Modeling of convective plasma flow in high pressure microwave PACVD diamond reactors

Summary form only given. Microwave plasma-assisted chemical vapor deposition (PACVD) reactors have been used extensively for the growth of synthetic diamond. Simulations of such reactors have been developed in order to aid in the testing of new designs and parameters. Since this type of diamond growth has historically been carried out at relatively low pressures (less than 100 Torr), the plasma transport properties have been approximated as purely diffusive. However, recent experiments citing numerous advantages of growing at higher pressures (100-300 Torr) have suggested this approximation to be insufficient. Thus, a more advanced transport model accurately predicting complex convective plasma flows is required. This paper details a self-consistent multi-physics model that simulates microwave PCAVD diamond reactors at higher pressures of 100-300 Torr. As with previous simulations, a finite-difference electromagnetic simulation is coupled to a plasma fluid model, converging on a self-consistent solution. However, this new simulation includes a time-dependent fluid flow plasma model which includes diffusion, conduction, and convection processes. Moreover, a reactor geometry temperature profile model is also inserted into the solution scheme. The absorbed power within the plasma is passed to the plasma model, while the neutral species temperature, and electron temperature and density are converted to conductivity and passed to the electromagnetic simulation. This process is iterated until a stable solution is achieved. Numerical results of electromagnetic power distribution, species concentration, temperature profiles, and temporal solution convergence will be presented. These results will also be compared to selected experimental data.