ELECTRONIC-PROPERTIES OF BORON IN P-TYPE BULK 6H-SIC

The electronic properties of boron in bulk 6H-SiC have been studied by temperature dependent Hall effect, thermal admittance spectroscopy, a nd optical absorption. A single acceptor level located between 0.27 an d 0.35 eV above the valence band is associated with boron on a silicon lattice site. The deep nature of this acceptor level prevents complet e thermal activation of the level at room temperature and thus carrier concentration measurements at this temperature will not give the tota l boron concentration. A spread in the measured activation energy for boron is reported. Measurement of optical absorption is suggested as a nondestructive measure of boron concentration. No evidence for the D- center was observed in this material.