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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 (V C ) and complex-compounds-related V C.There are two other apexes presented in the ESR spectra after illumination by Xe light,which are likely to be V Si and V C C Si.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 V C to complex compounds is minimized simultaneously.It can be deduced that some V Si may be transformed to the complex-compounds-related V C because of the illumination.
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 V C. Both are two other apexes presented in the ESR spectra after illumination by Xe light, which are likely to be V Si and VCC Si.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 V Si may be transformed to the complex- compounds-related VC because of the illumination.