Modeling of substrate surface temperature distribution during hot-filament assisted diamond deposition

The importance of substrate temperature in determining the quality, uniformity and growth rate of diamond films is now well recognized. In the hot-filament assisted chemical vapor deposition of diamond, the mechanism of heat transfer is unique. In addition to conduction, convection and radiation, filament-to-substrate heat transfer takes place by dissociation of molecular hydrogen at or near the filament and recombination of atomic hydrogen at the substrate surface. In this paper, the role of atomic hydrogen recombination in heat transfer is examined. Furthermore, the effects of system geometry and process variables on the substrate temperature distribution are analyzed. The results indicate that atomic hydrogen recombination at the substrate plays a significant role in substrate heating. In hot-filament assisted diamond deposition, system geometry, filament temperature and pressure are the most important factors in determining the substrate temperature distribution.