Mode Jumps and Hysteresis in Surface-Wave Sustained Microwave Discharges

Various electromagnetic surface modes along a finite area dielectric interface can sustain large area overdense plasmas. Mode jumps between these modes have been reported when changing the gas pressure. In this paper we report similar mode jumps caused by changing the wave power at fixed gas pressure. A simple theoretical analysis is proposed to explain this phenomenon on the basis of the resonance behavior of the chamber impedance and a stability criterion is formulated. The theory predicts a hysteresis in the power-density dependence, which was also observed experimentally.