SPECTROSCOPIC ELLIPSOMETRY OF SLIGHTLY INHOMOGENEOUS NONABSORBING THIN-FILMS WITH ARBITRARY REFRACTIVE-INDEX PROFILES - THEORETICAL-STUDY

We develop a new approximation for the amplitude reflection coefficien ts of a slightly inhomogeneous thin film. This approximation incorpora tes exactly the interference effects at the substrate and the ambient interfaces. Interference effects inside the inhomogeneous film are inc orporated in the Born approximation. We also develop a new approach to the reconstruction of the refractive-index profile from ellipsometric spectra. It is based on a physically sound parameterization of the re fractive-index profile. The new approach is tested on the model recons truction problem. (C) 1998 Optical Society of America.