On the morphology of stain-etched porous silicon films

Morphology of stain-etched porous silicon films was investigated by a non-destructive technique, based on reflectance spectrometry: dielectric function profiles were computed by spectral reflectance via a finite difference model, and porosity was deduced by the effective medium approximation. Theoretical calculations were supported by high-resolution electron microscopy observations. The relations among oxidising species concentration in the etching solution, porosity profile and surface reflectance of the films were investigated.