Close compensation of 6H and 4H silicon carbide by silicon-to-carbon ratiocontrol

Experimental results are reported for boron-doping of 6H and 4H silicon car bide epitaxial layers from a solid boron-nitride source. The purpose of the se experiments is to demonstrate close compensation of the resulting CVD gr own epitaxial layers by adjusting a single growth parameter, namely, the av erage ratio of silicon to carbon in the precursor gases during growth (i.e. site-competition epitaxy). Net doping concentrations from more than 10(17) cm(-3) n-type to more than 10(17) cm(-3) p-type are observed. Type convers ion is principally correlated with the silicon-to-carbon ratio. The n-type compensating species is assumed to be nitrogen. At intermediate values of s ilicon-to-carbon ratio (typically between 0.11 and 0.2 for our particular c onditions) close compensation is observed, and, possibly, semi-insulating b ehavior. (C) 1999 Elsevier Science S.A. All rights reserved.