THE FORMATION OF ATOMIC STEPS IN CHEMICAL-VAPOR-DEPOSITION DIAMOND GROWTH

A mechanism for the formation of atomic steps in chemical vapour depos ition diamond growth is proposed. First, a number of groups is adsorbe d on the diamond (111) surface, each of which consists of three neighb ouring methyl radicals, and there are small steric repulsions among th ese groups because of the large distances between them; second, the th ree CH3 radicals in each of the groups are bound to form the step diam ond structure via H abstraction of hydrogen atoms and CH3 radical inte rmediates. The epitaxial growth possibly proceeds on addition of a cer tain species, such as C2H2 or CH3 addition, until it encounters anothe r step structure from epitaxial growth of another group of CH3 radical s. Once the atomic steps are flattened, the process will be repeated a gain. This mechanism is supported by the results of first-principles d iscrete variational method calculations and is consistent with the con clusions reported in the literature.