Temperature dependence of Raman scattering from 4H-SiC with hexagonal defects

Noncontact temperature measurements based on Raman scattering were performed on 4H-SiC with hexagonal defects. These measurements show that the four-phonon process makes a greater contribution to the E2(TO) mode than to the E1(TO) mode. The longer lifetimes of E2(TO) and E1(TO) phonons in hexagonal defects demonstrate that there are fewer possible decay channels than in the defect free zone. The absence of electronic Raman peaks in the hexagonal defects suggests that hexagonal defects seriously limit the uniformity of the nitrogen distribution. The intensity of electronic Raman spectra is related to the density of neutral nitrogen atoms.