Перегляд за Автор "Martins, S."

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The effect of discharge chamber geometry on the ignition of low-pressure rf capacitive discharges
(PHYSICS OF PLASMAS, 2005-09) Lisovskiy, V.; Martins, S.; Landry, K.; Douai, D.; Booth, Jean-Paul; Cassagne, V.; Yegorenkov, V.
This paper reports measured and calculated breakdown curves in several gases of rf capacitive discharges excited at 13.56 MHz in chambers of three different geometries: parallel plates surrounded by a dielectric cylinder (“symmetric parallel plate”), parallel plates surrounded by a grounded metallic cylinder (“asymmetric parallel plate”), and parallel plates inside a much larger grounded metallic chamber (“large chamber”). The breakdown curves for the symmetric chamber have a multivalued section at low pressure. For the asymmetric chamber the breakdown curves are shifted to lower pressures and rf voltages, but the multivalued feature is still present. At higher pressures the breakdown voltages are much lower than for the symmetric geometry. For the large chamber geometry the multivalued behavior is not observed. The breakdown curves were also calculated using a numerical model based on fluid equations, giving results that are in satisfactory agreement with the measurements.
Modes of rf capacitive discharge in low-pressure sulfur hexafluoride
(JOURNAL OF PHYSICS D: APPLIED PHYSICS, 2007-11) Lisovskiy, V.; Booth, Jean-Paul; Jolly, J.; Martins, S.; Landry, K.; Douai, D.; Cassagne, V.; Yegorenkov, V.
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.