Hannover 2010 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 8: Poster: Low Temperature Plasmas I

P 8.19: Poster

Dienstag, 9. März 2010, 16:00–18:00, Lichthof

Charge dynamics in electrically asymmetric dual frequency capacitive RF discharges — •Julian Schulze¹, Edmund Schüngel¹, Zoltan Donko², and Uwe Czarnetzki¹ — ¹Institute for Plasma and Atomic Physics, Ruhr-University Bochum — ²Hungarian Academy of Science

Charge dynamics in electrically asymmetric, geometrically symmetric dual frequency capacitively coupled RF discharges operated at 13.56 MHz and 27.12 MHz with variable phase shift θ between the driving voltage waveforms is investigated by a PIC simulation and analytical models. Via the Electrical Asymmetry Effect (EAE) a variable DC self-bias is generated as a function of θ. A small phase shift between the DC self bias resulting from the PIC simulation and from a fluid simulation as well as the analytical model of the EAE is found. This Small Angle Effect is explained by the charge dynamics of ions and electrons within the RF period, which is not included in either the fluid simulation or the analytical model. Finally, the electron current dynamics is investigated by the analytical model of the EAE and the PIC simulation. An analysis of the current dynamics shows that the power dissipated to electrons within on low frequency period remains constant independently of θ. This result explains why the ion flux remains constant and only the ion energy is changed as a function of θ by the EAE.