3-D Numerical Characterization of a Microwave Argon PECVD Plasma Reactor at Low Pressure

A 3-D model of a microwave plasma (mwp)-enhanced chemical vapor deposition (PECVD) reactor at 2.45 GHz in argon at low pressure describing self-consistently, the coupling of the microwave energy into the plasma is presented. The characteristics of the discharge are simulated using a fluid plasma model which solves the electron and ion continuity equations, electron energy balance equation, and the Poisson's equation by finite element method, using COMSOL Multiphysics software. The physical behavior of the microwave PECVD discharge, such as plasma density, electron temperature, electric field and plasma potential, are simulated and analyzed. The chemical reactions considered in this paper are: elastic, superelastic, excitation, ionization, penning ionization and metastable quenching processes, involving electrons, ions (Ar
⁺
), neutral atoms (Ar), and excited metastable argon atoms (Ar*). The plasma characterization results are studied for a gas temperature of 300 K, a gas pressure of 100 mtorr and a microwave power of 600 W. The effect of varying gas pressure from 50 to 200 mTorr has been studied. The obtained results turn out to be in agreement with previous measurements and show that this kind of model can lead to a better understanding of the physical processes occurring in this kind of microwave reactor and thus allow optimization of this device.