Characterization of the transition from collisional to stochastic heating in a RF discharge

Abstract

In this work, we have studied the transition from collisional to stochastic heating regime in a RF inductively coupled plasma discharge, in which the exciting antenna is placed inside the vacuum chamber. The electron and ion energy distribution functions are obtained using an RF filtered electrostatic probe and a Faraday cup. The analysis of the energy distribution functions as a function of the working pressure reveals the existence of two distinct discharge regimes, which are governed by the heating processes. Our results show that while the electron distribution function is Druyvesteyn-like for high pressures, p ⩾ 4.0 × 10−2 mbar, it becomes bi-Druyvesteyn, and not bi-Maxwellian, as found in other works, for low pressures, p ⩽ 1.0 × 10−2 mbar.