Surface-Wave Plasma Sources

Abstract

The phenomenon of electromagnetic surface wave propagation along the interface between a preexisting plasma column and its surrounding dielectrics has been recognized and described in detail decades ago.1?2 Later, in the early seventies, these waves began to be used to sustain plasma columns.3,4 These so-called surface-wave discharges (SWD) exhibit many advantageous features: long, stable plasma columns can be sustained over large domains of wave frequencies (from less than 1 MHz up to approximately 10 GHz*) and gas pressures (from approximately 10−5 torr up to a few times atmospheric pressure). SWD setups are simple, compact, easy to handle and ensure an efficient energy transfer from the microwave power source to the plasma.5