Theoretical study of chemical reactions on CVD diamond surfaces

The beta-scission growth mechanism at the diamond (100)(2x1) surface is studied by a combination of nanoscale ab-initio LDA/GGA and semiempirical tight-binding techniques to provide the necessary input into the mesoscale variable rime step Kinetic Monte Carlo (KMC) simulations of CVD diamond growth. The reaction path of the beta-scission reaction is critically examined, and the activation barrier of the reverse etching of the methylene adsorbate is deduced. We also considered the energetics of possible adsorbate configurations and showed that the removal of methylene (CH2) moieties from terrace and step edge sites is not appreciable. This 'preferential etching' of isolated CH2 from the (100) surface by atomic hydrogen effectively creates a barrier to (100) Layer nucleation. (C) 2000 Elsevier Science S.A. All rights reserved.