Results of a thermodynamic analysis of the processes proceeding on diamond (111) faces in hydrogen-rich environments were presented. It was shown that the key role of atomic hydrogen was to inhibit hydrogen desorption and subsequent surface reconstruction which was accompanied by the formation of sp2 hybridized structures on the surfaces of growing crystals. Such structures provided a template for graphite, rather than diamond formation. Furthermore, a high concentration of atomic hydrogen promoted the formation of saturated carbon-hydrogen clusters on the diamond crystal surfaces which led to extension (growth) of the pre-existing diamond lattice. The model correctly predicted the experimentally determined proportionality between the growth rate and the concentration of atomic hydrogen as well as trends in growth rate and diamond film quality as a function of methane concentration.

Role of Atomic Hydrogen in Preventing Surface Reconstruction and sp2 Bond Formation during Chemical Vapour Deposition of Diamond. W.Piekarczyk, S.Prawer: Diamond and Related Materials, 1993, 2[1], 41-7