A solar cell passivation anti-reflection film and a coating process thereof

Abstract

A solar cell passivation antireflection film the anti-reflection film is formed by superposing and combining four silicon nitride films, the silicon nitride film comprises a film layer1, a film layer2, a film layer 3 and a film layer 4 from the inside to the outside, the film layer 1 to the film layer 3 are uniform refractive index film layers, the film layer 4 is a refractive index gradually changed film layer, the gradual changing direction of the film layer 4 is gradually reduced from the inside to the outside. By controlling flow change rate of the ammonia gas and the silane of the film layer 4, the gradually changed film layer is manufactured. At that outermost lay of the antireflection film, a graded-index film layer is arranged, As that incident light enters the film layer and directly contacts the gradually changed film layer, the refraction gradient of the incident light entering the cell sheet is reduced, the light loss caused by the large-angle refraction of the incident light entering the SiNx film is improved, the interface defects between different dielectric layers are overcome, and the absorption of short-wave light is enhanced.

Description

technical field [0001] The invention relates to a solar cell passivation anti-reflection film and a coating process thereof, belonging to the field of solar cell preparation. Background technique [0002] At present, in the production and preparation of solar cells, the conventional PECVD coating process is a two-layer film, three-layer film or multi-layer film coating process, which is to deposit three layers of silicon nitride film layers with gradually decreasing refractive index on the surface of the solar cell. The gases used are silane and ammonia. This film layer structure strengthens the surface passivation of the battery to a certain extent, reduces the recombination speed of minority carriers, and enhances the absorption of light after multiple refractions, which has an effect of improving efficiency. With the gradual optimization of crystalline silicon cell technology, especially the gradual increase in diffusion resistance, the conventional two-layer or three-lay...

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Problems solved by technology

[0002] At present, in the production and preparation of solar cells, the conventional PECVD coating process is a two-layer film, three-layer film or multi-layer film coating process, which is to deposit three layers of silicon nitride film layers with gradually decreasing refractive index on the surface of the solar cell. The gases used are silane and ammonia. This film layer structure strengthens the surface passivation of the battery to a certain extent, reduces the recombination speed of minority carriers, and enhances the absorption of light after multiple refractions, which has an effect of improving efficiency. With the gradual optimization of crystalline silicon cell technology, especially the gradual increase in diffusion resistance, the conventional two-layer or three-layer coating process can no longer meet the requirements for surface passivation and bulk passivation of crystalline silicon cells. The refractive index of each film layer is a certain value, so that there are relatively high interface defects between the film layers, and there is a large room for optimization

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