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

Abstract
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 (13 cm−3).