Dielectric function and reflectivity of 3C–silicon carbide and the component perpendicular to the c axis of 6H–silicon carbide in the energy region 1.5–9.5 eV

Abstract

The optical properties of commercially available 3C- and 6H-SiC single crystals were studied in the energy region 1.5–9.5 eV with conventional and synchrotron-radiation spectroscopic ellipsometry. The surface perfection of the materials was investigated by transmission electron and atomic force microscopies. The calculated values for the effective and static dielectric functions were higher than those found in the literature. This is consistent with the fine structure and absolute values of the corresponding reflectance spectra, which were higher than those reported in other studies. The dispersion of the refractive indices in the energy region below and above the indirect gap is determined and can be used as reference and for the design and analysis of semiconductor structures and devices.