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Indexed by:期刊论文

Date of Publication:2022-06-29

Journal:人工晶体学报

Affiliation of Author(s):材料科学与工程学院

Issue:11

Page Number:2364-2368,2379

ISSN No.:1000-985X

Abstract:Porous silicon gettering is an effective way to reduce impurities and defects in crystalline silicon to improve the conversion efficiency of solar cells. In this paper, porous silicon was prepared on monocrystalline silicon wafers by electrochemical etching method. The impact of the different electrochemical etching time for the preparation of porous silicon gettering effect was studied and mechanism of the porous silicon gettering was analyzed by observing the morphology, porosity of the porous silicon, the thickness of the porous layer and the resistivity change of monocrystalline silicon wafers. The results showed that the resistivity of silicon wafers are improved with etching time of 30 min, 40 min, 50 min and 60 min under the current density of 100 mA/cm2 after gettering treatment and with the etching time increasing, the resistivity increases which coincides with the result of morphology and porosity as well as the thickness of the porous silicon layer. The elastic mechanical stress is formed along with the formation of the porous silicon, and the stress and lattice constant increases with increasing the etching time, which promotes the migration and enrichment of the defects and metal impurities at the interface of the silicon substrate and porous silicon layer thus leading to the increasing of resistivity in monocrystalline silicon after gettering.

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