Plasma enhanced chemical vapor deposition (PECVD) process gradient laminated anti-reflection film and preparation method thereof

Abstract

The invention discloses a PECVD (Plasma Enhanced Chemical Vapor Deposition) process gradient laminated anti-reflection film and a preparation method thereof, and relates to the field of solar cells. The content of PECVD deposition components at the film layer junction of the gradient laminated anti-reflection film is gradually changed. The preparation method comprises the following steps: sequentially depositing the film layer I, the film layer II and the film layer III through a PECVD (Plasma Enhanced Chemical Vapor Deposition) method, namely starting auxiliary heating to preheat the furnace tube, starting vacuumizing, pre-depositing the film layer I, the film layer I, the film layer II and the film layer III, and evacuating residual gas in the furnace tube. Through the gradual change design of the laminated anti-reflection film, the refractive index between the film layers is changed in a gradient manner. Therefore, when light enters the solar cell, smooth transition between different film layers can be realized, and the reflection loss of the light is effectively reduced. Light reflection caused by sudden change of the refractive index at the junctions of the film layers made of different materials is avoided, the anti-reflection effect is improved, the light absorption rate is increased, the short-circuit current and the open-circuit voltage are increased, and the photoelectric conversion efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of solar cells, specifically to a graded multilayer antireflective film prepared by PECVD process and its preparation method. Background Technology

[0002] The core direction of current photovoltaic technology research and development lies in achieving breakthroughs in improving the cost-effectiveness of batteries, while the problem of surface optical loss urgently needs to be solved. The surface reflectivity of untreated crystalline silicon batteries can reach approximately 33%, which causes significant photon loss, directly leading to a reduction in photogenerated carrier generation and ultimately affecting photoelectric conversion efficiency. To address this technical bottleneck, optical functional film technology based on the principle of thin-film interference has shown significant application value. By constructing single-layer or multi-layer nanoscale thin-film structures on the battery surface, the phase of light waves can be effectively controlled, achieving destructive interference of reflected light. Silicon nitride, silicon oxynitride, and silicon oxide thin films are widely used as surface dielectric layers in the manufacturing process of solar cells. They can effectively passivate defects on the surface and within the silicon wafer and reduce the reflection of incident light. Employing a multi-layer gradient refractive index structure, the mixing ratio of high-refractive-index and low-refractive-index materials at the interface is changed to form a continuously varying refractive index distribution. The thickness of each layer is precisely designed (e.g., at the nanometer level) to achieve a broad-spectrum, omnidirectional anti-reflection effect, exhibiting excellent omnidirectional performance and a smooth change in reflectivity with varying incident angles.

[0003] Limitations of traditional multilayer antireflective films: Multilayer films with a fixed number of layers (such as double or triple layers) have a fixed refractive index for each layer. The antireflective effect is achieved by optimizing the layer thickness and material combination, but the refractive index changes discontinuously. The reflectivity increases significantly when incident at large angles, and the performance deteriorates significantly. Summary of the Invention

[0004] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a graded multilayer antireflective film for PECVD process and its preparation method, solving at least one technical problem mentioned in the background art.

[0005] (II) Technical Solution The technical solution adopted in this invention provides a PECVD process gradient stacked antireflective film, wherein the PECVD deposition component content at the film layer interface of the gradient stacked antireflective film is gradually changed.

[0006] Preferably, the gradual change in PECVD deposition composition at the membrane layer interface is specifically as follows: between adjacent membrane layers, the PECVD deposition composition content decreases in one membrane layer and increases in the other membrane layer.

[0007] Preferably, the gradient multilayer antireflective film includes a silicon nitride layer, a silicon oxynitride layer, and a silicon oxide layer.

[0008] Preferably, at the junction of the silicon nitride layer and the silicon oxynitride layer, the silicon nitride content deposited by PECVD decreases, while the silicon oxynitride content deposited by PECVD increases; at the junction of the silicon oxynitride layer and the silicon oxide layer, the silicon oxynitride content deposited by PECVD decreases, while the silicon oxide content deposited by PECVD increases.

[0009] On the other hand, a method for preparing a graded multilayer antireflective film using PECVD process is also provided, which involves sequentially depositing film layer one, film layer two, and film layer three using PECVD, including: turning on auxiliary heating to preheat the furnace tube and starting vacuuming, pre-depositing film layer one, depositing film layer one, depositing film layer two, depositing film layer three, and evacuating the residual gas in the furnace tube.

[0010] Preferably, the first film layer, the second film layer, and the third film layer are a silicon nitride layer, a silicon oxynitride layer, and a silicon oxide layer, respectively; the process includes: turning on the auxiliary heating to preheat the furnace tube and starting the vacuum process, pre-depositing the silicon nitride layer, depositing the silicon nitride layer, depositing the silicon oxynitride layer, and depositing the silicon oxide layer; Preferably, the deposited silicon nitride layer comprises: Si was deposited sequentially x N y 1 layer, deposited Si x N y 2 layers, deposited Si x N y 3 layers and 4 layers of deposited SixNy; During the four deposition processes, the flow rate of SiN4 gas introduced into the furnace tube decreased sequentially, while the flow rate of NH4 gas increased sequentially, and the deposition time increased sequentially.

[0011] Preferably, the deposited silicon nitride layer comprises: Deposited Si x N y Layer 1: SiN4 gas flow rate of 2930 sccm / min and NH4 gas flow rate of 10450 sccm / min are introduced into the furnace tube. At the same time, the pressure inside the furnace tube is controlled to reach 210 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply. The deposition time is 100 seconds. Deposited Si x N y 2nd layer: SiN4 gas flow rate of 2180 sccm / min and NH4 gas flow rate of 13570 sccm / min are introduced into the furnace tube, while the pressure inside the furnace tube is controlled to reach 213 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply, and the deposition time is 108 seconds. Deposited Si x N y3 layers: SiN4 gas flow rate of 1800 sccm / min and NH4 gas flow rate of 15617 sccm / min are introduced into the furnace tube. At the same time, the pressure inside the furnace tube is controlled to reach 213 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply, and the deposition time is 144 seconds. Deposition of SixNy 4 layers: SiN4 gas flow rate of 1400 sccm / min and NH4 gas flow rate of 15617 sccm / min are introduced into the furnace tube. At the same time, the pressure inside the furnace tube is controlled to reach 213 Pa and kept constant. Glow discharge is performed on the silicon wafer inside the furnace tube through radio frequency power supply. The deposition time is 270 seconds.

[0012] Preferably, the deposited silicon oxynitride layer comprises: Deposited SiO x N y Layer 1: SiN4 gas flow rate of 1380 sccm / min, NH4 gas flow rate of 5980 sccm / min, and NO2 gas flow rate of 8510 sccm / min are introduced into the furnace tube. At the same time, the pressure inside the furnace tube is controlled to reach 190 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply, and the deposition time is 175 seconds. Deposited SiO x N y 2nd layer: SiN4 gas flow rate of 1035 sccm / min, NH4 gas flow rate of 4600 sccm / min, and NO2 gas flow rate of 10235 sccm / min are introduced into the furnace tube. At the same time, the pressure inside the furnace tube is controlled to reach 190 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply, and the deposition time is 215 seconds.

[0013] Preferably, the deposition of the silicon oxide layer includes: introducing SiN4 gas at a flow rate of 1035 sccm / min and NO2 gas at a flow rate of 13455 sccm / min into the furnace tube, while controlling the pressure inside the furnace tube to reach 175 Pa and keeping it constant, and performing glow discharge on the silicon wafer inside the furnace tube through an RF power supply for a deposition time of 90 seconds.

[0014] (III) Beneficial Effects This invention provides a graded multilayer antireflective film for PECVD process and its preparation method, which has the following advantages compared with the prior art: By employing a gradient design in the multilayer antireflective coating, the refractive index of each layer changes gradually. This allows light to smoothly transition between different layers when entering the solar cell, effectively reducing light reflection loss. It also avoids light reflection caused by abrupt changes in refractive index at the interfaces between different material layers, improving the antireflective effect, increasing light absorption, improving short-circuit current and open-circuit voltage, and ultimately enhancing photoelectric conversion efficiency. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a schematic diagram of a gradient multilayer antireflective film structure; Figure 2 This is a schematic diagram of a traditional multilayer antireflective film structure. Figure 3 This is a flowchart of a method for preparing a graded multilayer antireflective film. Figure 4 The EQE curve of the gradient multilayer antireflective film; Figure 5 The reflectance curve is for a gradient multilayer antireflective coating.

[0016] Among them, 1 is a silicon nitride layer, 2 is a silicon oxynitride layer, and 3 is a silicon oxide layer. Specific implementation methods To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. like Figure 1 The embodiment of the present invention provided a graded multilayer antireflective film for PECVD process, wherein the PECVD deposition component content at the film layer interface of the graded multilayer antireflective film is gradually changed. That is, the PECVD deposition component content between adjacent film layers transitions gradually.

[0017] Specifically, the gradual change in PECVD deposition composition at the membrane layer interface is as follows: between adjacent membrane layers, the PECVD deposition composition content decreases in one membrane layer and increases in the other membrane layer.

[0018] Specifically, it can be a double-layer membrane or a multi-layer membrane. Compared to Figure 2 The traditional multilayer antireflective coating structure shown employs a gradient design, with a gradual change in refractive index between each layer. This allows light to smoothly transition between different layers when entering the solar cell, effectively reducing light reflection loss. It also avoids light reflection caused by abrupt changes in refractive index at the interfaces between different material layers, improving the antireflection effect, increasing light absorption, improving short-circuit current and open-circuit voltage, and ultimately enhancing photoelectric conversion efficiency.

[0019] In one embodiment, the gradient multilayer antireflective film includes a silicon nitride layer 1, a silicon oxynitride layer 2, and a silicon oxide layer 3.

[0020] Specifically, at the interface between the silicon nitride layer and the silicon oxynitride layer, the silicon nitride content deposited by PECVD decreases, while the silicon oxynitride content deposited by PECVD increases. Similarly, at the interface between the silicon oxynitride layer and the silicon oxide layer, the silicon oxynitride content deposited by PECVD decreases, while the silicon oxide content deposited by PECVD increases, until the silicon oxide layer is completely deposited.

[0021] Furthermore, to better illustrate the embodiments of the present invention, the present invention also provides a method for preparing a graded multilayer antireflective film by PECVD process, wherein film layer one, film layer two and film layer three are deposited sequentially by PECVD method, including: turning on auxiliary heating to preheat the furnace tube and starting vacuuming, pre-depositing film layer one, depositing film layer one, depositing film layer two, depositing film layer three, and evacuating the residual gas in the furnace tube.

[0022] Specifically, such as Figure 1 and Figure 3 As shown, the first film layer, the second film layer, and the third film layer are silicon nitride layer 1, silicon oxynitride layer 2, and silicon oxide layer 3, respectively; the process includes: turning on the auxiliary heating to preheat the furnace tube and starting the vacuum process, pre-depositing the silicon nitride layer, depositing the silicon nitride layer, depositing the silicon oxynitride layer, and depositing the silicon oxide layer; that is, during the deposition process, the vacuuming and pre-deposition process steps between different film layers are eliminated, and the reaction is in a state of sufficient reaction gas throughout the entire reaction time, resulting in more uniform gas distribution, denser film layers, and better film quality, with better resistance to ultraviolet rays, high temperature and humidity, and anti-PID characteristics; In one embodiment, the deposited silicon nitride layer includes: SixNy 1 layer, SixNy 2 layer, SixNy 3 layer and SixNy 4 layer were deposited sequentially; During the four deposition processes, the flow rate of SiN4 gas introduced into the furnace tube decreased sequentially, while the flow rate of NH4 gas increased sequentially, and the deposition time increased sequentially.

[0023] Specifically, the four depositional processes are as follows: Deposited Si x N y Layer 1: SiN4 gas flow rate of 2930 sccm / min and NH4 gas flow rate of 10450 sccm / min are introduced into the furnace tube. At the same time, the pressure inside the furnace tube is controlled to reach 210 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply. The deposition time is 100 seconds. Deposited Si x N y2nd layer: SiN4 gas flow rate of 2180 sccm / min and NH4 gas flow rate of 13570 sccm / min are introduced into the furnace tube, while the pressure inside the furnace tube is controlled to reach 213 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply, and the deposition time is 108 seconds. Deposited Si x N y 3 layers: SiN4 gas flow rate of 1800 sccm / min and NH4 gas flow rate of 15617 sccm / min are introduced into the furnace tube. At the same time, the pressure inside the furnace tube is controlled to reach 213 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply, and the deposition time is 144 seconds. Deposition of SixNy 4 layers: SiN4 gas flow rate of 1400 sccm / min and NH4 gas flow rate of 15617 sccm / min are introduced into the furnace tube. At the same time, the pressure inside the furnace tube is controlled to reach 213 Pa and kept constant. Glow discharge is performed on the silicon wafer inside the furnace tube through radio frequency power supply. The deposition time is 270 seconds.

[0024] Specifically, the deposited silicon oxynitride layer includes: Deposited SiO x N y Layer 1: SiN4 gas flow rate of 1380 sccm / min, NH4 gas flow rate of 5980 sccm / min, and NO2 gas flow rate of 8510 sccm / min are introduced into the furnace tube. At the same time, the pressure inside the furnace tube is controlled to reach 190 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply, and the deposition time is 175 seconds. Deposited SiO x N y 2nd layer: SiN4 gas flow rate of 1035 sccm / min, NH4 gas flow rate of 4600 sccm / min, and NO2 gas flow rate of 10235 sccm / min are introduced into the furnace tube. At the same time, the pressure inside the furnace tube is controlled to reach 190 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply, and the deposition time is 215 seconds.

[0025] Specifically, the deposition of the silicon oxide layer includes: introducing SiN4 gas at a flow rate of 1035 sccm / min and NO2 gas at a flow rate of 13455 sccm / min into the furnace tube, while controlling the pressure inside the furnace tube to reach 175 Pa and keeping it constant, and performing glow discharge on the silicon wafer inside the furnace tube through an RF power supply for a deposition time of 90 seconds.

[0026] By precisely controlling parameters such as gas ratio, pressure, and temperature during the PECVD deposition process, a gradual change in film composition can be achieved, thereby optimizing the antireflection effect. This gradient multilayer antireflection film not only improves the photoelectric conversion efficiency of solar cells but also enhances the weather resistance and stability of the cells, extending their service life.

[0027] The aforementioned SixNy, SiOxNy, and SixOy stacked films are deposited in a single step, without vacuuming between silicon nitride and silicon oxynitride, and subsequently between silicon oxynitride and silicon oxide. This results in SixNy and SiOxNy, and SiOxNy and SixOy films with continuously varying impurity ratios. The films are deposited continuously without deposition breaks. By eliminating the vacuuming and pre-deposition steps between different film layers, the process time is shortened, production capacity is increased, gas consumption is reduced, NOx emissions are reduced, water treatment costs are lowered, and the overall resource utilization rate is improved, effectively controlling environmental impact.

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail.

[0029] Example 1: S1: The graphite boat containing silicon wafers is fed into the furnace tube by a paddle rod. After the paddle rod is withdrawn, the furnace door is closed. S2: Turn on the auxiliary heating to preheat and raise the temperature of the furnace tube; S3: Leak Detection: Check whether the furnace tube leakage rate meets the process requirements; S4: Vacuuming: After the leak test meets the process requirements, the residual gas in the furnace tube is evacuated. S5: Pre-deposited Si x N y Layer: After leak detection meets the process requirements, SiN4 gas is introduced into the furnace tube at a flow rate of 2930 sccm / min and NH4 gas at a flow rate of 10450 sccm / min. At the same time, the pressure inside the furnace tube is controlled to reach 210 Pa and kept constant. The pre-deposition time is 10 seconds. S6: Deposited Si x N y Layer 1: SiN4 gas flow rate of 2930 sccm / min and NH4 gas flow rate of 10450 sccm / min are introduced into the furnace tube. At the same time, the pressure inside the furnace tube is controlled to reach 210 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply. The deposition time is 100 seconds. S7: Deposited Si x N y2nd layer: SiN4 gas flow rate of 2180 sccm / min and NH4 gas flow rate of 13570 sccm / min are introduced into the furnace tube, while the pressure inside the furnace tube is controlled to reach 213 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply, and the deposition time is 108 seconds. S8: Deposited Si x N y 3 layers: SiN4 gas flow rate of 1800 sccm / min and NH4 gas flow rate of 15617 sccm / min are introduced into the furnace tube. At the same time, the pressure inside the furnace tube is controlled to reach 213 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply, and the deposition time is 144 seconds. S9: Deposited Si x N y 4 layers: SiN4 gas flow rate of 1400 sccm / min and NH4 gas flow rate of 15617 sccm / min are introduced into the furnace tube. At the same time, the pressure inside the furnace tube is controlled to reach 213 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply, and the deposition time is 270 seconds. S10: Deposited SiO x N y Layer 1: SiN4 gas flow rate of 1380 sccm / min, NH4 gas flow rate of 5980 sccm / min, and NO2 gas flow rate of 8510 sccm / min are introduced into the furnace tube. At the same time, the pressure inside the furnace tube is controlled to reach 190 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply, and the deposition time is 175 seconds. S11: Deposited SiO x N y 2nd layer: SiN4 gas flow rate of 1035 sccm / min, NH4 gas flow rate of 4600 sccm / min, and NO2 gas flow rate of 10235 sccm / min are introduced into the furnace tube. At the same time, the pressure inside the furnace tube is controlled to reach 190 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply, and the deposition time is 215 seconds. S12: Deposited Si x O y Layer: SiN4 gas flow rate of 1035 sccm / min and NO2 gas flow rate of 13455 sccm / min are introduced into the furnace tube. At the same time, the pressure inside the furnace tube is controlled to reach 175 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply, and the deposition time is 90 seconds. S16: Vacuuming: Evacuate the residual gas inside the furnace tube; S17: Purge the furnace tubes with nitrogen; S18: After purging, the furnace tube is evacuated; S19: Nitrogen is added to restore the pressure inside the furnace tube to normal atmospheric pressure; S20: Furnace door, paddle rod removes graphite boat from the furnace tube.

[0030] Comparative Example 1: S1: The graphite boat containing silicon wafers is fed into the furnace tube by a paddle rod. After the paddle rod is withdrawn, the furnace door is closed. S2: Turn on the auxiliary heating to preheat and raise the temperature of the furnace tube; S3: Leak Detection: Check whether the furnace tube leakage rate meets the process requirements; S4: Vacuuming: After the leak test meets the process requirements, the residual gas in the furnace tube is evacuated. S5: Pre-deposited Si x N y Layer: SiN4 gas flow rate is 1300 sccm / min and NH4 gas flow rate is 5850 sccm / min, while the pressure inside the furnace tube is controlled to reach the set value and remain constant, and the pre-deposition time is 10 seconds; S6: Deposited Si x N y Layer 1: SiN4 gas flow rate of 2930 sccm / min and NH4 gas flow rate of 10450 sccm / min are introduced into the furnace tube. At the same time, the pressure inside the furnace tube is controlled to reach 210 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply. The deposition time is 100 seconds. S7: Deposited Si x N y 2nd layer: SiN4 gas flow rate of 2180 sccm / min and NH4 gas flow rate of 13570 sccm / min are introduced into the furnace tube, while the pressure inside the furnace tube is controlled to reach 213 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply, and the deposition time is 108 seconds. S8: Deposited Si x N y 3 layers: SiN4 gas flow rate of 1800 sccm / min and NH4 gas flow rate of 15617 sccm / min are introduced into the furnace tube. At the same time, the pressure inside the furnace tube is controlled to reach 213 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply, and the deposition time is 144 seconds. S9: Deposition of SixNy 4 layers: SiN4 gas flow rate of 1400 sccm / min and NH4 gas flow rate of 15617 sccm / min are introduced into the furnace tube, while the pressure inside the furnace tube is controlled to reach 213 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply, and the deposition time is 270 seconds. S10: Vacuuming: Evacuate the residual gas inside the furnace tube; S11: Pre-deposition of SiOxNy layer: SiN4 gas flow rate of 1380 sccm / min, NH4 gas flow rate of 5980 sccm / min, and NO2 gas flow rate of 8510 sccm / min are introduced into the furnace tube, while the pressure inside the furnace tube is controlled to reach 170 Pa and kept constant, and the pre-deposition time is 10 seconds; S12: Deposition of SiOxNy 1 layer: SiN4 gas flow rate of 1380 sccm / min, NH4 gas flow rate of 5980 sccm / min, and NO2 gas flow rate of 8510 sccm / min are introduced into the furnace tube. At the same time, the pressure inside the furnace tube is controlled to reach 170 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply. The deposition time is 175 seconds. S13: Deposition of 2 SiOxNy layers: SiN4 gas flow rate of 1035 sccm / min, NH4 gas flow rate of 4600 sccm / min, and NO2 gas flow rate of 10235 sccm / min are introduced into the furnace tube, while the pressure inside the furnace tube is controlled to reach 170 Pa and kept constant. Glow discharge is performed on the silicon wafer inside the furnace tube through the radio frequency power supply, and the deposition time is 215 seconds. S14: Vacuuming: Evacuate the residual gas inside the furnace tube; S15: Pre-deposition of SixOy layer: SiN4 gas flow rate of 1035 sccm / min and NO2 gas flow rate of 13455 sccm / min are introduced into the furnace tube, while the pressure inside the furnace tube is controlled to reach 160 Pa and kept constant, and the pre-deposition time is 10 seconds; S16: Deposition of SixOy layer: SiN4 gas flow rate of 1035 sccm / min and NO2 gas flow rate of 13455 sccm / min are introduced into the furnace tube, while the pressure inside the furnace tube is controlled to reach 160 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply, and the deposition time is 90 seconds. S17: Vacuuming: Evacuate the residual gas inside the furnace tube; S18: Purge the furnace tubes with nitrogen gas; S19: After purging, the furnace tube is evacuated; S20: Nitrogen purging to restore the pressure inside the furnace tube to normal atmospheric pressure; S21: Open the furnace door and use the paddle to remove the graphite boat from the furnace tube.

[0031] The electrical performance data of the graded multilayer antireflective film in the example and the comparative example were tested according to the national standard GB / T 6495.1 for electrical performance and efficiency. The results are compared as follows: Table 1 Comparison of Electrical Performance Parameters By comparing the above electrical performance data, it can be seen that the embodiment has better electrical performance data. The embodiment of the present invention, through a gradient design of the film structure and a gradual change in refractive index between each film layer, reduces the refractive index of the multilayer antireflective film, thereby further reducing the reflectivity of the stacked film and improving the battery conversion efficiency. Based on Figure 4 and Figure 5 It is known that the long-wavelength spectral response of the graded multilayer antireflection film is significantly better than that of the traditional multilayer antireflection film; the reflectivity of the graded multilayer antireflection film in the 300~365nm band is lower than that of the traditional multilayer antireflection film. Table 2 Comparison of PID96 Attenuation The attenuation of the graded multilayer antireflective film PID96 was qualified, and the attenuation value was 55% lower than that of the control group; Table 3 Gas Consumption Data Table 4 Gas Consumption Data The process time of this invention can be shortened by 50 seconds, the production capacity can be increased by 2%, the SiH4 consumption can be reduced by 1.36%, the NH3 consumption can be reduced by 0.54%, and the N2O consumption can be reduced by 4.29% (simultaneously achieving NOx compound emission reduction, water treatment cost reduction and the improvement of resource utilization rate of the whole chain, and the environmental load is effectively controlled). By preparing a SixNy / SiOxNy / SixOy graded stacked membrane, the vacuuming and pre-deposition processes between different membrane layers are eliminated, shortening the process time, increasing production capacity, and reducing gas consumption. This achieves NOx emission reduction, lower water treatment costs, and improved resource utilization across the entire chain, effectively controlling environmental impact. The graded membrane structure design, with its gradient refractive index gradient between layers, avoids light reflection caused by abrupt refractive index changes at the interfaces of different materials, improving anti-reflection effects, increasing light absorption, improving short-circuit current and open-circuit voltage, and enhancing photoelectric conversion efficiency. Eliminating the vacuuming and pre-deposition processes ensures a sufficient supply of reaction gas throughout the reaction time, resulting in more uniform gas distribution, denser membranes, and superior membrane quality with better UV resistance, high temperature and humidity resistance, and PID resistance. This invention only involves changes to the process formulation, without altering equipment or external power conditions, and is fully compatible with existing production lines, incurring no additional modification costs.

[0032] It should be noted that, in this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0033] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. 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 of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A graded multilayer antireflective film produced by PECVD process, characterized in that, The PECVD deposition composition at the junction of the gradient stacked antireflective film is gradually varied.

2. The PECVD process graded multilayer antireflective film according to claim 1, characterized in that, The gradual change in PECVD deposition composition at the membrane layer interface is as follows: between adjacent membrane layers, the PECVD deposition composition content decreases in one membrane layer and increases in the other membrane layer.

3. The PECVD process graded multilayer antireflective film according to claim 1, characterized in that, The gradient multilayer antireflective film includes a silicon nitride layer, a silicon oxynitride layer, and a silicon oxide layer.

4. The PECVD process graded multilayer antireflective film according to claim 3, characterized in that, At the junction of the silicon nitride layer and the silicon oxynitride layer, the silicon nitride content deposited by PECVD decreases, while the silicon oxynitride content deposited by PECVD increases; at the junction of the silicon oxynitride layer and the silicon oxide layer, the silicon oxynitride content deposited by PECVD decreases, while the silicon oxide content deposited by PECVD increases.

5. A method for preparing a graded multilayer antireflective film using PECVD process, characterized in that, The process involves sequentially depositing film layer one, film layer two, and film layer three using the PECVD method, including: preheating the furnace tube by activating auxiliary heating and starting vacuuming, pre-depositing film layer one, depositing film layer one, depositing film layer two, depositing film layer three, and evacuating the residual gas inside the furnace tube.

6. The method for preparing a graded multilayer antireflective film using PECVD process according to claim 5, characterized in that, The first film layer, the second film layer, and the third film layer are respectively a silicon nitride layer, a silicon oxynitride layer, and a silicon oxide layer; the process includes: turning on the auxiliary heating to preheat the furnace tube and starting the vacuum process, pre-depositing the silicon nitride layer, depositing the silicon nitride layer, depositing the silicon oxynitride layer, and depositing the silicon oxide layer.

7. The method for preparing a graded multilayer antireflective film using PECVD process according to claim 6, characterized in that, The deposited silicon nitride layer includes: Si was deposited sequentially x N y 1 layer, deposited Si x N y 2 layers, deposited Si x N y 3 layers and 4 layers of deposited SixNy; During the four deposition processes, the flow rate of SiN4 gas introduced into the furnace tube decreased sequentially, the flow rate of NH4 gas increased sequentially, and the deposition time increased sequentially.

8. The method for preparing a graded multilayer antireflective film using PECVD process according to claim 7, characterized in that, The deposited silicon nitride layer includes: Deposited Si x N y Layer 1: SiN4 gas flow rate of 2930 sccm / min and NH4 gas flow rate of 10450 sccm / min are introduced into the furnace tube. At the same time, the pressure inside the furnace tube is controlled to reach 210 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply for 100 seconds. Deposited Si x N y 2nd layer: SiN4 gas flow rate of 2180 sccm / min and NH4 gas flow rate of 13570 sccm / min are introduced into the furnace tube. At the same time, the pressure inside the furnace tube is controlled to reach 213 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply, and the deposition time is 108 seconds. Deposited Si x N y 3 layers: SiN4 gas flow rate of 1800 sccm / min and NH4 gas flow rate of 15617 sccm / min are introduced into the furnace tube. At the same time, the pressure inside the furnace tube is controlled to reach 213 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply, and the deposition time is 144 seconds. Deposition of SixNy 4 layers: SiN4 gas flow rate of 1400 sccm / min and NH4 gas flow rate of 15617 sccm / min are introduced into the furnace tube. At the same time, the pressure inside the furnace tube is controlled to reach 213 Pa and kept constant. Glow discharge is performed on the silicon wafer inside the furnace tube through radio frequency power supply. The deposition time is 270 seconds.

9. The method for preparing a graded multilayer antireflective film using PECVD process according to claim 6, characterized in that, The deposited silicon oxynitride layer includes: Deposited SiO x N y Layer 1: SiN4 gas flow rate of 1380 sccm / min, NH4 gas flow rate of 5980 sccm / min, and NO2 gas flow rate of 8510 sccm / min are introduced into the furnace tube. At the same time, the pressure inside the furnace tube is controlled to reach 190 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply, and the deposition time is 175 seconds. Deposited SiO x N y 2nd layer: SiN4 gas flow rate of 1035 sccm / min, NH4 gas flow rate of 4600 sccm / min, and NO2 gas flow rate of 10235 sccm / min are introduced into the furnace tube. At the same time, the pressure inside the furnace tube is controlled to reach 190 Pa and kept constant. The silicon wafer inside the furnace tube is subjected to glow discharge through radio frequency power supply, and the deposition time is 215 seconds.

10. The method for preparing a graded multilayer antireflective film using PECVD process according to claim 6, characterized in that, The deposition of the silicon oxide layer includes: introducing SiN4 gas at a flow rate of 1035 sccm / min and NO2 gas at a flow rate of 13455 sccm / min into the furnace tube, while controlling the pressure inside the furnace tube to reach 175 Pa and keeping it constant, and performing glow discharge on the silicon wafer inside the furnace tube through an RF power supply for a deposition time of 90 seconds.

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