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P: Fachverband Plasmaphysik

P II: Poster: Niedertemperaturplasmen, Plasmatechnologie

P II.12: Poster

Tuesday, March 11, 2008, 11:00–13:00, Poster C3

Investigations on Self-excited Plasma Series Resonance — •Christopher Knier, Julian Schulze, Dirk Luggenhölscher, Kostyantyn Polozhij, and Uwe Czarnetski — Institute for Plasma and Atomic Physics, Ruhr-University Bochum

Self-excited Plasma Series Resonances (PSR) are observed in capacitively coupled discharges as high frequency oscillations superimposed on the normal RF current. The high frequency oscillations are generated by a series resonance between the capacitive sheath and the inductance and resisitivity of the bulk caused by electron inertia and elastic collisions with the background gas. The non-linearities of the sheath capacities cancel out for symmetric discharges. However, this is not the case for asymmetric discharges, leading to a very complex behaviour and increased power dissipation at low pressures.

A global model using a one-dimensional geometry has been derived. In order to realize one-dimensional discharge conditions experimentally, a cylindrical chamber with a coaxial powered electrode has been setup. Applied diagnostics include different types of current (e.g. SEERS), voltage and Langmuir probes. The measured data are compared to numerical simulations and data from non-cylindrical geometries.