Compensation in epitaxial cubic SiC films

Abstract
Hall measurements on four n-type cubic SiC films epitaxially grown by chemical vapor deposition on (100) Si substrates are reported. Detailed analyses of the temperature-dependent carrier concentrations indicate that the samples are highly compensated (>90%), contrary to the assumption of no compensation made in previous studies of similarly prepared SiC films. Donor ionization energies ED are found to be less than one-half the values previously reported. The values for ED and the donor concentration ND, combined with results for small bulk platelets with nitrogen donors, suggest the relation ED(ND)=ED(0)−αN1/3D for cubic SiC. A curve fit gives α≂2.6×10−5 meV cm and ED(0)≂48 meV, which is the generally accepted value of ED(0) for nitrogen donors in cubic SiC.