Kinetic Simulation of He radio frequency capacitive coupled plasma

TL;DR

This paper uses Particle-in-Cell simulations to analyze how varying radiofrequency parameters affect the sheath, plasma density, and ion distributions in helium capacitive plasma, revealing control mechanisms for plasma processing.

Contribution

It provides a detailed kinetic simulation study of RF capacitive helium plasma, highlighting how different frequency amplitudes and phase shifts influence plasma characteristics and dynamics.

Findings

Increasing RF amplitude raises plasma density and sheath potential.

Adjusting phase shifts alters ion energy and angular distributions.

Harmonics can be excited in the discharge current due to sheath-bulk interplay.

Abstract

Radiofrequency capacitively coupled plasma is studied theoretically using a Particle-in-Cell code. For He discharge, the time-averaged sheaths are in the range of few centimeters. The sheath potential, ion, and electron energy and angular distributions, discharge current, and dissipated power depend on the driven potentials and frequencies. Increasing the amplitude of the high radio frequencies increases the bulk density and the sheath potential and, consequently, increases the plasma processing rate. Increasing the intermediate radio frequency amplitude allows a wider sheath with a broad ion energy distribution and a narrower ion angular distribution. Changing the amplitude and the phase shift between driven frequencies provide different energies and angular distribution allowing performing various processes. The interplay between the sheath and bulk dynamics in the intermediate radiofrequency regime and the high-frequency regime may excite harmonics in the discharge current.