HIGH-PRESSURE NONEQUILIBRIUM MICROWAVE PLASMA SOURCE BY USING CARBON MATERIALS

A high-pressure (10 torr similar to atmosphere) microwave plasma was g enerated in a cavity resonator by using carbon materials [reticulated vitreous carbon (RVC)]. In order to investigate the effect of external parameters, the plasma parameters were measured with both probe and o ptical methods. The results indicated that this plasma was in non-equi librium state (T-e much greater than T-g). The metastable argon atoms and thermal electrons are considered as the important elements in gene rating this plasma and they were measured by the resonant optical abso rption method and by the single probe method, respectively. The electr on saturation current with RVC was larger than without it, and the RVC temperature was estimated to be about 2400 K from the Richardson-Dush man equation. The concentration of argon metastable atoms was of the o rder of 10(10) cm(-3) and increased slightly with the argon gas flow. (C) 1997 Elsevier Science S.A.