Plasma series resonance in the E mode of low-pressure inductively coupled noble gas discharges

Abstract

When operated at low pressure, plasma discharges bounded by radiofrequency (rf)-driven sheaths exhibit high harmonics in the discharge current, which occur due to the nonlinear charge–voltage relation of the sheath. This phenomenon is well known from capacitive rf discharges and commonly called the plasma series resonance (PSR) effect. Rf inductively coupled plasmas (ICPs) operated at low power are usually mainly driven capacitively (E mode) and act similar to capacitive discharges (CCPs), which includes the occurrence of the series resonance effect. In this communication the effect is investigated experimentally and compared with a simple global model which is an extension of existing CCP models to the ICP. Additionally, the influence of the series resonance on the electron energy distribution is investigated.