Research and Development of 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 thin film manufacturing methods for diamond, graphene, etc. In an MPECVD system, the plasma is confined to the center of the deposition chamber as a ball and uniformly distributed, preventing carbon deposition onto the walls of the chamber and microwave deposition is an electrode-less process hence contamination of the films due to electrode erosion is avoided, making it a best technique for diamond film growth. This paper discusses the design of a 3-D MPECVD chamber connected by slots to a coaxial waveguide and operated at a 2.45 GHz of frequency to produce TM011 mode 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 and the conservation of mass and momentum by solving continuity and Navier-strokes equation, respectively. At an input power of 1 kW with the argon pressure varied from 600 to 1400 Torr, the plasma density increases from 2.35e17 to 4.09e17 1/m^3, reaching steady-state at around 0.1 seconds and a uniform argon plasma is excited by the TM011 microwave resonance. The model is also tested at constant presure of 1,000 Torr and 760 Torr for different power levels, ranging from 800 W to 1 kW which produced a steady state plasma density in the range of 3.17e17 to 3.41e17 1/m^3 and 2.66e17 to 2.80e17 1/m^3, respectively.