Irregularities in electronegative plasmas due to ion-ion coupling

Abstract

Summary form only given. In partially ionized electronegative plasmas at low neutral pressure and high plasma density, coupling between positive and negative ions through space charge effects and through Coulomb scattering can lead to turbulence and irregularities in the ion density and flux. In this regime, the force on ions due to ion-ion Coulomb scattering may dominate that from ion scattering with neutrals. This can lead to the formation of a, possibly turbulent, negative ion boundary layer containing the bulk of the negative ions. Commercial Inductively Coupled Plasma reactors used in the semiconductor industry typically operate at low pressure and high plasma density. Simulations are presented for a Chlorine discharge in the GEC reactor modified for Inductively Coupled operation. Results show that ion-ion coupling can induce large variations in the plasma density, and that accurate modeling of spatial plasma structure should include these effects.