Electrochemical macroporous texturization of multicrystalline silicon

摘要

The anodization of p-type silicon (Si) in mixtures of hydrofluoric acid (HF) with specific organic solvents leads to the formation of a macroporous layer, which is very efficient in lowering the reflectivity. Multicrystalline Si is composed of large grains on the order of square centimeters exhibiting various crystallographic orientations. In this paper we present an electrochemical treatment that texturizes all the grains with microstructures in the micrometer range. The electrochemical treatment has the advantage over a chemical etching treatment in that the reaction can be controlled by the applied current density and that the results are easily reproduced. We found that the macroporous texturization is sensitive to various parameters, in particular the Si resistivity and crystallographic orientation. This efficient texturization method removes less than 3 -5 mu m of surface silicon, allowing its application for both Si wafer solar cells and thin film Si solar cells.