ON THE BEHAVIOR OF THE PENETRATION TWIN ABUNDANCE ON (100) DIAMOND FACETS

The morphology of isolated diamond crystals and diamond films can be s trongly influenced by twin nucleation. For a better understanding of t hese phenomena, a recently introduced new concept? the twin nucleation surface (a quantity proportional to the probability that a given poin t is overgrown by a twin) is defined and calculated for penetration tw ins on {100} facets. The results explain several experimental findings : the dependence of the twin abundance on the relative position on the {100} facet, on the growth parameter alpha = root 3 nu(100)/nu(111) a nd on the orientation of the twin with respect to the facet boundary. Also, the results offer an explanation for the existence of a narrow w indow of deposition conditions for which a growing film can rapidly ev olve to a high-quality film with a low twin concentration. (C) 1998 El sevier Science S.A.