Low-pressure oxidization process for crystalline silicon small-textured structure

Abstract

The invention discloses a low-pressure oxidization process for a crystalline silicon small-textured structure. The low-pressure oxidization process is carried out on a crystalline silicon wafer with the textured dimension of 0.1-2[mu]m to generate a layer of uniform SiO<2> layer on the surface of the crystalline silicon small-textured structure, so that the surface recombination rate is lowered, the minority carrier lifetime is prolonged, the problem of surface passivation of the crystalline silicon small-textured structure is solved, the surface doping concentration of an emitter can be lowered, the problem of overhigh surface doping concentration of the small-textured structure can be solved, the influence from "dead layer" can be weakened obviously, and the short-wave response of the battery can be improved; meanwhile, the oxidization process is performed in a low-pressure state, so that gas stability and uniformity and environment cleanliness in a diffusion furnace tube can be improved, the sheet resistance uniformity after oxidization is greatly improved and the battery efficiency is improved; and meanwhile, the problem of abnormal appearance of the silicon wafer surface in normal-pressure oxidization can be solved, the number of the abnormal white spots and the like on the silicon wafer surface can be obviously reduced, and the battery product quality is improved effectively.

Description

technical field [0001] The invention relates to the field of crystalline silicon batteries, in particular to a crystalline silicon texturing process. Background technique [0002] High-efficiency, low-cost crystalline silicon cells are the mainstream direction of the photovoltaic market in the future, and how to avoid optical and electrical losses as much as possible are two core issues of research concern. [0003] Light trapping technology is an important means to solve optical loss and improve the utilization rate of solar spectrum. In order to improve the light trapping effect on the surface of crystalline silicon cells and enhance the absorption of light, small textured structures are increasingly used in crystalline silicon cells. However, since the size of the textured surface decreases from the micron level to the quasi-micron level, it has a great impact on the solar cell diffusion process and the anti-reflection film deposition process, which is likely to cause pr...

AI Technical Summary

Problems solved by technology

However, since the size of the textured surface decreases from the micron level to the quasi-micron level, it has a great impact on the solar cell diffusion process and the anti-reflection film deposition process, which is likely to cause problems such as high doping concentration on the diffusion surface and poor passivation effect.

Some people try to solve this problem by adding a traditional thermal oxidation process before the anti-reflection film deposition process. However, the traditional thermal oxidation process will cause problems such as uneven resistance after oxidation, poor passivation effect, and easy to produce white spots and other poor appearance. Affect the appearance quality of the cell