Investigating the effects of electron bounce-cyclotron resonance on plasma dynamics in capacitive discharges operated in the presence of a weak transverse magnetic field

TL;DR

This study explores how electron bounce-cyclotron resonance enhances plasma density and ion flux in capacitive discharges under weak magnetic fields, revealing optimal conditions and effects on electron and ion dynamics at low pressures.

Contribution

It provides a detailed analysis of electron bounce-cyclotron resonance effects on plasma behavior, expanding understanding of resonance conditions and their impact on discharge performance.

Findings

Maximum ionization and stochastic heating occur at resonance.

Electron tail population peaks at resonance conditions.

EBCR effects diminish with increasing neutral gas pressure.

Abstract

Recently, S Patil et al. have reported the existence of an enhanced operating regime when a low-pressure (5 mTorr) capacitively coupled discharge (CCP) is driven by a very high radio-frequency (60 MHz) source in the presence of a weak external magnetic field applied parallel to its electrodes. Their Particle-in-Cell (PIC) simulations show, that a significantly higher bulk plasma density and ion flux can be achieved at the electrode when the electron cyclotron frequency equals half of the applied RF frequency for a given fixed voltage. In the present work we take a detailed look at this phenomenon and further delineate the effect of this "electron bounce cyclotron resonance (EBCR)" on the electron and ion dynamics of the system. We find that the ionization collision rate and stochastic heating is maximum under resonance condition. The electron energy distribution function also indicates that the population of tail end electrons is highest for the case where EBCR is maximum. Formation of electric field transients in the bulk plasma region are also seen at lower values of applied magnetic field. Finally, we demonstrate that the EBCR induced effect is a low pressure phenomenon and weakens as the neutral gas pressure increases. The potential utility of this effect to advance the operational performance of CCP devices for industrial purposes is discussed.