Jena 2013 – scientific programme

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P: Fachverband Plasmaphysik

P 7: Niedertemperaturplasmen I

P 7.6: Talk

Tuesday, February 26, 2013, 18:00–18:15, HS 3

The effect of structured electrodes on the electron heating in capacitively coupled radio frequency plasmas — •Nico Schmidt¹, Julian Schulze¹, Edmund Schüngel¹, Jan Trieschmann², Thomas Mussenbrock², and Uwe Czarnetzki¹ — ¹Lehrstuhl für Plasma- und Atomphysik, Ruhr-Universität Bochum — ²Lehrstuhl für theoretische Elektrotechnik, Ruhr-Universität Bochum

We investigate the effect of structured electrodes with different surface topologies on the electron heating dynamics in low pressure capacitively coupled radio frequency plasmas by a synergistic combination of experiments and numerical simulations. Linear trenches are formed between two metal blocks on the powered electrode. Various trench cross sections are realized, e.g. rectangular or triangular. The discharge is operated in the GEC reference cell with an excitation frequency of 13.56MHz. Neon is utilized for its favourable spectroscopic properties. 2D phase resolved optical emission spectroscopy with the line of sight along these trench-like structures is applied to gain lateral acces to the dynamics of highly energetic electrons. The plasma density is measured radially resolved above the structured electrode. We find that the plasma density is significantly enhanced by the presence of structured electrodes due to (i) a cross-firing of energetic electron beams due to sheath expansion from tilted surfaces and (ii) electron confinement inside the structures. This fundamental understanding is used to design specific radial-symmetric electrode topologies yielding a radially homogeneous plasma density at specific heights above the electrode via its effects on the electron heating dynamics.