Ellipsometric Technique for Obtaining Substrate Optical Constants

Abstract

A method for determining substrate optical constants, surface film thickness, and surface film optical constants has been devised by measuring the ellipsometer angles Δ and ψ at several angles of incidence. This method, previously reported as impossible, solves in a simple fashion the ellipsometry equations for one consistent values of surface film thickness in association with compatible values of substrate optical constants. The technique is advantageous in that vacuum ellipsometry is eliminated and previously unmeasured materials such as alloy structures may be studied readily. Data on aluminum, molybdenum, and silicon are presented illustrating the technique.