Electron energy distribution function and plasma potential in a planar inductive argon discharge without electrostatic screen

Abstract

Studies on electron heating are done during the power coupling change in the discharge mode transition (E–H mode transition) in a planar inductive argon discharge without electrostatic screen (Faraday shield). The electron energy distribution function (EEDF) evolution is measured by the alternating current superposition method with a radio frequency (rf) compensated Langmuir probe. The trend of its integrals, electron density and effective electron temperature, and especially the plasma potential against rf power are presented. It is demonstrated that the plasma potential is governed primarily by the high-energy electron tail in a plasma with bi-Maxwellian EEDF. The interdependence of the EEDF and the plasma potential is discussed. The experimental results show that the plasma potential against rf power reflects a change in the relative contribution of capacitive power coupling to electron heating.