Nucleation and oriented textured growth of diamond films on Si(100) via electron emission in hot filament chemical vapor deposition

Oriented textured diamond films were obtained on Si(100) substrate via elec tron emission in hot filament chemical vapor deposition (HFCVD). A de bias voltage relative to the filament was applied to the tungsten electrode betw een the substrate and the filament. The nucleation and subsequent growth of diamond films were characterized by scanning electron microscopy and Raman spectroscopy. The experimental results showed that the electron emission f rom the diamond coating on the electrode played a critical role during the nucleation. The maximum value of nucleation density was up to 10(11) cm(-2) on pristine Si surface at emission current of 250 mA. The effect of the el ectron emission on the reactive gas composition was analyzed by in situ inf rared absorption, indicating that the concentration of CH3 and C2H2 near th e substrate surface was extremely increased. This may be responsible for th e enhanced nucleation by electron emission.