Düsseldorf 2007 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 22: Poster

P 22.13: Poster

Donnerstag, 22. März 2007, 16:30–18:30, Poster A

Phase and space resolved measurements of electric fields and excitation dynamics in the sheath region of a capacitively coupled radio-frequency discharge — •Julian Schulze¹, Tobias Kampschulte², Brian Heil¹, Dirk Luggenhölscher¹, Mark Bowden³, and Uwe Czarnetzki¹ — ¹Institute for Plasma and Atomic Physics, Ruhr-University Bochum — ²Institute for Applied Physics, University Bonn — ³The Open University, Milton Keynes

The electric field in the boundary sheath of discharges is a key parameter for understanding the structure and dynamics of both electrons and ions. The spatial and temporal evolution of the sheath within one RF-cycle is the cause for the generation of high energetic, directed electrons at the sheath edge, that penetrate into the plasma. These electrons are essential for ionisation and heating phenomena. Knowledge of the field allows the determination of e.g. voltages, charge densities and currents. Electric fields can be measured directly by Fluorescence-Dip Spectroscopy (FDS). Here the technique is applied for the first time to krypton as a probe gas. Measurements at different powers and pressures with high temporal and spatial resolution on a nanosecond and sub mm scale respectively are presented. Furthermore, the effect of the evolution of the sheath within one RF-cycle in terms of the excitation, caused by high energetic electrons, is investigated by Phase Resolved Optical Emission Spectroscopy (PROES). The synergistic effect of both diagnostics yields a better understanding of heating phenomena in CCRF discharges. The experimental results are compared to numerical simulation.