THE EFFECTS OF THE SIMULTANEOUS ADDITION OF DIBORANE AND AMMONIA ON THE HOT-FILAMENT ASSISTED CHEMICAL-VAPOR-DEPOSITION OF DIAMOND

The effects of the simultaneous addition of diborane and ammonia on th e nucleation density and growth rate of diamond prepared by hot-filame nt assisted chemical vapor depositions were examined. The diamond nucl eation density and growth rate decreased as the B/C and N/B input rati os were increased owing to poisoning of the diamond surface and deplet ion of methyl radicals. This reduction in the amount of diamond could be compensated for by increasing the substrate and filament temperatur es, and increasing the concentration of diamond growth species. Up to a B/C input reactant gas ratio of approximately 0.1, faceted diamond p articles and an amorphous B-C-N continuous film were codeposited. For B/C>0.1, only the B-C-N film was formed.. (C) 1998 Elsevier Science S. A.