Ellipsometry of anisotropic (sub)nanometric dielectric films on absorbing materials

Abstract

A new ellipsometric method was developed for determining optical parameters of ultrathin uniaxially anisotropic dielectric films. It is based on the phase conversion measurements of polarized reflected light at different incident angles. The elaborated technique possesses very high sensitivity and is successfully applicable even for sub-nanometric layers because the phase changes for such layers on absorbing substrates are generally markedly greater than the measurement error. Another interesting facet of this method lies in the fact that the traditional model-based regression analysis is not used for data handling. The inversion problem is resolved on the basis of an original analytical approach, which has no need of initial guesses for the desired parameters. The presented method is tested using a numerical simulation.

Keywords:

• ultrathin dielectric layer
• anisotropic film
• ellipsometry
• optical diagnostics

Acknowledgments

This research was supported by Estonian Research Council (Project IUT2-24) and Estonian Centre of Excellence in Research (Project TK117).