Electron dynamics in planar radio frequency magnetron plasmas: III. Comparison of experimental investigations of power absorption dynamics to simulation results

TL;DR

This paper investigates electron power absorption in magnetron RF plasmas through experimental phase-resolved optical emission spectroscopy and 2D particle-in-cell simulations, revealing magnetic field effects on electron trapping and acceleration.

Contribution

It provides a combined experimental and simulation analysis of electron dynamics in magnetized RF discharges, highlighting magnetic field influences on electron trapping and acceleration mechanisms.

Findings

Magnetic flux density significantly alters electron dynamics.

Electric field reversal enhances electron acceleration during sheath collapse.

Experimental results are supported by detailed 2D PIC simulations.

Abstract

In magnetized capacitively coupled radio-frequency discharges operated at low pressure the influence of the magnetic flux density on discharge properties has been studied recently both by experimental investigations and in simulations. It was found that the Magnetic Asymmetry Effect allows for a control of the DC self-bias and the ion energy distribution by tuning the magnetic field strength. In this study, we focus on experimental investigations of the electron power absorption dynamics in the presence of a magnetron-like magnetic field configuration in a low pressure capacitive RF discharge operated in argon. Phase Resolved Optical Emission Spectroscopy measurements provide insights into the electron dynamics on a nanosecond-timescale. The magnetic flux density and the neutral gas pressure are found to strongly alter these dynamics. For specific conditions energetic electrons are efficiently trapped by the magnetic field in a region close to the powered electrode, serving as the target surface. Depending on the magnetic field strength an electric field reversal is observed that leads to a further acceleration of electrons during the sheath collapse. These findings are supported by 2-dimensional Particle in Cell simulations that yield deeper insights into the discharge dynamics.