Infrared analysis of SiO, films grown on the 6H-SiC surfaces

Attenuated total reflection (ATR) spectra from thermally grown SiO, films on 6H polytype silicon carbide (6H-Sic) were investigated. The Si-0-Si stretching vibration of the longitudinal optical (LO) mode was observed in a band around 1250 cm-‘, and that of the transverse optical (TO) mode was observed in a band around 1074 cm-’ from the SiO, film (12 nm) on 6H-Sic, and the respective spectra agreed reasonably with the relative changes of reflectance calculated from a Ge/SiO,/SiC system using optical constants of amorphous SiO, and hexagonal Sic. ATR spectra show large difference in SiO, growth rate between the (OOOi)C-face and (OOOl)Si-face of 6H-SiC in a SiO, thickness range from 1 to 70 nm. Furthermore, decrease of the peak frequency of the TO mode was observed at SiO, thicknesses below 10 nm.