Nucleation growth mechanism of diamond on 4H-SiC substrate by microwave plasma chemical vapor deposition

Diamond was deposited on mirror-like polished, grinded, and grooved 4H-SiC substrates by microwave plasma chemical vapor deposition. The nucleation process and grain morphology varied with different growth time and concentrations of methane in hydrogen were observed by scanning electron microscopy, X-ray diffraction and Raman spectroscopy. It was shown that the nucleation density increased by three orders of magnitude on the grinded substrate, compared with mirror-like polished substrate. The concentration of methane is critical factor that affected the nucleation density, grain size and developing facet. Furthermore, the transformation from nucleation to continuous film was revealed on side wall of the grooved substrate. And the nucleation growth mechanism of diamond on the 4H-SiC substrate was discussed, and a four-stage nucleation growth mechanism has been proposed with the formation of carbon clusters by converting from sp(1) to sp(2) and sp(3) carbon, shaping into preferred crystal planes and forming a well-defined cubo-octahedral diamond grains before producing a compact and coalesced diamond film.

Automated summary

In this study, diamond was deposited on mirror-like polished, grinded, and grooved 4H-SiC substrates using microwave plasma chemical vapor deposition. The effects of different growth time and concentrations of methane in hydrogen on the nucleation process and grain morphology were investigated. It was found that grinding the substrate significantly increased the nucleation density, and the concentration of methane played a crucial role in nucleation density, grain size, and facet development. The transformation from nucleation to continuous film was observed on the side wall of the grooved substrate.