Two-dimensional simulation of a pulsed-power electronegative discharge

Abstract

A two-dimensional self-consistent fluid model was developed to study the spatio-temporal dynamics of a pulsed power (square-wave modulated) inductively coupled electronegative (chlorine) discharge. The coupled equations for plasma power deposition, electron temperature, and charged and neutral species densities were solved simultaneously to capture the spatio-temporal evolution of the discharge. Simulation results showed separation of the plasma into an electronegative core and an electropositive edge during the active glow (power on) fraction of the cycle, and the formation of a positive ion/negative ion (ion-ion) plasma in the afterglow (power off) fraction of the cycle. During the early active glow, the negative ion flux is convection dominated near the quartz window under the planar coil of the ICP reactor. This is due to the emergence of relatively large electrostatic fields, leading to a self-sharpening negative ion front propagating into the plasma.