CHARACTERIZATION OF POROUS SILICON LAYERS BY SPECTROSCOPIC ELLIPSOMETRY

The influence of the microscopic structure of porous silicon layers on the dielectric function is determined by spectroscopic ellipsometry. The investigated layers were formed on high and low p-type doped subst rates. Their microscopic structure was changed by varying the current density in the electrochemical formation process. The measured dielect ric function was found to be extremely sensitive on the microscopic st ructure. New features occur in the measured dielectric function which are characteristic for the silicon skeleton in the porous silicon laye rs.