Characteristics of homoepitaxial 4H-SiC films grown on c-axis substrates offcut towards 〈11̄00〉 or 〈112̄0〉

Substrate orientation plays a critical role in determining SiC epilayer quality, but limited work has been done to examine the effect of offcut directions on 4H-SiC epilayers. 4H-SiC epilayers were grown on substrates offcut 8° towards either the 〈1100〉 or the 〈1120〉 crystalline direction. Epilayers up to 15.5 μm thick, possessing smooth morphologies free of large-scale step bunching, were grown on both substrate orientations. Triangular defects were observed primarily on the wafer periphery, and the triangular defect density depended only on offcut angle. Atomic force microscopy analysis confirmed smooth surfaces for epilayers up to 15.5 μm thick grown on 〈1100〉 offcut substrates. Low-energy electron diffraction analysis of epilayers grown on substrates offcut towards 〈1100〉 showed an ordered surface. Nitrogen and aluminum doping were successfully obtained for epilayers grown on substrates offcut towards 〈1100〉, and n-type and p-type doping control were demonstrated.