Raman microprobe assessment of low-pressure chemical vapor deposition-grown 4H-SiC epilayers

Raman microprobe measurements have been made on several 4H-SiC epilayers grown by low-pressure chemical vapor deposition (LPCVD). The peak intensity of the TO phonon at 795.7 cm(-1) normalized by that of the TO phonon at 775.0 cm(-1) was found to vary with the growth conditions as well as localized microstructural disorder. The relative intensity of the LO peak at 961.6 cm(-1) was also affected by localized microstructural disorder. The dependence of the relative intensities of these two Raman scattering peaks on the morphology as well as the growth conditions provides important insight into the application of Raman scattering measurements to evaluating the quality of 4H-SiC epilayers.