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, and optical absorption. A single acceptor level located between 0.27 and 0.35 eV above the valence band is associated with boron on a silicon lattice site. The deep nature of this acceptor level prevents complete thermal activation of the level at room temperature and thus carrier concentration measurements at this temperature will not give the total 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.