SMuK 2023 – scientific programme
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P: Fachverband Plasmaphysik
P 16: Plasma Wall Interaction II/Codes and Modeling I
P 16.3: Talk
Thursday, March 23, 2023, 14:45–15:00, CHE/0091
Separation of plasma species fluxes for investigating plasma-surface interactions — •Adrian Heiler1, Roland Friedl2, and Ursel Fantz1,2 — 1Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching — 2AG Experimentelle Plasmaphysik, Universität Augsburg, 86135 Augsburg
Low pressure plasmas are commonly applied for surface treatment processes. To investigate the role of the different plasma species in the plasma-surface interaction, a selective exposure is indispensable. Therefore, the separation of plasma species fluxes from an inductively coupled plasma source (27.12 MHz, 600 W max.) is demonstrated by using magnets and a MgF2 window. The plasma source is operated in hydrogen at pressures of 4−10 Pa and is connected to a vacuum chamber in which surfaces can be installed at a sample holder. The impinging fluxes of hydrogen atoms, positive hydrogen ions and UV/VUV photons (up to 15 eV) are quantified by using optical emission spectroscopy, a Langmuir probe and a VUV diagnostic. The VUV diagnostic is based on a photodiode and optical filters for wavelength selection and is calibrated against a VUV spectrometer.
The influence of the UV/VUV photons, hydrogen atoms and positive hydrogen ions on surfaces is exemplarily demonstrated by applying work function measurements of in situ caesiated metal samples. By this, it is shown that each species can affect the surface separately. The impact of the selective exposure is compared to the full plasma-surface interaction by the generation of well-characterized inductively coupled hydrogen plasmas directly in front of the surface.