Raman Analysis of a Crystalline SiC Sample Prepared fromCarbon-Saturated Melt of Silicon

Crystalline SiC samples were prepared in solidification of silicon melt saturated by carbon solved from the inner wall of a graphite crucible. The Crystalline structure of the samples was analysed in Raman spectroscopy and confirmed as 3C-SiC both in x-ray diffraction and x-ray photoelectron spectroscopy(XPS). The Raman spectra of the samples present a strong sharp peak located at 796.3 cm^-1 with a full width at half maximum about 6 cm^-1 and three weak peaks broadened around 1525.6, 1631.4 and 1719.1 cm^-1, respectively. The former belongs to the transverse optical phonons of 3C-SiC, while the latter can be attributed to the second-order scattering. However, the longitudinal optical mode of 3C-SiC has not been found for our samples. An additional broadened peak at 532.2 cm^-1 may imply the existence of some lattice defect in the samples, which is related to nitrogen introduced unintentionally into the lattice in the growth process and confirmed in XPS of N 1s binding energy centered at 400.9 eV.