Temperature dependent optical constants for SiO2 film on Si substrate by ellipsometry

Abstract

In situ ellipsometry measurements in the spectra range from 246 to 1000 nm were performed on a SiO2/Si system at temperatures varying from 25 to 600 °C. By using Cauchy dispersion model to describe SiO2 layer and B-spline to parameterize Si substrate, the temperature dependent optical constants of SiO2 film and Si substrate were precisely determined and analyzed which is helpful to understand the temperature effect of substrate for ellipsometry measurement. The temperature coefficient of refractive index of SiO2 at elevated temperature was obtained by ellipsometry. The results indicate that the temperature coefficient increases with increasing wavelength and decreasing temperature.