured surface; sequentially washing, cleaning, re-washing, and drying the pyramidal textured surface to obtain an N-type silicon substrate B; fabricating an intrinsic amorphous silicon thin film C on one side of the N-type silicon substrate B using PECVD deposition; fabricating an intrinsic amorphous silicon thin film D on the other side of the N-type silicon substrate B using PECVD deposition; further fabricating an N-type amorphous silicon thin film on the intrinsic amorphous silicon thin film C using PECVD deposition and then oriented it for crystallization; and further fabricating a P-type amorphous silicon thin film on the intrinsic amorphous silicon thin film D using PECVD deposition and then oriented it for crystallization, resulting in a crystallized N-P type PECVD-silicon-based thin film. This invention can reduce the dehydrogenation effect that may occur during the growth of the doped microcrystalline thin film in the intrinsic passivation layer, thereby improving the conversion efficiency.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, specifically to an NP-type PECVD-silicon-based thin film and its passivation process optimization method. Background Technology

[0002] PECVD technology utilizes low-temperature plasma as an active particle source to deposit thin films on substrate surfaces through chemical reactions. This process not only effectively controls the composition, structure, and properties of the thin films but also offers advantages such as high efficiency, uniformity, and environmental friendliness. In the photovoltaic field, PECVD technology is widely used in the preparation of key materials for solar panels, such as anti-reflective films and transparent conductive films, and is of great significance for improving photoelectric conversion efficiency.

[0003] However, there are still some problems to be solved in the PECVD silicon-based thin film passivation process to improve process efficiency and product quality. These problems include: improper control of process parameters may lead to unstable film quality, affecting the performance of solar cells; low activation rate of dopants in the film results in low conductivity of the film, affecting the carrier transport efficiency; poor contact characteristics between the film and TCO (transparent conductive oxide) film may lead to increased contact loss and reduced conversion efficiency of solar cells. Summary of the Invention

[0004] The purpose of this invention is to provide an NP-type PECVD-silicon-based thin film and its passivation process optimization method to overcome the problems existing in the prior art. This invention can broaden the optical bandgap to enhance light absorption reaching the crystalline silicon substrate, thereby increasing the short-circuit current of the solar cell. At the same time, it ensures the crystallinity ratio of the thin film and improves the doping efficiency to ensure the effective transport of charge carriers, thereby improving the fill factor. By oriented crystallization, it can reduce the dehydrogenation effect that may occur in the intrinsic passivation layer during the growth of the doped microcrystalline thin film, ensuring excellent single-crystal silicon surface passivation. It can also further improve the contact with the doped layer, increase Voc and FF, and ultimately achieve the goal of improving conversion efficiency.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An optimization method for NP-type PECVD-silicon-based thin film passivation process includes the following steps: (1) A pyramid textured surface is obtained by etching on the surface of an N-type silicon substrate A. (2) The pyramid textured surface obtained in (1) is washed, cleaned, washed again and dried in sequence to obtain N-type silicon substrate B; (3) An intrinsic amorphous silicon thin film C is prepared on one side of an N-type silicon substrate B by PECVD deposition, and an intrinsic amorphous silicon thin film D is prepared on the other side of an N-type silicon substrate B by PECVD deposition. (4) On the intrinsic amorphous silicon thin film C obtained in (3), an N-type amorphous silicon thin film is prepared by PECVD deposition and then crystallized; on the intrinsic amorphous silicon thin film D obtained in (3), a P-type amorphous silicon thin film is prepared by PECVD deposition and then crystallized to obtain a crystallized NP-type PECVD-silicon-based thin film. Further, step (1) specifically involves cleaning the N-type silicon substrate A and using a potassium hydroxide solution to anisotropically etch the surface of the N-type silicon substrate A to form a pyramid-shaped textured surface structure. Furthermore, the cleaning process uses an SC1 solution; the concentration of the potassium hydroxide solution is 0.1-0.5 wt%. Further, step (2) specifically involves washing the pyramid velvet obtained in step (1) with deionized water, performing RCA cleaning, then washing again with deionized water, and then drying. Further, (3) specifically refers to: using PECVD deposition method, with silane and hydrogen as reaction gases, to prepare an intrinsic amorphous silicon thin film C on one side of an N-type silicon substrate B, and with silane and carbon dioxide as reaction gases, to prepare an intrinsic amorphous silicon thin film D on the other side of an N-type silicon substrate B; Furthermore, the specific process parameters for the PECVD deposition method are as follows: the gas flow ratio of silane to hydrogen is 1:(50~200); the gas flow ratio of silane to carbon dioxide is 1:(1~2); the process pressure is 500~600 mTorr; and the deposition temperature is 200~300 ℃. Further, in step (4), the N-type amorphous silicon thin film is prepared by PECVD deposition and crystallization is specifically as follows: PECVD deposition is carried out at a gas flow ratio of silane and hydrogen of 1:9, a process pressure of 500 mTorr, and a deposition temperature of 200℃, followed by annealing to obtain a crystallized N-type amorphous silicon thin film. Further, in step (4), the PECVD deposition method is used to continue preparing the P-type amorphous silicon thin film and to adjust the crystallization. Specifically, the PECVD deposition method is used at a gas flow ratio of silane and carbon dioxide of 1:1, a process pressure of 500 mTorr, and a deposition temperature of 200 °C. Then, annealing is performed to obtain a crystallized P-type amorphous silicon thin film. Furthermore, the annealing temperature is 800~900 ℃.

[0006] An NP-type PECVD-silicon-based thin film is obtained based on the above-mentioned optimized method for PECVD-silicon-based thin film passivation process.

[0007] The above technical solution has the following advantages or beneficial effects: This invention provides an NP-type PECVD-silicon-based thin film and its passivation process optimization method. Through the development of N-type nanocrystalline silicon-oxygen thin films, the optical bandgap is widened and the material quality is enhanced, effectively reducing parasitic absorption in the window layer and improving the collection efficiency of photogenerated carriers. The crystallization treatment of the P-type amorphous silicon thin film reduces carrier transport losses caused by defects and contact losses with the TCO film, improving the activation rate of dopants and the film's conductivity, further improving the contact characteristics with the TCO film, and contributing to increased fill factor and conversion efficiency. By adjusting the microstructure of the light-facing N-type silicon thin film towards nanocrystalline, the optical bandgap can be widened to enhance light absorption reaching the crystalline silicon substrate, thereby increasing the short-circuit current of the solar cell. Simultaneously, it can also ensure the crystallinity ratio of the film and improve the doping efficiency. The efficiency of dopant conversion ensures the effective transport of charge carriers, thereby improving the fill factor. By adjusting the microstructure of the p-type amorphous silicon thin film towards crystallinity, the carrier transport loss caused by defects in the p-type doped amorphous silicon thin film and the contact loss with the TCO film can be reduced, improving the activation rate of the dopant elements, giving the film high conductivity, and improving the contact characteristics with the TCO film, thus achieving the goal of improving the fill factor and conversion efficiency. Based on the crystallization of the N-type and P-type doped layer structures, and according to the changes in the N-type nanocrystal and P-type nanocrystal processes, the dehydrogenation effect that may occur in the intrinsic passivation layer during the growth of the doped layer microcrystalline thin film can be reduced, ensuring excellent single-crystal silicon surface passivation. At the same time, it can further improve the contact with the doped layer, increase Voc and FF, and achieve the goal of improving conversion efficiency.

[0008] Furthermore, the SC1 solution (typically composed of ammonia, hydrogen peroxide, and water) can effectively remove metallic impurities and organic contaminants from the silicon surface, providing a clean and contamination-free substrate for subsequent texturing processes.

[0009] Furthermore, by anisotropically etching the N-type silicon substrate A with potassium hydroxide solution, a pyramid-shaped textured structure was formed, which significantly increased the roughness of the silicon surface, thereby more effectively capturing and absorbing incident light. Compared with a smooth silicon surface, the pyramid textured surface can reduce light reflection and improve the light absorption efficiency in silicon materials.

[0010] Furthermore, the initial washing of the pyramid textured surface with deionized water helps remove residual potassium hydroxide solution and other impurities from the texturing process. The subsequent RCA cleaning can more thoroughly remove metal ions, organic matter, and other contaminants from the silicon surface. The second washing with deionized water ensures that all cleaning solutions are thoroughly rinsed off to avoid interfering with subsequent processes. The drying process ensures that the silicon surface is dry and anhydrous before film deposition. A wet surface can affect the growth and crystallization of the film during PECVD deposition, while a dry surface is conducive to the formation of a uniform and dense film layer, which helps to enhance the passivation effect, reduce surface recombination, and improve the open-circuit voltage (Voc) and fill factor (FF) of the solar cell.

[0011] Furthermore, intrinsic amorphous silicon thin films C and D were fabricated on both sides of an N-type silicon substrate B using PECVD deposition, achieving double-sided passivation of the silicon substrate. In the fabrication of intrinsic amorphous silicon thin film C, silane and hydrogen were selected as reactant gases. Silane is the main raw material for preparing amorphous silicon thin films, while the addition of hydrogen helps reduce dangling bonds and defects in the film, improving the quality and stability of the film. In the fabrication of intrinsic amorphous silicon thin film D, silane and carbon dioxide were selected as reactant gases. The introduction of carbon dioxide can adjust the chemical composition and microstructure of the film, which helps to further improve the passivation effect and electrical properties of the film.

[0012] Furthermore, by precisely controlling the gas flow ratio of silane and hydrogen, the hydrogen content in the thin film can be adjusted, thereby optimizing the microstructure and electrical properties of the film. An appropriate amount of hydrogen helps reduce dangling bonds and defects in the film, improving its density and stability. Adjusting the gas flow ratio of silane and carbon dioxide can affect the chemical composition and surface properties of the film; the introduction of carbon dioxide helps form oxygen-rich amorphous silicon films. A process pressure in the range of 500–600 mTorr ensures uniform distribution and effective mixing of the reactive gases within the PECVD chamber, thereby improving the deposition rate and film uniformity. A deposition temperature in the range of 200–300 °C ensures that the reactive gas molecules have sufficient energy for chemical reactions, while avoiding excessively high temperatures that could lead to a decrease in film quality. Optimized process parameters contribute to the formation of high-quality intrinsic amorphous silicon films, which can more effectively passivate defects and dangling bonds on the silicon surface, reducing surface recombination and thus improving the open-circuit voltage (Voc) and fill factor (FF) of the solar cell.

[0013] Furthermore, by preparing N-type amorphous silicon thin films using PECVD deposition at specific gas flow ratios, process pressures, and deposition temperatures, followed by annealing, the films can be oriented to crystallize. This improves the crystallinity of the films, reduces grain boundary scattering, and thus enhances their conductivity and carrier mobility. The oriented crystallized N-type amorphous silicon film, acting as a passivation layer, can more effectively passivate defects and dangling bonds on the silicon surface, reducing surface recombination and thereby increasing the open-circuit voltage (Voc) and fill factor (FF) of the solar cells. In addition, the crystallized film exhibits better thermal and chemical stability, contributing to extended solar cell lifespan.

[0014] Furthermore, by preparing P-type amorphous silicon thin films using PECVD deposition at specific gas flow ratios, process pressures, and deposition temperatures, films with excellent electrical properties can be obtained. The introduction of carbon dioxide helps to adjust the chemical composition and microstructure of the film, thereby improving its conductivity and stability. Subsequent annealing further promotes the orientation and crystallization of the film, improving its crystal quality and carrier mobility.

[0015] Furthermore, annealing at a high temperature of 800~900℃ helps the atoms in the amorphous silicon thin film to rearrange and form a more ordered crystal structure, which can significantly improve the conductivity and stability of the film, thereby improving the performance of the solar cell. By reducing defects and dangling bonds in the film, the annealed film can more effectively passivate defects on the silicon surface and reduce surface recombination, thereby improving the open-circuit voltage and fill factor of the solar cell.

[0016] The present invention also provides an NP-type PECVD-silicon-based thin film, which can effectively passivate defects and dangling bonds on the silicon surface, significantly reduce surface recombination, thereby improving the open-circuit voltage (Voc) and fill factor (FF) of the solar cell, and thus improving the photoelectric conversion efficiency of the solar cell. Attached Figure Description

[0017] Figure 1 This is a schematic flowchart of the NP-type PECVD-silicon-based thin film and its passivation process optimization method according to the present invention. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention. To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention. It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0019] Example 1: like Figure 1 As shown, this invention provides an NP-type PECVD-silicon-based thin film and its passivation process optimization method, comprising the following steps: (1) A pyramid textured surface is obtained by etching on the surface of an N-type silicon substrate A. Preferably, (1) specifically involves cleaning the N-type silicon substrate A and using a potassium hydroxide solution to anisotropically etch the surface of the N-type silicon substrate A to form a pyramid-shaped textured surface structure. Preferably, SC1 solution is used for cleaning; the concentration of potassium hydroxide solution is 0.1-0.5 wt%. (2) The pyramid textured surface obtained in (1) is washed with deionized water, subjected to RCA cleaning, then washed again with deionized water and dried to obtain N-type silicon substrate B. (3) Using PECVD deposition, silane and hydrogen are used as reaction gases to prepare an intrinsic amorphous silicon thin film C on one side of an N-type silicon substrate B, and silane and carbon dioxide are used as reaction gases to prepare an intrinsic amorphous silicon thin film D on the other side of an N-type silicon substrate B. Preferably, the process parameters for PECVD deposition are as follows: the gas flow ratio of silane to hydrogen is 1:(50~200); the gas flow ratio of silane to carbon dioxide is 1:(1~2); the process pressure is 500~600 mTorr; and the deposition temperature is 200~300 ℃. (4) On the intrinsic amorphous silicon thin film C obtained in (3), an N-type amorphous silicon thin film is further prepared by PECVD deposition at a gas flow ratio of silane and hydrogen of 1:9, a process pressure of 500 mTorr, and a deposition temperature of 200℃. Then, an annealing treatment is performed to obtain a crystallized N-type amorphous silicon thin film. On the intrinsic amorphous silicon thin film D obtained in S3, a P-type amorphous silicon thin film is further prepared by PECVD deposition at a gas flow ratio of silane and carbon dioxide of 1:1, a process pressure of 500 mTorr, and a deposition temperature of 200℃. Then, an annealing treatment is performed to obtain a crystallized P-type amorphous silicon thin film.

[0020] Preferably, the annealing temperature is 800~900 ℃.

[0021] The present invention also provides an NP-type PECVD-silicon-based thin film, which is obtained based on the above-mentioned optimized method for PECVD-silicon-based thin film passivation process.

[0022] Example 2: like Figure 1 As shown, this invention provides an NP-type PECVD-silicon-based thin film and its passivation process optimization method, comprising the following steps: (1) The N-type silicon substrate A was cleaned with SC1 solution and the surface of the N-type silicon substrate A was anisotropically etched with a potassium hydroxide solution with a concentration of 0.1 wt% to form a pyramid-shaped textured surface structure. (2) The pyramid textured surface obtained in (1) is washed with deionized water, subjected to RCA cleaning, then washed again with deionized water and dried to obtain N-type silicon substrate B. (3) Using PECVD deposition, with silane and hydrogen as reactants, an intrinsic amorphous silicon thin film C is prepared on one side of an N-type silicon substrate B with a gas flow ratio of silane to hydrogen of 1:50, a process pressure of 500 mTorr, and a deposition temperature of 200 ℃; an intrinsic amorphous silicon thin film D is prepared on the other side of an N-type silicon substrate B with a gas flow ratio of silane to carbon dioxide of 1:1, a process pressure of 500 mTorr, and a deposition temperature of 200 ℃. (4) On the intrinsic amorphous silicon thin film C obtained in (3), an N-type amorphous silicon thin film is further prepared by PECVD deposition at a gas flow ratio of silane and hydrogen of 1:9, a process pressure of 500 mTorr, and a deposition temperature of 200 °C. Then, an annealing treatment is performed at 800 °C to obtain a crystallized N-type amorphous silicon thin film. On the intrinsic amorphous silicon thin film D obtained in S3, a P-type amorphous silicon thin film is further prepared by PECVD deposition at a gas flow ratio of silane and carbon dioxide of 1:1, a process pressure of 500 mTorr, and a deposition temperature of 200 °C. Then, an annealing treatment is performed at 800 °C to obtain a crystallized P-type amorphous silicon thin film.

[0023] Example 3: like Figure 1 As shown, this invention provides an NP-type PECVD-silicon-based thin film and its passivation process optimization method, comprising the following steps: (1) The N-type silicon substrate A was cleaned with SC1 solution and the surface of the N-type silicon substrate A was anisotropically etched with a potassium hydroxide solution with a concentration of 0.25 wt% to form a pyramid-shaped textured surface structure. (2) The pyramid textured surface obtained in (1) is washed with deionized water, subjected to RCA cleaning, then washed again with deionized water and dried to obtain N-type silicon substrate B. (3) Using PECVD deposition, with silane and hydrogen as reactants, an intrinsic amorphous silicon thin film C is prepared on one side of an N-type silicon substrate B with a gas flow ratio of silane to hydrogen of 1:100, a process pressure of 550 mTorr, and a deposition temperature of 250 ℃; an intrinsic amorphous silicon thin film D is prepared on the other side of an N-type silicon substrate B with a gas flow ratio of silane to carbon dioxide of 1:1.5, a process pressure of 550 mTorr, and a deposition temperature of 250 ℃. (4) On the intrinsic amorphous silicon thin film C obtained in (3), N-type amorphous silicon thin film is further prepared by PECVD deposition at a gas flow ratio of silane and hydrogen of 1:9, a process pressure of 500 mTorr, and a deposition temperature of 200 °C. Then, it is annealed at 850 °C to obtain a crystallized N-type amorphous silicon thin film. On the intrinsic amorphous silicon thin film D obtained in S3, P-type amorphous silicon thin film is further prepared by PECVD deposition at a gas flow ratio of silane and carbon dioxide of 1:1, a process pressure of 500 mTorr, and a deposition temperature of 200 °C. Then, it is annealed at 850 °C to obtain a crystallized P-type amorphous silicon thin film.

[0024] Example 4: like Figure 1As shown, this invention provides an NP-type PECVD-silicon-based thin film and its passivation process optimization method, comprising the following steps: (1) The N-type silicon substrate A was cleaned with SC1 solution and the surface of the N-type silicon substrate A was anisotropically etched with a 0.5 wt% potassium hydroxide solution to form a pyramid-shaped textured surface structure. (2) The pyramid textured surface obtained in (1) is washed with deionized water, subjected to RCA cleaning, then washed again with deionized water and dried to obtain N-type silicon substrate B. (3) Using PECVD deposition, with silane and hydrogen as reactants, an intrinsic amorphous silicon thin film C is prepared on one side of an N-type silicon substrate B with a gas flow ratio of silane to hydrogen of 1:200, a process pressure of 600 mTorr, and a deposition temperature of 300 ℃; an intrinsic amorphous silicon thin film D is prepared on the other side of an N-type silicon substrate B with a gas flow ratio of silane to carbon dioxide of 1:2, a process pressure of 600 mTorr, and a deposition temperature of 300 ℃. (4) On the intrinsic amorphous silicon thin film C obtained in (3), N-type amorphous silicon thin film is further prepared by PECVD deposition at a gas flow ratio of silane and hydrogen of 1:9, a process pressure of 500 mTorr, and a deposition temperature of 200 ℃. Then, it is annealed at 900 ℃ to obtain a crystallized N-type amorphous silicon thin film. On the intrinsic amorphous silicon thin film D obtained in S3, P-type amorphous silicon thin film is further prepared by PECVD deposition at a gas flow ratio of silane and carbon dioxide of 1:1, a process pressure of 500 mTorr, and a deposition temperature of 200 ℃. Then, it is annealed at 900 ℃ to obtain a crystallized P-type amorphous silicon thin film.

[0025] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An optimization method for NP-type PECVD-silicon-based thin film passivation process, characterized in that, Includes the following steps: S1, texturing is performed on the surface of N-type silicon substrate A using an etching method to obtain a pyramidal textured surface; S2, the pyramid textured surface obtained in S1 is washed, cleaned, washed again and dried in sequence to obtain N-type silicon substrate B; S3, an intrinsic amorphous silicon thin film C is prepared on one side of an N-type silicon substrate B by PECVD deposition, and an intrinsic amorphous silicon thin film D is prepared on the other side of the N-type silicon substrate B by PECVD deposition. S4. On the intrinsic amorphous silicon thin film C obtained in S3, an N-type amorphous silicon thin film is further prepared by PECVD deposition and then oriented to crystallize; on the intrinsic amorphous silicon thin film D obtained in S3, a P-type amorphous silicon thin film is further prepared by PECVD deposition and then oriented to crystallize, resulting in a crystallized NP-type PECVD-silicon-based thin film.

2. The method for optimizing NP-type PECVD-silicon-based thin film passivation process according to claim 1, characterized in that, S1 specifically involves cleaning the N-type silicon substrate A and using a potassium hydroxide solution to perform anisotropic etching on the surface of the N-type silicon substrate A to form a pyramid-shaped textured surface structure.

3. The method for optimizing NP-type PECVD-silicon-based thin film passivation process according to claim 2, characterized in that, The cleaning was performed using SC1 solution; the concentration of the potassium hydroxide solution was 0.1-0.5 wt%.

4. The method for optimizing NP-type PECVD-silicon-based thin film passivation process according to claim 1, characterized in that, S2 specifically involves washing the pyramid-shaped velvet surface obtained in S1 with deionized water, performing RCA cleaning, then washing it again with deionized water, and finally drying it.

5. The method for optimizing NP-type PECVD-silicon-based thin film passivation process according to claim 1, characterized in that, Specifically, S3 involves: using PECVD deposition with silane and hydrogen as reaction gases to prepare an intrinsic amorphous silicon thin film C on one side of an N-type silicon substrate B, and using silane and carbon dioxide as reaction gases to prepare an intrinsic amorphous silicon thin film D on the other side of the N-type silicon substrate B.

6. The method for optimizing NP-type PECVD-silicon-based thin film passivation process according to claim 5, characterized in that, The specific process parameters for the PECVD deposition method are as follows: the gas flow ratio of silane to hydrogen is 1:(50~200); the gas flow ratio of silane to carbon dioxide is 1:(1~2); the process pressure is 500~600 mTorr; and the deposition temperature is 200~300 ℃.

7. The method for optimizing NP-type PECVD-silicon-based thin film passivation process according to claim 1, characterized in that, In step S4, N-type amorphous silicon thin films are further prepared by PECVD deposition and crystallization. Specifically, PECVD deposition is performed at a gas flow ratio of silane to hydrogen of 1:9, a process pressure of 500 mTorr, and a deposition temperature of 200°C. Then, annealing is carried out to obtain crystallized N-type amorphous silicon thin films.

8. The method for optimizing NP-type PECVD-silicon-based thin film passivation process according to claim 1, characterized in that, In step S4, the P-type amorphous silicon thin film is further prepared by PECVD deposition and crystallization. Specifically, PECVD deposition is performed at a gas flow ratio of silane to carbon dioxide of 1:1, a process pressure of 500 mTorr, and a deposition temperature of 200 °C. Then, annealing is carried out to obtain a crystallized P-type amorphous silicon thin film.

9. An optimization method for NP-type PECVD-silicon-based thin film passivation process according to claim 7 or 8, characterized in that, The annealing temperature is 800~900 ℃.

10. An NP-type PECVD-silicon-based thin film, characterized in that, This method is based on the PECVD-silicon-based thin film passivation process optimization method described in any one of claims 1-9.

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