Jena 2013 – scientific programme
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P: Fachverband Plasmaphysik
P 10: Poster: Plasmadiagnostik
P 10.7: Poster
Wednesday, February 27, 2013, 16:30–18:30, Poster EG
Mode transitions in inductively coupled RF discharges. — •Thomas Wegner, Christian Küllig, and Jürgen Meichsner — Institute of Physics, University of Greifswald, 17489 Greifswald
Plasma parameters of an inductively coupled radio frequency (ICRF) discharge in argon and oxygen were measured by Gaussian beam microwave interferometry (MWI) and Langmuir probe diagnostics (LPD). The inductive coupled source consists of a planar double spiral antenna (2.75 windings, 115 mm diameter) * and a quartz cylinder. Whereby, the quartz cylinder serves as dielectric barrier and seperates additionally the antenna from the vacuum in the plasma vessel. The energy transfer into the plasma is realized by powering the center of the antenna by means of a RF power generator throug a matching network. The peak-to-peak voltage was chosen as an applicable parameter to describe the mode transition from E to H-mode by the line integrated electron density (MWI) and the ion saturation current (LPD). Thereby, the mode transition is characterized by a significant increase of the line integrated electron density up to two orders of magnitudes from 1015 to 1017 m−2 and a decrease of the peak-to-peak voltage depending on the pressure. Comparable results are achieved for the ion saturation current. First investigations regarding the hysteresis behavior show that their existence depends on pressure and matching situation.
*Cooperation with J. Schulze and U. Czarnetzki (Ruhr-University Bochum)
Funded by the DFG CRC/Transregio 24, project B5.