Mainz 2022 – scientific programme

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P: Fachverband Plasmaphysik

P 9: Poster I

P 9.37: Poster

Tuesday, March 29, 2022, 16:00–17:30, P

Oxygen dependent etch rates of MF-particles in an RF-plasma — •Cassedyn Wirtz, Sören Wohlfahrt, and Dietmar Block — Institute of Experimental and Applied Physics, Kiel University, Germany

Microparticles are the essential component of a complex plasma. The forces affecting these particles, as well as their accumulated charge, depend prominently on their size. Thus, a precise knowledge of the particle size is a key input for quantitative description and modelling. However, in interaction with the plasma, the size can change due to etching and surface processes. The precise knowledge of the etch rate is especially important for measurements ranging from several minutes to hours. Melamin-formaldehyde (MF) particles are widely used in complex plasmas and known for changing their size during plasma exposure. It was shown that the etch rate depends strongly on the presence of oxygen in the discharge. We use an advanced light scattering technique that uses angular- and polarization resolved light scattering (APRLS) [1], which allows to determine the particle size with high temporal resolution. Utilizing this resolution the etch rates of MF-particles dependent of the oxygen content are further investigated, with focus on the regime of low admixtures (< 10%).

[1] S. Wohlfahrt, D. Block, "High-precision in-situ measurements of size and optical properties of single microparticles in an RF-plasma", Physics of Plasmas 28, 123701 (2021)