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P: Plasmaphysik

P 21: Plasmatechnologie (Poster)

P 21.4: Poster

Monday, March 15, 1999, 16:30–19:00, PY

Investigation on the Afterglow of a Surface Wave Sustained Discharge in Nitrogen — •D. Douai, J. Berndt, and J. Winter — Institut für Experimentalphysik II, Ruhr-Universität Bochum, 44780 Bochum

Microwave excited plasmas find an increasing number of applications in the industrial plasma processing techniques. As an example, novel methods for nanostructuring require a source of reactive neutrals which affect the surface via their excitation energy or chemical reactivity, less by their kinetic impact. The flowing post-dicharge of a Surface Wave Sustained Discharge is expected to be a promissing tool for this purpose.

In our case, the Surface Wave (2,45 GHz) is created by a Waveguide-Surfatron at rough vacuum (1 to a few tens of mbar) and propagates along the z-axis of a three media cylindrical geometry (plasma, quartz and air). The reactive species, created in the active zone of the discharge, flow into the reaction chamber at medium vacuum (10⁻³ mbar). The flowing afterglow of a Nitrogen/Argon microwave plasma is studied by means of Mass Spectrometry and Optical Spectroscopy. The Threshold Ionization Mass Spectrometry technique is used to determine the dissociation degree of the molecular Nitrogen in the post-discharge reactor. Gas temperature in the near afterglow is performed with Optical Emission Spectroscopy, whereas ICCD measurements provide a better understanding of the structure of the flowing post-discharge in the reactor.

This work is supported by the SFB 191 Teilprojekt B8.