Electric field nonlinearity in very high frequency capacitive discharges at constant electron plasma frequency

Sharma, S and Sirse, N and Kuley, A and Turner, MM (2020) Electric field nonlinearity in very high frequency capacitive discharges at constant electron plasma frequency. In: Plasma Sources Science and Technology, 29 (4).

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Abstract

A self-consistent particle-in-cell simulation study is performed to investigate the effect of driving frequency on the electric field nonlinearity, electron heating mechanism, and electron energy distribution function (EEDF) in a low pressure symmetric capacitively coupled plasma (CCP) discharge at a constant electron plasma frequency maintained by adjusting the discharge voltage. The driving frequency is varied from 27.12 MHz to 100 MHz for a fixed discharge gap of 3.2 cm and at a gas pressure of 1 Pa. The simulation results provide insight into higher harmonic generations in a CCP system for a constant electron response time. The spatiooral evolution and spatial time-averaged electron heating are presented for different driving frequencies. The simulation results predict that the electric field nonlinearity increases with a rise in driving frequency along with a concurrent increase in higher harmonic contents. In addition to the electron heating and cooling near to the sheath edge, a positive <J.E> is observed into the bulk plasma at higher driving frequencies. The EEDF illustrates enhancement in the population of mid-energy range electrons as driving frequency increases thereby changing the shape of EEDF from bi-Maxwellian to nearly Maxwellian. For the constant ion flux on the electrode surface, a decrease in the ion energy by more than half is observed with an increase in driving frequency.

Item Type:	Journal Article
Publication:	Plasma Sources Science and Technology
Publisher:	IOP PUBLISHING LTD
Additional Information:	The copyright of this article belongs to IOP PUBLISHING LTD
Keywords:	Distribution functions; Electron energy analyzers; Electron energy levels; Electrons; Ion beams; Plasma heating; Plasma simulation; Plasma waves, Capacitive discharges; Capacitively coupled plasmas; Driving frequencies; Electrode surfaces; Electron energy distribution functions; Electron plasma frequency; Particle-in-cell simulations; Very high frequency, Electric discharges
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	10 Aug 2020 10:10
Last Modified:	10 Aug 2020 10:10
URI:	http://eprints.iisc.ac.in/id/eprint/65243

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