EFFECTS OF TEMPERATURE AND FILAMENT POISONING ON DIAMOND GROWTH IN HOT-FILAMENT REACTORS

The growth of diamond in a hot-filament reactor has been modeled, and compared with existing experimental data. Studies have been carried ou t on non-growth systems containing only hydrogen, as well as on system s where the methane concentration at the inlet was varied between 0.4% and 7.2%. The one-dimensional stagnation flow model used here include s detailed gas-phase and surface kinetics. A simple model of filament poisoning has been implemented. The effect of the gas/filament tempera ture discontinuity on species distributions has also been examined. Gr oss errors between theory and experiment are obtained when filament po isoning is neglected, but good agreement is found using a simple linea r poisoning model. A nonzero temperature discontinuity at the filament produces good overall agreement with experiment.