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arXiv · 1909.10218

Electric field non-linearity in very high frequency capacitive discharges at constant electron plasma frequency

Sarveshwar Sharma·Nishant Sirse·Animesh Kuley·Miles M Turner
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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 non-linearity, 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. The driving frequency is varied from 27.12 MHz to 100 MHz for a discharge gap of 3.2 cm in argon at a gas pressure of 1 Pa. The simulation results provide insight of higher harmonic generations in a CCP system for a constant electron response time. The spatio-temporal evolution and spatial time averaged electron heating is presented for different driving frequencies. The simulation results predict that the electric field non-linearity 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 is observed in to the bulk plasma at higher driving frequencies. The EEDF illustrate 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.

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Sarveshwar Sharma, Nishant Sirse, Animesh Kuley, Miles M Turner. 2019-09-23. Electric field non-linearity in very high frequency capacitive discharges at constant electron plasma frequency. https://doi.org/10.1088/1361-6595/ab74b5

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