Design of a Microwave Plasma Enhanced Chemical Vapor Deposition System Using the Fluid Modeling based on the Finite Element Method

Microwave Plasma Enhanced Chemical Vapor Deposition (MPECVD) is one of the commonly used thinfilm manufacturing methods for diamond, graphene, etc. In an MPECVD system, the plasma consisting of ionized gas species and electrons is ignited and sustained by applying microwave, 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 fluid modeling based on finite element method (FEM) that incorporates many physical interfaces such as 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 conservation 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 TM011 mode. At an input power of 1 kW with the argon pressure varied from 600 to 1500 Torr, the plasma density increases from 2.35e17 to 4.34e17 1/m^3 reaching steady-state at around 0.1 seconds and a uniform argon plasmas are excited by the TM011 microwave resonance. Detailed analysis of the dependence of the MPECVD operation on different pressures and input powers will be presented.