Large area diamond nucleation on Si(001) using magnetoactive microwave plasma CVD

Uniform diamond nucleation was succeeded on Si(001) substrate over a large area (3 cm × 4 cm) by magnetoactive microwave plasma CVD. CH4He gas mixture was used as source gas in order to obtain high radical density in the nucleation step. The effect of substrate bias voltage on the nucleation was examined. The results show that a suitable positive bias voltage applied to the substrate can enhance diamond nucleation while negative bias voltages lead to the deposition of only non-diamond phase carbon. The CH3 radical density was measured using infrared laser absorption spectroscopy in order to investigate the effect of radical species on the nucleation. The results are discussed in relation to the important factors on the bias-enhanced diamond nucleation.