Diamond and β-SiC heteroepitaxial interfaces: A theoretical and experimental study

A comparative study of both theoretical and experimental aspects of the diamond/\ensuremath{\beta}-SiC heteroepitaxial interface was performed. The theoretical modeling was conducted to examine the various combinations of like and unlike interfacial planes between diamond and \ensuremath{\beta}-SiC based on a geometric criterion formulated in reciprocal space for minimization of interfacial misfit and strain energies. The modeling results indicated that the low-index unlike pair between diamond {114} and \ensuremath{\beta}-SiC {221} has the greatest potential for minimizing the interfacial energy and is, therefore, strongly recommended for experimental investigations. The low-index-like pairs between diamond and \ensuremath{\beta}-SiC are next in potential, and diamond (001)/\ensuremath{\beta}-SiC(001) heteroepitaxy has been confirmed via experimental observations. Other configurations yield high interfacial energies and are unlikely to occur. The relatively high strain energy associated with the like-pair heteroepitaxy can be relieved by the introduction of misfit dislocations at the interface. These misfit dislocations have also been experimentally observed by cross-sectional transmission electron microscopy. The calculated misfit dislocation densities correlate well with the experimental measurements. The misfit dislocations observed in diamond not only accommodate the misfit strain but also cause both interfacial tilting and azimuthal rotational misorientations.