Characterization of time-modulated inductively coupled and capacitively coupled plasmas

Abstract

Summary form only given. Time-resolved probe measurements are carried out using the boxcar measurement method in pulsed and low- pressure inductively coupled plasma. The characteristics of the transient behavior of electron energy distribution function (EEDF) and plasma parameters such as electron density, electron temperature, and plasma and floating potentials are presented and analyzed with global model of pulsed discharge. It is found from the relaxation behavior of the EEDF and the analysis of the characteristic relaxation times of the electron density and temperature that the initial fast relaxation of high-energy electrons just after the power is turned off is dominated by electron-atom inelastic collisions rather than the diffusive cooling effect at low pressure. A revised global model in which the effect of electron-atom inelastic collisions is included is presented. After the power is turned on, an initial very sharp rise in electron temperature followed by a decay of electron temperature is observed and the peak electron temperature is found to increase with reducing the duty cycle of the power pulse. The comparison of the measured EEDFs shows that the increase of the peak electron temperature under shorter duty cycle pulse is caused by the depopulation of low-energy electrons, not by the overpopulation of high-energy electrons