ESR characters of intrinsic defects in epitaxial semi-insulating 4H-SiC illuminated by Xe light

Abstract

The intrinsic defects in epitaxial semi-insulating 4H-SiC prepared by low pressure chemical vapor deposition (LPCVD) are studied by electron spin resonance (ESR) with different illumination times. The results show that the intrinsic defects in as-grown 4H-SiC consist of carbon vacancy (VC) and complex-compounds-related VC. There are two other apexes presented in the ESR spectra after illumination by Xe light, which are likely to be VSi and VCCSi. Illumination time changes the relative density of intrinsic defects in 4H-SiC; the relative density of intrinsic defects reaches a maximum when the illumination time is 2.5 min, and the ratio of VC to complex compounds is minimized simultaneously. It can be deduced that some VSi may be transformed to the complex-compounds-related VC because of the illumination.