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

Experimental results are reported for boron-doping of 6H and 4H silicon carbide epitaxial layers from a solid boron-nitride source. The purpose of these experiments is to demonstrate close compensation of the resulting CVD grown epitaxial layers by adjusting a single growth parameter, namely, the average ratio of silicon to carbon in the precursor gases during growth (i.e. site-competition epitaxy). Net doping concentrations from more than 1017 cm−3 n-type to more than 1017 cm−3 p-type are observed. Type conversion is principally correlated with the silicon-to-carbon ratio. The n-type compensating species is assumed to be nitrogen. At intermediate values of silicon-to-carbon ratio (typically between 0.11 and 0.2 for our particular conditions) close compensation is observed, and, possibly, semi-insulating behavior.