Influence Of Duty Cycle On Pulse Modulated Rf Capacitively-Coupled Argon Discharge

Abstract

Pulsed rf capactively-coupled discharge has attracted a lot of attention recently due to its widely applications in industrial film processes. In order to further optimize the plasma properties, a Particle-in-Cell simulation with Monte Carlo collisions was developed to explore the influence of pulsemodulated duty cycle on the sustaining of discharge and the fundamental plasma characteristics in the afterglow of pulse modulated RF capactively-coupled argon discharge at high pressure (0.3–1 Torr). It is found that, compared with the continuous wave rf plasma, the pulsed-modulated rf discharge can be sustained at a more broad driving frequency range, moreover, it can achieve higher electron density with lower electron energy for low driving frequency. At the pressure of 0.3 Torr, the electron density first decreases and then increases with the increasing duty ratio, with critical point around 2.5 MHz, while the electron temperature is inverse to that behavior. At the pressure of 1 Torr, the electron density shows the same pattern, with critical point around 6 MHz, while the electron temperature is always lower for the lower duty cycle.