Creation of Low-Relief Texture for a Photovoltaic Cell

Abstract

A novel method is described to create low-relief texture at a light-facing surface or a back surface of a photovoltaic cell. The peak-to-valley height and average peak-to-peak distance of the textured surface is less than about 1 microns, for example less than about 0.8 micron, for example about 0.5 microns or less. In a completed photovoltaic device, average reflectance for light having wavelength between 375 and 1010 nm at a light-facing surface with this texture is 6 percent or less, for example about 5 percent or less, in some instances about 3.5 percent. This texture is produced by forming an optional oxide layer at the surface, lightly buffing the surface, and etching with a crystallographically selective etch. Excellent texture may be produced by etching for as little as twelve minutes or less. Very little silicon, for example about 0.3 mg/cm2 or less, is lost at the textured surface during this etch.

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