Frequency dependence of the capacitive excitation of plasma: An experimental proof
J. Appl. Phys., vol. 127, no. 18, pp. 183301, doi:10.1063/5.0005045 (2020).
Copyright © 2020 Author(s). Published under license by AIP Publishing.
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Today, most of the microwave plasma sources are driven at 2.45 GHz. Meanwhile, GaN technology offers high-power components working efficiently at higher frequencies. Therefore, the perspective of plasma excitation at increased frequencies has to be investigated. The present work compares two plasma sources fabricated in the same way, having the same size discharge zone, however, different lengths in order to resonate at 2.45 GHz and 5.8 GHz, respectively. We conclude that, at the higher frequency, for the same absorbed microwave power, the electron density is almost two times higher. This evidence comes from microwave impedance analysis, optical emission intensities, and current voltage measurement on the effluent plasma jet.
Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, 12489 Berlin, Germany
Plasma sources, Emission spectroscopy, Plasma properties and parameters, Electrical conductivity, Plasma discharges