Greifswald 2024 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 6: Poster I
P 6.16: Poster
Montag, 26. Februar 2024, 16:30–18:30, ELP 6: Foyer
Langmuir probe measurements in a dual-frequency capacitively coupled rf discharge — •Viktor Schneider1, Jessica Schleitzer1, Ihor Korolov2, Gerrit Hübner2, Peter Hartmann3, Julian Schulze2, and Holger Kersten1 — 1Institute of Experimental and Applied Physics (IEAP), Kiel University — 2Chair of Applied Electrodynamics and Plasma Technology, Faculty of Electrical Engineering and Information Sciences, Ruhr University, Bochum, Germany — 3Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungary
A dual-frequency capacitively coupled rf argon plasma has been investigated using a passively compensated Langmuir probe. The discharge is driven by two different excitation frequencies (13.56 MHz and 27.12 MHz) simultaneously with variable phase angle θ between them, utilizing the electrical asymmetry effect (EAE). With a passively compensated Langmuir probe the floating potential, plasma potential, electron temperature and electron density are measured for different phase angles in two different geometrically asymmetric discharges. Similar to the dc self-bias, the plasma parameters show a pronounced dependence on the phase. However, the measured profiles of the density and temperature as a function of phase in both experimental setups are not symmetric around θ = 90∘, unlike the dc self-bias. This observation is confirmed by PIC/MCC simulations, which reveal asymmetrical electron excitation/ionization dynamics at the corresponding phases. This implies that the observed trends are a property of the 2f discharge in combination with a geometric asymmetry of the discharge.
Keywords: plasma diagnostics; radio frequency discharges; plasma sheath; phase variation; Langmuir probe