Modelling of a Toroidal Wave Heated Plasma Source for the Remote Generation of Neutral Radicals

Remote plasma sources facilitate the production of neutral radical species for use in processing reactors which themselves cannot withstand exposure to charged species and radiative fluxes. Development of numerical models of power deposition in intermediate-to-high density plasmas, such as those used in remote plasma sources, is of importance to plasma-assisted material manufacturing and aerospace applications. In this work, results will be discussed from 2D fluid/Monte-Carlo simulations of a transformer-coupled radio-frequency (RF) toroidal remote plasma source sustained in argon and NF₃. A self-consistent treatment of the neutral gas temperature and associated inhomogeneous neutral depletion, is included in the model. Paschen breakdown and ignition criteria will be discussed through an analysis of the loop electric field topology for varying pre-ignition chamber pressures and gas admixtures. The inductive power deposition was investigated varying operating frequency, gas mixture, and chamber pressure. The degree to which these operating parameters affect ionization, and neutral species transport will also be discussed.