Diamond nucleation and growth from submicron amorphous carbon clusters containing randomly oriented diamond nanocrystallites

Diamond nucleation and growth from submicron clusters consisting of an amorphous carbon phase with predominantly sp3 atomic hybridization and randomly oriented diamond nanocrystallites was investigated by various microanalysis techniques. The carbon clusters were created by exposing a highly sp3 hybridized carbon thin film, deposited on a smooth silicon substrate by a vacuum arc method, to a low-temperature, methane-rich hydrogen plasma in a microwave plasma-enhanced chemical vapor deposition system. Diamond nanocrystallites inside the carbon clusters produced by the pretreatment acted as diamond nucleation sites. Microanalysis results provided insight into the structure and composition of the carbon clusters, the diamond nanocrystallites, and the amorphous ultrathin interlayers at the interfaces of the clusters and the grown diamond film with the silicon substrate. The physical phenomena responsible for the enhancement of diamond nucleation and growth on smooth substrates by the present method are interpreted in the context of the obtained results.