DIRECT SIMULATION MONTE-CARLO STUDY OF H H-2 AND H/H-2/CO MIXTURES FOR DIAMOND CHEMICAL-VAPOR-DEPOSITION/

One-dimensional direct simulation Monte Carlo calculations have been c arried out on H/H-2 and H/H-2/CO mixtures under operating conditions t ypical of diffusion-dominated diamond chemical vapor deposition proces ses. Mechanisms have been included in the model for the adsorption and recombination of hydrogen atoms on the diamond surface and the dissoc iation of molecular hydrogen at the interior of the reactor. Hydrogen atom fluxes and recombinative and conductive heat fluxes to the diamon d surface are calculated as a function of pressure, gas composition, h ydrogen dissociation and surface reaction probabilities, reactor tempe rature, and distance between the activating source and substrate. The numerical calculations are shown to be in excellent agreement with ana lytical results in the limiting regimes of free-streaming particles at low pressures and continuum hydrodynamics at high pressures. (C) 1996 American Institute of Physics.