Modes of rf capacitive discharge in low-pressure sulfur hexafluoride
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Дата
2007-11
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Номер ISSN
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Видавець
JOURNAL OF PHYSICS D: APPLIED PHYSICS
Анотація
This paper presents the results of an experimental study of rf capacitive
discharge in low-pressure SF6. The rf discharge in SF6 is shown to exist not
only in weak-current (α-) and strong-current (γ -) modes but also in a dissociative δ-mode. This δ-mode is characterized by a high degree of SF6 dissociation, high plasma density, electron temperature and active discharge current, and it is intermediate between α- and γ -modes. The δ-mode
appears due to a sharp increase in the dissociation rate of SF6 molecules via
electron impact starting after a certain threshold value of rf voltage. At the
same time the threshold ionization energy of SFx (x = 1–5) radicals formed is below the ionization potential of SF6 molecules. The double layer existing in the anode phase of the near-electrode sheath is shown to play an
important role in sustaining the α- mode as well as the δ-mode but it is not a cause of the rf discharge transition from α- to δ-mode.
Опис
Ключові слова
plasma physics, gas discharges
Бібліографічний опис
J. Phys. D: Appl. Phys. 40 (2007) 6989–6999