Modeling of hydrogen-based plasmas in microwave plasma-assisted chemical vapor deposition reactors at moderate pressures

Microwave Plasma-Assisted Chemical Vapor Deposition (MPACVD) systems are used in the deposition of high quality diamond films. These systems have traditionally been operated at less than 20% atmospheric pressure (atm), resulting in growth rates up to 5 μm/hr. Under such conditions, the system operation and plasma behavior are well-understood and have been successfully modeled. Recent experiments at pressures approaching 40% atm have demonstrated faster growth rates and better quality samples. At these increased pressures, the system operation and plasma behavior are not completely understood, with unusual plasma behavior sometimes observed. Experimental measurements within these systems can be difficult, making numerical models attractive for aiding in understanding this behavior. This thesis presents a self-consistent multiphysics numerical model of MPACVD systems, which is accurate under these operating conditions. Electromagnetic field propagation, chemical reactions, species diffusion, thermal processes, energy transfer, and convective flows are all included in the multiphysics model. The model is verified against canonical problems and validated against experimental data. Extensive numerical results are provided for different operating conditions and system configurations.