Heteroepitaxy of diamond on c-BN: Growth mechanisms and defect characterization

Diamond films grown on {100}, {111} boron-terminated, and nitrogen-terminated facets of cubic boron nitride (c-BN) single crystals were characterized by Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The evolution of morphology and microstructure of the diamond films at different stages during the growth process were followed by SEM investigation. The results indicate that diamond growth proceeds by nucleation of oriented three-dimensional islands followed by their coalescence. Cross-sectional TEM specimens were prepared from thick (over 10 μm) continuous diamond films grown on {111} boron-terminated surfaces. Selected-area diffraction and high resolution TEM images show that the diamond film has a parallel orientation relationship with respect to the substrate. Characteristic defects, common to diamond films obtained by chemical vapor deposition on other substrates, are also discussed.