towards the morphology control of stain etched porous silicon

Porous silicon films, nearly 100 nm thick, were produced by stain etching of n(+)-type silicon substrates. The films were studied by a non-destructive technique: dielectric function profiles were deduced by spectral reflectance via a finite difference model, and porosity was computed by the Effective Medium Approximation. The obtained information, combined with High Resolution Electron Microscopy observations, provided a deeper insight on the relations among technological process, morphology and reflective properties. Our preliminary results outline the possibility to control the porosity profile as well the reflectance of the porous films via the oxidising species concentration in the stain etching solution.