A study of V³⁺ and the Vanadium acceptor level in semi-insulating 6H-SiC

Abstract

Infrared absorption (IR) and electron paramagnetic resonance (EPR) spectroscopies are used to study the V 3+ impurity and the vanadium acceptor level in 6H semi-insulating SiC. IR and EPR data obtained from samples cut from the same wafer support the assignment of the 0.60 and 0.62 eV IR absorption lines to substitutional V 3+ . Photo-induced EPR measurements reveal identical photo-thresholds for V 3+ and V 4+ ions. A peak at 0.8 eV, where the intensity of the three plus charge state decreases and the four plus charge state increases by an equal amount, is thought to represent excitation of an electron from V 3+ to the conduction band edge. The 0.8 eV peak is therefore attributed to the V 3+/4+ level. The difference between the optically measured value reported here and that measured previously using temperature dependent techniques is attributed thermal relaxation.