Interaction of hydrogen and CFy radicals on the diamond (100)2 × 1 surface: an ab initio study

In this work mechanistic aspects of the ALE and CVD growth of diamond from CFy radicals are examined by means of ab initio calculations on the dimer-reconstructed C(100)2 × 1 surface. As models for the 2 × 1 reconstructed and unreconstructed (100)1 × 1 surfaces we have used C9 and C10 clusters comprising the basic structural unit of the diamond lattice with one surface dimer. The surface dimer and RCFy bond lengths, RCFy and RCF2F bond energies, activation energies for abstraction of fluorine from the chemisorbed CF3 group, and heats of reaction for addition of a carbon adspecies into a new diamond layer have been determined along with the effects of the lattice constraints on surface structures. Heats of a 1,2 fluorine transfer reaction on the surface has also been determined. The implications of the present results for halogen-assisted diamond growth by ALE and CVD are discussed.