A study on nano-nucleation and interface of diamond film prepared by hot filament assisted with radio frequency plasma

We have combined radio frequency (R-F) plasma with hot filament (HF) chemical vapor deposition (CVD) together to investigate diamond growth. By modifying the conventional RF apparatus and tungsten arrangement in RF system, we systematically investigated the process of nucleation, interlayer formation and growth by atom force microscopy (AFM), X-ray diffraction (XRD) and Raman spectra. The experimental results showed that at low substrate temperature, nano-crystal diamond and other non-diamond carbons formed. The interface between the film and the substrate contained four components: SiC, tungsten (W), W/WC or W(2)C, W-delta-WB and W/Si(2)W. High-quality diamond film can only be prepared at T(s)>700 degreesC by RF+HF-CVD and the contamination from tungsten filaments has been remarkably reduced by pre-heating the filament in CH(4) + H(2) atmosphere and placing it as near the upper electrode as possible. Furthermore, large area diamond film can be easily synthesized by HF + RF-CVD method, which has more advantages than other methods. (C) 2002 Elsevier Science B.V All right reserved.