Design and Simulation of a Microwave Plasma Enhanced Chemical Vapor Deposition System Operated at 2.45 GHz Using the Multiphysics Modeling based on a Finite Element Method

Microwave plasma enhanced chemical vapor deposition (MPECVD) is one of the most extensively used thin film manufacturing methods for growth of diamonds than any other plasma based systems. Microwave plasmas are different from other plasmas where the microwave frequency can oscillate electrons and the collision of electrons with gaseous atoms and molecules generates a high degree of ionization. Hence in an MPECVD system, by applying microwave the plasma can be ignited and sustained, where a thin film can be deposited at lower temperatures. This paper discusses the design of a 3-D MPECVD chamber operated at a 2.45 GHz of frequency using the Multiphysics modeling based on a finite element method (FEM) that incorporates many physical interfaces including laminar flow, heat transfer in fluids, plasma, and electromagnetic waves to give more self-consistent and accurate simulation results. The plasma discharge is modeled by coupling drift-diffusion, heavy species transport, and electric fields into a single multiphysics model. The conservations of mass and momentum are modeled in simulation by solving continuity and Navier-strokes equation, respectively. The geometrical design of MPECVD consists of a coaxial waveguide connected by slots to a cylindrical plasma chamber at the center to produce T'M
011
mode. With an input power of 1 kW at the input port of WR340 coaxial waveguide at 2.45 GHz with the argon pressure at the chamber varied from 600 to 1000 Torr, the plasma density increases from 5.51e16 to
$\mathbf{5}.\mathbf{81}\mathbf{e}\mathbf{161}/\mathbf{m}^{\mathbf{3}}$
reaching steady-state at around 5 msec and a uniform argon plasma is excited by the TM
011
cavity resonance. Detailed analysis of the dependence of the MPECVD operation on different pressures and input powers will be presented.