Optical Constants of 6H–SiC Single Crystals

Abstract

The complex dielectric functions of 6H–SiC for light polarized perpendicular and parallel to the optic axis c were measured using spectroscopic ellipsometry. The measurements were made on the (0001) and (011̄0) surfaces of 6H–SiC in the photon energy range between 1.2 and 5.4 eV at room temperature. The measured dielectric-function spectra were fitted with a classical Lorentz-type oscillator model. The indices of refraction in the transparent region (E < 4.5 eV) were also analyzed using the first-order Sellmeier equation. From this analysis, we obtained the high-frequency dielectric constants ε _∞ of 6H–SiC as 6.59 for E ⊥c and 6.67 for E //c. Using the Lyddane-Sachs-Teller relation, we also obtained the static dielectric constants ε _s as 9.76 for E ⊥c and 9.98 for E //c.