Atomic-scale simulations of chemical vapor deposition on flat and vicinal diamond substrates

Abstract

The growth of diamond by chemical vapor deposition was simulated on nine substrates corresponding to flat and slightly miscut (1 0 0), (1 1 0), and (1 1 1) surfaces. The kinetics of the important surface reactions were input to a three-dimensional atomic-scale kinetic Monte Carlo model of film growth in various environments. The effects of the atmosphere near the growth surface and the atomic structure of the surface on growth behavior are ascertained. The differences in bonding configuration at the various atomic surface features have a strong effect on growth behavior, even when steric effects are not considered. Surface features that can grow by the addition of only one C atom from the gas grow faster than features that need more C atoms to propagate. This impacts not only the growth behavior of the flat (1 0 0), (1 1 0), and (1 1 1) faces which require one, two, and three C atoms to nucleate growth layers, respectively but also the growth of miscut substrates which contain steps that can grow much more quickly than the flat terraces. Acetylene is particularly important to growth on several of the surface orientations (e.g., (1 1 1)) because it aids in the formation of C clusters on the surface. The bonding geometries of the surface features on each of the nine substrate orientations are described, and their impact on growth behavior is demonstrated by altering the acetylene content of the gas near the growth surface.