Theoretical study of chemical reactions on CVD diamond surfaces

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