Towards the morphology control of stain etched porous silicon

Porous silicon films, nearly 100 nm thick, were produced by stain etching o f n(+)-type silicon substrates. The films were studied by a non-destructive technique: dielectric function profiles were deduced by spectral reflectan ce via a finite difference model, and porosity was computed by the Effectiv e Medium Approximation. The obtained information, combined with High Resolu tion Electron Microscopy observations, provided a deeper insight on the rel ations among technological process, morphology and reflective properties. O ur preliminary results outline the possibility to control the porosity prof ile as well the reflectance of the porous films via the oxidising species c oncentration in the stain etching solution.