Mainz 2022 – scientific programme

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P: Fachverband Plasmaphysik

P 19: Poster II

P 19.35: Poster

Thursday, March 31, 2022, 16:00–17:30, P

Control of Spokes in Magnetron Discharges — •Mathews George, Wolfgang Breilmann, Julian Held, and Achim von Keudell — Experimentalphysik II, Ruhr-University Bochum

Magnetron Sputtering is a Physical Vapour Deposition (PVD) process widely used in industry and scientific communities. Magnetron plasma appears to be homogeneous to the human eye, but shows localized zones of high brightness rotating in the ExB direction when observed with an ICCD camera with exposure times below 1µs. These local ionization zones, also called ’spokes’ are assumed to play a role in the transport of particles and energy away from the target. DCMS was chosen for the development of spoke control as an initial test object since the spokes in DC regime are more uniform compared to HiPIMS. Amplified rectangular signals are applied to two pairs of drivers to raise the plasma potential inside a spoke by drawing electron current from the plasma at the highest gradients in the ExB direction. Ion saturation current shows the responses of the spoke frequency and intensity to the applied signal. The metal ion flux from the target surface is measured time and energy resolved with a mass spectrometer. An additional probe is added to study influence of the control signal on the plasma potential inside a spoke.