Ellipsometer measurement of thickness and optical properties of thin absorbing films

Solutions for the thickness (d) and optical properties (n and k) of absorbing films overlying substrates of known optical properties may be found using ellipsometry. Themethod presented here uses measurements obtained at different incidence angles. Simultaneous solutions for n, k and d are found using the “exact” Drude equations and iteration techniques implemented on a microcomputer. Examples for a number of films demonstrate correct solutions. The accuracy of solutions is dependent upon specimen configuration and measurement accuracy. Highly accurate solutions may be obtained for films of practical importance using existing ellipsometers. Accuracy of experimental solutions is determined a posteriori given the measurement inaccuracy.