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 SiO _2 /Si system at temperatures varying from 25 to 600 °C. By using Cauchy dispersion model to describe SiO _2 layer and B-spline to parameterize Si substrate, the temperature dependent optical constants of SiO _2 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 SiO _2 at elevated temperature was obtained by ellipsometry. The results indicate that the temperature coefficient increases with increasing wavelength and decreasing temperature.

Keywords

• SiO2
• optical constants
• temperature
• refractive index
• ellipsometry