2016/02/04 by Julian Schulze, Schulze, J., Zoltán Donkó +7
Engineering · Medicine · #Electrostatic Discharge in Electronics #FOS: Physical sciences #Plasma Applications and Diagnostics #Plasma Diagnostics and Applications #Plasma Physics (physics.plasm-ph)
paper · pdf · doi:10.48550/arxiv.1602.01719
openalex publication_date 2016/02/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We investigate the electron heating dynamics in electropositive argon and\nhelium capacitively coupled RF discharges driven at 13.56 MHz by Particle in\nCell simulations and by an analytical model. The model allows to calculate the\nelectric field outside the electrode sheaths, space and time resolved within\nthe RF period. Electrons are found to be heated by strong ambipolar electric\nfields outside the sheath during the phase of sheath expansion in addition to\nclassical sheath expansion heating. By tracing individual electrons we also\nshow that ionization is primarily caused by electrons that collide with the\nexpanding sheath edge multiple times during one phase of sheath expansion due\nto backscattering towards the sheath by collisions. A synergistic combination\nof these different heating events during one phase of sheath expansion is\nrequired to accelerate an electron to energies above the threshold for\nionization. The ambipolar electric field outside the sheath is found to be time\nmodulated due to a time modulation of the electron mean energy caused by the\npresence of sheath expansion heating only during one half of the RF period at a\ngiven electrode. This time modulation results in more electron heating than\ncooling inside the region of high electric field outside the sheath on time\naverage. If an electric field reversal is present during sheath collapse, this\ntime modulation and, thus, the asymmetry between the phases of sheath expansion\nand collapse will be enhanced. We propose that the ambipolar electron heating\nshould be included in models describing electron heating in capacitive RF\nplasmas.\n