Deposition of diamond films on SiO2 surface using high power microwave enhanced chemical vapor deposition process

Diamonds were successfully nucleated on SiO₂-coated silicon substrates using high power microwave plasma enhanced chemical vapor deposition (CVD) process. Nucleation rate on SiO₂ surface (i.e., 0.5×10¹⁰ cm^-2) is, however, still smaller than that on Si surface (i.e., 1.0×10¹⁰ cm^-2). The growth of diamonds behaved similarly on the pre-nucleated surface, regardless of the nature of the substrates. Diamonds were of single grain columnar structure with random orientation when deposited without bias and were of multigrain columnar structure with [001] preferred orientation when deposited under -100 VDC bias. Multigrain columnar structure was ascribed to the induction of secondary nucleation at the presence of bias voltage