BEN-HFCVD diamond nucleation on Si(111) investigated by HRTEM and nanodiffraction

The initial stages of diamond formation on firstly thinned Si(111) samples have been studied in a hot filament CVD (HFCVD) reactor by means of bright-field imaging and nanodiffraction experiments. Diamond crystals not resolved in high-resolution imaging are detectable using nanodiffraction. Nucleation mechanisms taking place during an HFCVD growth preceded or not by a bias treatment have been compared. The HRTEM observations strengthen previous reports concerning the smallest size of observable diamond islands. Finally, the bias effects on the surface morphology, on the nucleation density of diamond and on the orientation of diamond crystals versus the substrate are discussed. After bias, a matching between five {220} diamond and four {220} β-SiC planes in the [2-20] direction has been proposed. The former relationship is compared with previous studies of the diamond/β-SiC interface.