Plasma asymmetry and electron and ion energy distribution function in capacitive discharges excited by tailored waveforms

Sharma, Sarveshwar and Sirse, Nishant and Kuley, Animesh and Turner, Miles M (2022) Plasma asymmetry and electron and ion energy distribution function in capacitive discharges excited by tailored waveforms. In: Journal of Physics D: Applied Physics, 55 (27). ISSN 0022-3727

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Abstract

Using a particle-in-cell simulation technique, we investigate the plasma and ionization asymmetry, higher harmonics generation, and electron and ion energy distribution function (IEDF) in capacitive discharges excited by tailored waveforms. At a base frequency of 13.56 MHz, three different waveforms, namely sinusoidal, sawtooth, and square, are applied for a constant current density amplitude of 50 A m−2 and gas pressure of 5 mTorr. The simulation results show that the square waveform produces the highest plasma density in the discharge, whereas maximum asymmetry is observed for plasma excited by the sawtooth-like waveform. Both square and sawtooth waveforms generate multiple beams of high-energy electrons from near to the expanding phase of the sheath edge and high-frequency modulations up to 100 MHz on the instantaneous sheath position. The electron energy distribution function depicts three electron temperature and highly elevated tail-end electrons for the square waveform in comparison to the sinusoidal and sawtooth waveform. The IEDF is bimodal at both the powered and grounded electrodes with a large asymmetry and narrow-type distribution in the case of the sawtooth-like waveform. These results suggest that the choice of waveform is highly critical for achieving maximum asymmetry and plasma density simultaneously in capacitive discharges.

Item Type:	Journal Article
Publication:	Journal of Physics D: Applied Physics
Publisher:	IOP Publishing Ltd
Additional Information:	The copyright of this article belongs to the Authors.
Keywords:	capacitive discharges; electron and ion energy distribution function; higher harmonics; PIC simulation; plasma asymmetry; tailored waveform
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	24 May 2022 08:54
Last Modified:	24 May 2022 08:54
URI:	https://eprints.iisc.ac.in/id/eprint/72325

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