Effect of noise on the optical parameters extracted from different ellipsometric configurations

Abstract

We compare different types of spectroscopic ellipsometric structures concerning the effect of noise on the optical parameters extracted from these systems. The comparison involves the rotating analyzer spectroscopic ellipsometer and the rotating polarizer and analyzer (RPA) spectroscopic ellipsometer in which the polarizer and the analyzer rotate with different speed ratios. All systems being compared are investigated for c-Si and GaAs samples for a noisy signal. The percentage error in the real and imaginary parts of the refractive index of the samples is calculated and plotted with photon energy in the range 15–3 eV. The results reveal that the RPA spectroscopic ellipsometer in which the polarizer and the analyzer rotate with a 1: 1 ratio corresponds to minimum error.