SURFACE ENERGIES AND MORPHOLOGIES OF CHEMICAL-VAPOR-DEPOSITED DIAMOND FILMS

Using a model where a fraction of carbon dangling bonds on the growth surface are saturated by hydrogen, the surface energies of chemical-vapor- deposited diamond crystals during the preparation process have been calculated. The results show that the surface energies increase with the increasing substrate temperature, and the surface energy-temperature curves of the three most energetically favored crystal planes, (100), (110), and (111), intersect at a critical substrate temperature. Then, the changes of predominant facets in the surface morphology from {100} to {111} with the increasing substrate temperature can be interpreted. Furthermore, it is found that the surface energies of diamond are lower than that of graphite in the chemical-vapor- deposition process of diamond. © 1994 American Institute of Physics.