Low-current medium-pressure RF discharge with electron photoemission in the electrode sheath and penetration of the sheath electrons into the discharge column

Journal Article · Sat Dec 15 04:00:00 EST 2007 · Plasma Physics Reports

DOI:https://doi.org/10.1134/S1063780X07120094· OSTI ID:21100111

Baranov, I Ya; Koptev, A V ^[1]

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1. Ustinov Baltic State Technical University (Russian Federation)

A model is developed for simulating a low-current moderate-pressure RF discharge with allowance for such characteristic discharge properties as the existence of two sheaths near both electrodes throughout the RF field period; the formation of an electron cloud at the sheath boundary that periodically fills the sheath and leaves it, depending on the phase of the applied RF voltage; the production by the sheath electrons of metastable gas particles that interact with the cloud electrons during subsequent field periods, followed by the excitation of metastable states to the emitting levels; the formation of a sheath in a low-current RF discharge due to the overlap of the secondary electron avalanches triggered by electron photoemission from the electrode surface; and the conditions under which the sheath electrons penetrate into the positive column and accumulate there, which makes, thereby making a low-current RF discharge similar to a non-self-sustained discharge. The parameters of the sheath in a low-current RF discharge are determined by the conditions under which the electron photoemission current from the electrode surface in the sheath is self-sustaining and, like the parameters of the positive discharge column, depend on the sort of gas, the gas pressure, the frequency of the applied RF field, and the interelectrode distance. The results of calculating the parameters of the sheath and column of a low-current RF discharge for nitrogen and helium at different pressures, as well as for different field frequencies and interelectrode distances, are presented and are compared with the experimental data.

• OSTI ID: 21100111
• Journal Information: Plasma Physics Reports, Journal Name: Plasma Physics Reports Journal Issue: 12 Vol. 33; ISSN PPHREM; ISSN 1063-780X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CURRENTS
DISTANCE
ELECTRIC POTENTIAL
ELECTRODES
ELECTRONS
EXCITATION
HELIUM
METASTABLE STATES
NITROGEN
PERIODICITY
PHOTOEMISSION
POSITIVE COLUMN
RADIOWAVE RADIATION