Noise Effect on Thin Film Characterization Using Rotating Polarizer Analyzer Ellipsometer

摘要

We present theoretically the characterization of 100 nm SiO_2 thin film using spectroscopic rotating polarizer analyzer ellipsometer in which the two elements are rotating synchronously in opposite directions with the same angular speed. The proposed sample consists of air (ambient)/SiO_2 (thin film)/Si (substrate). The ellipsometric parameters ψ and Δ are calculated when a clean signal is received by the detector and when a hypothetical noise is imposed on this signal. The film thickness and the optical constants of the film are calculated for the noisy signal in the spectrum range 200-800 nm. The results are compared with the proposed thickness and with the published values for SiO_2 optical constants.