ESR Study of Defects in Epitaxially Grown 3C-SiC

Abstract

Defect centers in as-grown and electron irradiated 3C-SiC epilayers were studied by electron spin resonance(ESR) at temperatures between 4.2K and 300K. An isotropic 3-line ESR spectrum (g=2.0049, A=1.1x10-4 cm-1) was observed only below 40K. Intensities of the center line and a pair of the side lines of the 3-line spectrum show different dependence on temperature and microwave power level, indicating that the 3-line spectrum consists of a hyperfine component and a broad single line component with approximately the same g-value. No significant change was observed in the 3-line spectrum by 1 MeV electron irradiation, though an isotropic ESR signal with g=2.0029 and two weak anisotropic ESR signals appeared at room temperature in irradiated specimens. The isotropic spectrum consists of five lines equally spaced at intervals of 1.5G. By annealing up to 800°C, three recovery stages (150°C, 350°C, and 750°C) were found and an activation energy of 2.2 eV was obtained for the 750°C stage.