Effect of discharge voltage on capacitively coupled, parallel plate rf hydrogen plasmas

Abstract

In this paper we present a parametric study of the effect of discharge voltage on capacitively coupled, parallel plate (CCPP) radio frequency discharges in pure hydrogen at low pressure, performed using a 1D(r)2D(v) particle in cell/Monte Carlo collision model with self-consistent neutral kinetics and also compare our results with experimental and theoretical ones reported in the literature. In the first part of the paper, we review the essential features of the numerical code, together with the database of plasma particles and neutral kinetics data. Results are discussed, in particular, for charged particle density and energy, the appearance of the double layer phenomenon, the plasma potential and the atom density. A possible role of photoelectric emission in the charged particle balance is also discussed.

From cold to fusion plasmas: spectroscopy, molecular dynamics and kinetic considerations

“…In [35] a connection was established between the profiles of the emission intensity and those of the electric field, providing a much convincing support to the sheath dynamic interpretation on an experimental basis. However, only in [36], for the first time, a theoretical calculation of the excitation rates of H(n=3) and ). Due to the low radiative lifetimes of the emitting states it was supposed that the population rate of these last is proportional to the emission intensity for both lines.…”

“…A qualitative agreement was found, with a reproduction of the double maxima of the space emission profile of both lines and a semi-quantitative agreement concerning the location of these features, which was found to depend weakly on the discharge voltage when this last was high enough to allow the feature to appear. We show for the first time results based on an updated version of the model in [36]. The improvements concern the possibility to deliver space-time plots of the population rates and the inclusion of a more consistent set of cross sections for the Balmer-α emission via H 2 (X 1 Σ + g ,ν) dissociation to H(n=3), based on the latest results in [37,38].…”

“…The vibrational excitation of the molecular target acts enhancing the process probability, showing the dependence on ν a strongly irregular behavior that follows closely the behavior of corresponding Franck-Condon density. In figures 9 a and b we report results for the excitation rate of H 2 (d 3 Π u ) as a function of space and RF phase in the same conditions in [36] at two different voltages. In these figures the time is measured in terms of phase with respect to the RF oscillation at 13.56 MHz: the population rate increases when the sheath dynamics heats up the free electron cloud and increases the value of the eedf beyond the process threshold.…”

Multispecies Particle Simulation of the Hydrogen Plasma Sheath Region

“…[1][2][3]. The 1D(r)2D(v) fully self-consistent particle/continuum model, includes a state-to-state reactiondiffusion part for the vibrational distribution and atomic fraction implemented through a grid-discretized relaxation technique.…”

“…The Bari group has developed in the last 10 years a PIC/MCC model for H 2 plasmas including chemical issues and wall interaction [1][2][3] which can be of interest in this case in view of its characteristics:…”