Chemical Kinetic Calculations Of The Gas Phase In Atmospheric Pressure Microwave Plasma-Assisted Chemical Vapour Deposition Of Diamond

Abstract

The authors develop a numerical model for the atmospheric pressure microwave plasma chemical vapour deposition (CVD) of diamond in a two-dimensional field. The continuity, momentum, energy, and chemical kinetic calculations are carried out using a finite-difference control volume method. The microwave dissipated power was calculated using Maxwell’s equations. The temperature field, stream lines, and species concentration profiles were obtained for two different MW powers. We found that the species concentrations inside the MW reactor are not in chemical equilibrium, and the viscosity and thermal conductivity of pure hydrogen may be used as the mixture properties without any major loss of accuracy. However, these properties must be calculated based on the local concentrations of atomic and molecular hydrogen. By increasing the power, we increase the molar ratio of [H]/[CH3], which is advantageous in the CVD of diamond, and the product of [H]Ð[CH3] does not change. The latter parameter affects the rate of diamond growth. We also found that at low microwave power the effect of the thermal diffusion can be negligible.