We have combined radio frequency (RF) 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 W2C, W-δ-WB and W/Si2W. High-quality diamond film can only be prepared at Ts>700 °C by RF+HF-CVD and the contamination from tungsten filaments has been remarkably reduced by pre-heating the filament in CH4+H2 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.
Bibliographical noteFunding Information:
This work is supported by Foundation for University Key Teacher by the Ministry of Education and Natural Science Foundation of Gansu Province, China.
- Diamond film