Ellipsometric data processing: an efficient method and an analysis of the relative errors.

A method is proposed for processing ellipsometric data, leading to strict decoupling of the system describing the optical response of a transparent film deposited on a thick opaque substrate. The method is very efficient and enables a thorough semianalytical discussion of the errors involved in the measurements. In particular, resonant errors as well as optimum incidence angles are systematically derived from the formalism.