Nucleation of diamond on Si cones by biased hot filament chemical vapor deposition

The nucleation and initial growth of diamond on Si cones were investigated by scanning election microscopy, micro-Raman spectroscopy and x-ray photoelectron spectra. The diamond films were deposited by biased hot filament chemical vapor deposition. Negative bias voltage relative to the filament of up to -300V was applied to the substrate through the Molybdenum holder, which resulted in measured current of up to 250mA. After the first 15 min to biased treatment, many cones with several micrometer high were appeared on the edges of Si substrate. More distinguishable diamond crystallites were grown on the tops of the cones during the next 20min. Experimental results showed that the cones were produced by plasma etching, and diamond nucleation was easily grown on the tops of Si cones due to that there are lots of micro-steps, defects and dangling bonds near the top of cones.