In this work capacitance-voltage measurements of three different dielectric layers, thermal silicon oxide, plasma enhanced chemical vapor deposited (PECVD) silicon oxide, and PECVD silicon nitride, on p-type silicon have been performed in order to obtain characteristics as the energy distribution of the interface trap density and the density of fixed charges. Spatially resolved capacitance-voltage, ellipsometry and lifetime measurements revealed the homogeneity of layer and passivation properties and their interrelation. Additionally lifetime measurements were used to evaluate x-radiation induced defects emerged during electron beam evaporation for sample metallization. (C) 2011 Elsevier B.V. All rights reserved.