The nitride layers were prepared by direct thermal nitridation of 6H-SiC substrates at 1200-1570 C in a NH 3 atmosphere. The layer was characterized by using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Raman scattering spectroscopy. The thickness of the nitride layers prepared at lower than 1400 C was estimated to be less than 10 nm. The higher nitridation temperature resulted in the formation of a thicker surface layer. XPS measurement showed that the surface layer was composed of N, Si, C and O. Peaks corresponding to -Si 3 N 4 were detected in the Raman spectra and the XRD patterns of the sample prepared at higher than 1500 C, indicating the crystallization of the nitrided layer.

Nitride layers were grown on a SiC surface by thermal nitridation using a mixed gas of NH 3 and N 2 . The thermal nitridation was carried out at 1000°C and 1090 °C under the atmospheric pressure. X-ray photoelectron spectroscopy (XPS) was used to characterize the surface layer. The peaks from Si2p, C1s, N1s and O1s were observed in the XPS spectra. These peaks showed that the surface layer consisted of Si, N, C and O. The thickness of the surface layer was estimated at less than 10 nm.