Multilayer passivation film of crystalline-silicon battery and manufacturing method thereof

Abstract

The invention discloses a multilayer passivation film of a crystalline-silicon battery and a manufacturing method thereof. The multilayer passivation film comprises a first silicon oxide film, a silicon nitride film, a second silicon oxide film and a silicon oxynitride film. The silicon nitride film is deposited on the first silicon oxide film; the second silicon oxide film is deposited on the silicon nitride film; and the silicon oxynitride film is deposited on the second silicon oxide film. The thickness of the first silicon oxide film is 5 to 9 nm, the thickness of the silicon nitride film is 60 to 90 nm, the thickness of the second silicon oxide film is 10 to 20nm, and the thickness of the silicon oxynitride film is 15 to 30nm. According to the invention, the probability of total reflection of light is improved substantially and thus more light enters a silicon wafer to generate more carriers, so that the battery efficiency is enhanced.

Description

technical field [0001] The invention relates to the technical field of solar cells, in particular to a multilayer passivation film for crystalline silicon cells and a manufacturing method thereof. Background technique [0002] At present, in the mass production of solar cells, anti-reflection coatings are often deposited on the surface of silicon wafers to increase light utilization and improve cell conversion efficiency. Common thin films mainly include silicon nitride SiNx and silicon oxide SiOx, and the two thin films have different characteristics and preparation methods. Silicon nitride SiNx films are mostly prepared by PECVD deposition, which has the characteristics of good anti-reflection performance, good bulk passivation effect, low deposition temperature, and high productivity, but the high bonding interface state and extinction characteristics of silicon nitride film and silicon substrate are also limited. The further improvement of the battery conversion efficie...

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Problems solved by technology

Silicon nitride SiNx films are mostly prepared by PECVD deposition, which has the characteristics of good anti-reflection performance, good bulk passivation effect, low deposition temperature, and high productivity, but the high interface state and extinction characteristics of the silicon nitride film and the silicon substrate are also limited. The further improvement of the battery conversion efficiency

Compared with SiNx, silicon oxide SiOx film has a lower interface state and lower refractive index, which can provide a good surface passivation effect, but its preparation method is mostly grown by high-temperature thermal oxidation method, which causes great damage to the silicon wafer , and the process is complex and costly, which is not conducive to mass production

[0003] In addition, the anti-PID characteristics of conventional solar cells are improved by increasing the refractive index of the SiNx film. This method will bring a certain degree of efficiency loss, but depositing a SiOx film on the bottom layer will not lead to a decrease in efficiency while improving the anti-PID characteristics.

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