Theoretical investigation of a miniature microwave driven plasma jet

M. Klute1, H.-E. Porteanu2, I. Stefanovic3, W. Heinrich2, P. Awakowicz3 and R.P. Brinkmann1

Published in:

Plasma Sources Sci. Technol., vol. 29, no. 06, pp. 065018, DOI: 10.1088/1361-6595/ab9483 (2020).

Copyright © 2020 The Author(s). Published by IOP Publishing Ltd. Printed in the UK.
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Abstract:

Radio frequency driven plasma jets are compact plasma sources which are used in many advanced fields such as surface engineering or biomedicine. The MMWICP (miniature micro wave ICP) is a particular variant of that device class. Unlike other plasma jets which employ capacitive coupling, the MMWICP uses the induction principle. The jet is integrated into a miniature cavity structure which realizes an LC-resonator with a high quality factor. When excited at its resonance frequency, the resonator develops a high internal current which - transferred to the plasma via induction - provides an efficient source of RF power. This work presents a theoretical model of the MMWICP. The possible operation points of the device are analyzed. Two different regimes can be identified, the capacitive E-mode with a plasma density of ηe≈5×1017m-3, and the inductive H-mode with densities of ηe≥1019m-3. The E to H transition shows a pronounced hysteresis behavior.

1 Theoretical Electrical Engineering, Ruhr University Bochum, Germany
2 Microwave Department, Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Berlin, Germany
3 Electrical Engineering and Plasma Technology, Ruhr University Bochum, Germany

Keywords:

plasma jet, inductively, microwave, miniature, ICP, RF