BORON ACCEPTOR LEVELS IN 6H-SIC BULK SAMPLES

Thermal admittance spectroscopy has been used to determine the ground- state energies of the boron impurity in 6H-SiC. The background doping, N-A-N-D, of the samples used in this study ranged from 3x10(16) to 1x 10(18) cm(-3). From electron spin resonance studies, it is known that boron substitutes for silicon in the silicon carbide lattice occupying three inequivalent sites. Using admittance spectroscopy the ground st ate energies of E-v+0.27 eV, E-v+0.31 eV, and E-v+0.38 eV were determi ned for the shallow boron acceptor in 6H-SiC. The free carrier concent ration does not appear to be the only determining factor for which the boron acceptor level is observed. (C) 1997 American Institute of Phys ics.