DEPOSITION OF DIAMOND FILMS ON SIO2 SURFACES USING A HIGH-POWER MICROWAVE ENHANCED CHEMICAL-VAPOR-DEPOSITION PROCESS

Diamonds were successfully nucleated on SiO2-coated silicon substrates using a high power microwave plasma enhanced chemical vapor depositio n process. Nucleation rates on SiO2 surfaces (i.e., 0,5 X 10(10) cm(-2 )) were, however, still smaller than those on Si surfaces (i.e., 1.0 X 10(10) cm(-2)). The major advantage in using high power microwaves wa s revealed by optical emission spectroscopy to be that the atomic C an d H species produced are more abundant and energetic. Therefore, the n egative bias effect is enabled and the formation of sp(3) bonds is enh anced. The nucleation of diamonds on SiO2 surface is thus made possibl e. The growth of diamonds behaved similarly on the prenucleated surfac e, regardless of the nature of the substrates, Diamonds were of single grain columnar structure with random orientation when deposited witho ut bias and were of multi-grain columnar structure with [111] or [001] preferred orientation when deposited under -100 V de bias. Multi-grai n columnar structure was ascribed to the induction of secondary nuclea tion at the presence of bias voltage. (C) 1997 American Institute of P hysics.