Numerical model of rf glow discharges

Abstract

Theoretical predictions are given of the spatiotemporal distribution of charged-particle densities and electric field in a radio-frequency glow discharge. The model is based on a numerical solution of the continuity equations for electrons, positive ions, and negative ions coupled with Poisson’s equation. The influence of frequency and gas composition (electropositive versus electronegative gas) on the discharge properties is analyzed and compared (qualitatively) with experimental results. In the case of electronegative gas mixtures, and at low frequencies (of the order and less than the ion plasma frequency), the numerical model predicts the formation of double layers at the plasma-sheath boundaries, in agreement with recent experimental measurements based on spectroscopic plasma-diagnostic techniques.