Deep levels in 6H-SiC wafers and step-controlled epitaxial layers

We have investigated deep levels in 6H-SiC wafers grown by a modified Lely method and step-controlled epitaxial layers by transient capacitance methods. Several deep electron traps, of which concentrations were on the order of 1015 cm−3, located at 0.39–0.69 eV below the conduction band edge were observed in the 6H-SiC wafers. However, the epitaxial layers by step-controlled epitaxy had very few traps of which concentrations were below the detection limit (<1013 cm−3).