DIAMOND NUCLEATION UNDER HIGH CH4 CONCENTRATION AND HIGH FILAMENT TEMPERATURE

Methane concentrations of 8-16% were applied to grow diamond by hot fi lament chemical vapour deposition. To study the nucleation behaviour w ith high methane concentrations, silicon substrates were polished with diamond and aluminum oxide. Atomic force microscopy (AFM) was used to examine the topography of the grown surface. Diamond nuclei were obse rved with density of 5 x 10(7) - 5 x 10(8) cm(-2), after 3-5 min depos ition, on diamond seeded substrate but not on Al2O3 polished surface. Instead of growing along the scratches induced by polishing, diamond n uclei developed directly on the matrix of an amorphous carbon layer co nfirmed by transmission electron microscopy. (C) 1998 Elsevier Science S.A.