Effects of impedance matching network on α-γ mode transition in atmospheric pressure RF discharges

Abstract

Abstract In atmospheric pressure RF discharges, positive and negative feedback regions are defined based on the influence of varying the capacitance of the series capacitor in an inverted L-type impedance matching network on the fed RF power at the input port of the impedance matching network. The impact of the impedance matching network on the α-γ mode transition was investigated by adjusting the tuning series capacitor in the impedance matching network. The critical RF power, as well as the current and voltage at the α-γ mode transition, is almost independent of the impedance matching network, while the counterpart immediately after the α-γ mode transition varies remarkably. The underlying mechanism is understood in terms of different feedbacks. Positive and negative feedbacks respectively promote and suppress the increment in RF power during the α-γ mode transition.