Deposition of diamond films on SiO/sub 2/ surface using high power microwave enhanced chemical vapor deposition process

Diamonds were successfully nucleated on SiO/sub 2/-coated silicon substrates using high power microwave plasma enhanced chemical vapor deposition (CVD) process. Nucleation rate on SiO/sub 2/ surface (i.e., 0.5/spl times/10/sup 10/ cm/sup -2/) is, however, still smaller than that on Si surface (i.e., 1.0/spl times/10/sup 10/ cm/sup -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.