Ellipsometric determination of the thickness and the refractive index of superficial films deposited on metal mirrors

Ellipsometry is an optical method that allows very accurate determination of the optical constants of surfaces or determination of the thickness and optical constants of superficial films on solid substrates. If the determination of the optical characteristics of transparent superficial films is relatively simple, at least two ellipsometric measurements are required for optically absorbent films: at two different angles of incidence or using two different incidence media. This involves additional problems with errors related to the realignment of the ellipsometer. Ways to obtain the thicknesses and optical constants for thin or thick transparent or non-transparent superficial films are presented. A simple graphical method is presented to determine the thicknesses and optical constants of thin absorbent films with non- uniform thickness.