Method for numerical inversion of the ellipsometry equation for transparent films

Abstract

A method for determining the refractive index and the thickness of surface transparent films from measured ellipsometric angles Ψ and Δ is described. This method is based on a complex bilinear transformation that maps one circle to another in the Gaussian plane. This method is compared with Reinberg’s method and with the Newton–Raphson approximation. High convergence is realized for thin-film evaluation without deteriorating thick-film evaluation.