BEN-HFCVD effects on diamond nucleation on iridium: a Raman imaging study

Diamond crystallites grown on Ir/SrTiO, substrates after a bias-enhanced nucleation procedure in a hot filament reactor have been studied using Raman spectroscopy. In particular, two techniques, Raman imaging and Raman mapping have been employed, and some of their relative merits for the detection of small diamond particles are presented. Part of the present results tend to indicate that the bias-enhanced nucleation process in hot filament reactors differs significantly from the corresponding one in microwave plasma reactors. In particular, a thin layer of graphitic carbon is systematically detected at the iridium surface. It is speculated that the presence of this layer prevents the oriented nucleation and growth of the diamond crystallites.