Electron power absorption mode transition in capacitively coupled Ar/CF₄ discharges: hybrid modeling investigation

Abstract

In this work, the electron power absorption mode transition in capacitively coupled Ar/CF4discharges is investigated by using a one-dimensional fluid/electron Monte Carlo hybrid model. Different electron power absorption modes are observed under various external discharge conditions, which could be explained by examining the contribution of bulk electrons and secondary electrons respectively. The results indicate that as the gap increases, the electron power absorption mode changes from the drift-ambipolar (DA) mode to a α-γ-DA hybrid mode. This is ascribed to the enhanced ionization process of secondary electrons due to their sufficient collisions when the discharge region expands, as well as the weakened drift and ambipolar electric fields. By increasing the secondary electron emission (SEE) coefficient, the number density of secondary electrons grows, and thus the discharge experiences a transition from a α-DA hybrid mode over a α γ- -DA hybrid mode and finally into the γmode. Moreover, when the proportion of CF4 increases, the discharge tends to be more electronegative. As a consequence, the discharge gradually transits from a α-γ hybrid mode over a α- -DA hybrid mode, and finally to the DA mode.γ

Effect of gas flow on the nanoparticles transport in dusty acetylene plasmas

“…In the capacitively-coupled RF atmospheric-pressure electronegative gas (C 2 H 2 ) discharges, the drift and ambipolar fields play a dominant role in sustaining the discharges, and the electronegativity increases with pressure. Thus, the results are restricted to the drift-ambipolar regime [30][31][32]. The gas flow effect on the plasma properties and nanoparticle behavior is a critical problem, thus the neutral gas inlet velocity varies from 0 to 4.0 m s −1 .…”