Kinetic Monte Carlo studies of early surface morphology in diamond film growth by chemical vapor deposition of methyl radical

We present results of off-lattice kinetic Monte Carlo simulations of early stages of low-pressure diamond film growth from a C[111] substrate via methyl radical and hydrogen vapor deposition. Interactions are governed by a semiempirical interatomic potential energy function. Rates for surface chemisorption and desorption of hydrogen and chemisorption of methyl radical that have been calculated by Raff and co-workers are used to assign real time to the Monte Carlo steps. The rate-determining step is the deposition or attempted deposition of methyl radical. Between CH3 surface events, the surface is relaxed by standard Monte Carlo methods. During the relaxation process C-C bonds may form and break, and surface diffusion occurs. We study the rate of formation of pair bonds and larger clusters of chemisorbed carbon over a 20-ms simulation, during which the initial surface becomes covered and small diamond ledges begin to form. This rate of growth is in accord with observed rates for diamond film growth from methyl radical.