MOLECULAR-DYNAMICS SIMULATIONS OF ATOMIC PROCESSES AT THE LOW-TEMPERATURE DIAMOND (111) SURFACE

The deposition of low-energy carbon atoms onto a low-temperature diamond (111) surface is studied by molecular-dynamics computer simulations. A Stillinger-Weber potential [F. H. Stillinger and T. A. Weber, Phys. Rev. B 31, 5262 (1985)], with a reparametrization derived from quantum-mechanical energy calculations for small tetrahedral carbon clusters, is used to model the interatomic interactions. The penetration of 1-100-eV neutral carbon atoms into the diamond (111) surface at 100 K and the resultant surface atom rearrangements and induced film stress are studied. For intermediate energies (20-60 eV) the incident atom penetrates beneath the exposed (111) surface and significantly increases the lateral compressive stress in the diamond film. The emerging picture is that diamond films grow from below the exposed surface in a region of locally high stress and tetrahedral coordination.