Kinetic simulations of capacitively coupled plasmas

Abstract

Summary form only given, as follows. Low-pressure capacitively coupled plasmas (CCPs) are widely used for various, applications. The simulation models, of CCP are mainly based on either fluid description of electrons or Particle-in-Cell with Monte Carlo (PIC-MC) models The fluid models are-not adequate for low-pressure CCPs since the electron distribution function (EDF) is strongly non-Maxwelian. The PIC-MC models are numerically expensive arid suffer from various drawbacks such as numerical heating. To model CCPs kinetically we use the recently developed multi-dimensional Boltzmann solver which is self-consistently coupled with the Poisson solver and other modules such as Chemistry Module. The Boltzmann solver incorporates various advanced techniques such as the use of total energy /spl epsiv/ with instantaneous potential /spl phi/(t, r~). The electron kinetic equation for the EDF f/sub 0/(t, r~, /spl epsiv/)is written as /spl part/f/sub 0///spl part/t+/spl part/e/spl phi///spl part/t /spl part/f/sub 0///spl part//spl epsiv/ = /spl nabla/D/sub r//spl nabla/f/sub 0/+1/N(u) /spl part///spl part//spl epsiv/ (N(u)[D/sub /spl epsiv// /spl part///spl part//spl epsiv/ f/sub 0/+V/sub /spl epsiv//f/sub 0/]), where D/sub /spl epsiv// and V/sub /spl epsiv// are diffusion and drift in energy space, and S describes inelastic collision processes, as well as Coulomb collisions. The term with /spl part//spl phi///spl part/t describes drift along the total-energy axis by virtue of time varying /spl phi/ and it turned out to important in this formulation. The developed model is fully 3D and can be applied to low-pressure, as well as high-pressure, CCPs. We apply the model for simulations of low-pressure CCPs in Argon and Helium in 1D and 2D. We obtain various scaling laws such as voltage-current characteristics and compare results with available experimental data.