Abstract
This article describes growth and characterization of the highest quality reproducible 3C‐SiC heteroepitaxial films ever reported. By properly nucleating 3C‐SiC growth on top of perfectly on‐axis (0001) 4H‐SiC mesa surfaces completely free of atomic scale steps and extended defects, growth of 3C‐SiC mesa heterofilms completely free of extended crystal defects can be achieved. In contrast, nucleation and growth of 3C‐SiC mesa heterofilms on top of 4H‐SiC mesas with atomic‐scale steps always results in numerous observable dislocations threading through the 3C‐SiC epilayer. High‐resolution X‐ray diffraction (HRXRD) and high resolution cross‐sectional transmission electron microscopy (HRXTEM) measurements indicate non‐trivial, in‐plane, lattice mismatch between the 3C and 4H layers. This mismatch is somewhat relieved in the step‐free mesa case via misfit dislocations confined to the 3C/4H interfacial region without dislocations threading into the overlying 3C‐SiC layer. These results indicate that the presence or absence of steps at the 3C/4H heteroepitaxial interface critically impacts the quality, defect structure, and relaxation mechanisms of single‐crystal heteroepitaxial 3C‐SiC films.