Nucleation enhancement of diamond by electric arcing

Enhancement of diamond nucleation by arcing on pre-existing diamond particl es has been studied in the hot-filament CVD process. A positive bias of 400 volt was applied on a wire hanging over a grounded substrate. Electric arc ing between the wire and the substrate occurred during heating the filament in the temperature range 900-2000 degrees C, and resulted in an enhancemen t of nucleation around the pre-existing diamonds. The nucleation behavior w as different from that of the conventional bias-enhanced nucleation, but th e maximum nucleation density was almost the same. Based on the observed mic rostructural features, the enhanced nucleation mechanism was proposed to be the fragmentation of diamond particles during arcing. (C) 1998 Published b y Elsevier Science S.A. All rights reserved.