OPTICALLY DETECTED MAGNETIC-RESONANCE STUDIES OF DEFECTS IN 3C SIC EPITAXIAL LAYERS

Optically detected magnetic resonance (ODMR) was used to study defects in 3C SiC epitaxial layers grown at high temperatures (1550 degrees C ) by chemical vapour deposition on a freestanding 3C SiC him substrate . An isotropic, very broad and asymmetric ODMR line was observed under ultraviolet light excitation. This line is shown to be due to the ove rlapping of two different isotropic spectra, as revealed by magnetic h eld modulation measurements. Both spectra can be described by an effec tive electron spin S=1/2. The higher held line with a g-value of 2.006 may be related to a silicon vacancy. Using below bandgap excitation, the lower field spectrum (g=2.012) was found to have a triplet structu re which could be due to the hyperfine of N-14. This defect is related to a new photoluminescence band in the region of 1.1-1.58 eV. (C) 199 7 Elsevier Science S.A.