Nucleation of boron nitride on cubic boron nitride microcrystallites using chemical vapor deposition

BN containing both cubic and turbostratic phases were synthesized using a chemical vapor deposition apparatus having a tungsten hot filament and a rf induction coil. The films deposited on the Si substrate demonstrated infrared absorption peaks at 800, 1080, and 1380 cm−1, suggesting that the deposited films contained both cubic and turbostratic BN. Transmission electron microscopy revealed that the BN films included clusters having 200–300 nm in size. In addition, it also appeared that these clusters were composed of crystalline cubic BN. To investigate the nucleation of BN on seed crystallites, cubic BN microcrystals were scattered on the Si single crystal wafer. On these crystallites, only submicron clusters were seen. These displayed broad Raman peaks at ∼1050 and ∼1300 cm−1, which are attributable to those from cubic BN. Thus, we suggest that the nano- crystalline cubic BN grew on cubic BN seeds possibly having preferential nucleation.