Silicon solar battery antireflective thin film

Abstract

This invention discloses an anti-reflection film of silicon solar cell used in solar cells by depositing a rich silicon SiN film on the positive surface of a silicon chip and a SiN film with ideal match on the rich silicon SiN film, in which, and the film content closing to the Si chip surface is high and the surface pasivation effect is better than the SiN film approaching to the idea match, the surface composition speed is more than one time less than the normal matched SiN film, and the rich Si film is thin and only absorbs 20%-30% short waves with the wavelength about 300nm and does not absorb long-middle lightwaves and other composition approaches to ideal chemical match.

Description

technical field [0001] The invention relates to a silicon nitride anti-reflection film used for solar cells. Background technique [0002] Silicon nitride anti-reflection films are widely used in crystalline silicon (including single crystal silicon and polycrystalline silicon) solar cells. Usually, silicon nitride is prepared by plasma enhanced chemical vapor deposition (PECVD) or sputtering, of which PECVD is the most widely used. During PECVD deposition, silicon nitride films also contain hydrogen as a by-product of the reaction. Silicon nitride thin film mainly has the following functions in crystalline silicon solar cells: [0003] 1) Anti-reflection effect. Generally, the refractive index of silicon nitride is 1.9 to 2.3. Using a silicon nitride film with a suitable refractive index and thickness can greatly reduce the reflection of light by the solar cell, thereby improving the photoelectric conversion rate of the solar cell. [0004] 2) Surface passivation. The s...

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Problems solved by technology

Although this kind of film has almost no light absorption loss, the surface passivation performance is lacking (the surface recombination speed is more than twice that of silicon-rich silicon nitride film), and the refractive index is not ideal.