AVS 45th International Symposium
    Plasma Science and Technology Division Thursday Sessions
       Session PS-ThP

Paper PS-ThP4
Simulations of Electronegative Discharge Sheaths@footnote 1@

Thursday, November 5, 1998, 5:30 pm, Room Hall A

Session: Plasma Science and Technology Division Poster Session
Presenter: S.K. Kanakasabapathy, University of Texas, Dallas
Authors: S.K. Kanakasabapathy, University of Texas, Dallas
J.L. Kleber, University of Texas, Dallas
L.J. Overzet, University of Texas, Dallas
Correspondent: Click to Email
Measuring negative ion concentrations in discharges continues to be difficult. Negative ions do not easily escape the glow center and as a consequence are more difficult to probe than electrons or positive ions. When the negative ion concentration becomes a large enough fraction of the total negative charge, however, the plasma kinetics can become dominated by the ions, and the electrons can become relatively insignificant. This kind of plasma is sometimes referred to as an "ion-ion plasma." We have developed a one-dimensional, time dependent, fluid model (SHEATHSIM) to simulate the behavior of ions and electrons near RF biased electrodes, double probes and a novel four point probe in just such electronegative plasmas. In each sheath, the ion momentum conservation and continuity equations, closed by Poisson's equation are solved for a given set of bulk densities, temperatures and mean free path lengths. The set of equations for two such sheaths are closed by a common bulk potential and current continuity. Such modeling helps us to understand the measurements we are making of highly electronegative "ion-ion" discharges. In this poster, we will present the results from our simulation as compared to measurements made in SF@sub 6@ and Cl@sub 2@ discharges. @FootnoteText@ @footnote 1@ This material is based upon work supported by the National Science Foundation under Grant No. CTS-9713262 and by the State of Texas Advanced Research Program under Grant No. 009741-043.