Method for preparing double acid etching textures on polycrystalline silicon surface

Abstract

The invention discloses a method for preparing double acid etching textures on a polycrystalline silicon surface. Different from the previous process, the method can solve the problem of non-uniformity of silicon slice etching pits, further solves the problem of color difference of a solar cell after PECVD (plasma enhanced chemical vapor deposition) coating, and optimizes the appearance of the solar cell. The first acid etching texture is characterized by low temperature and short time, a mechanical damage layer on the surface of a silicon slice is effectively removed by controlling the concentration of etching reaction liquid components, and small etching pits are formed. The second texture is characterized by high temperature and long time, and large and uniform etching pits are formed on the surface of the silicon slice. By the method, the shortcoming of non-uniformity of the etching pits in the traditional process is effectively overcome, the problem of color difference of the solar cell after PECVD coating is solved, and the production cost is not increased.

Description

technical field [0001] The invention relates to a production process of a polycrystalline silicon solar cell, belonging to the technical field of semiconductor photoelectric materials. Background technique [0002] In the acid etching surface texture process of solar cells, the acid etching solution is generally HF, HNO 3 It is mixed with deionized water in a certain proportion, among which HNO 3 As a strong oxidant, it provides the holes needed for the reaction in the reaction; the role of HF is to react with the intermediate product SiO 2 The reaction forms complex H 2 SiF 6 , to promote the reaction; deionized water buffers the reaction. In the reaction, the acid etching rate of silicon has nothing to do with the grain orientation, so the acid etching texture is also called isotropic etching. The corrosion reaction first occurs at the position with the lowest activation energy (for example, at crystal defects or surface damage), and the initial corrosion can be regar...

AI Technical Summary

Problems solved by technology

If the traditional corrosion solution is used, the amount of corrosion with high density of the damaged layer will be too large, and the appearance of the corrosion pit will be different, which will cause color difference of the solar cells after PECVD coating

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