Dual Discharge Modes Operation of an Argon Plasma Generated by Commercial Electronic Ballast for Remote Plasma Removal Process

An argon plasma generated between the cone-shaped electrode powered by commercial electronic ballast and grounded plane electrode has been investigated. Since the electronic ballast has positive and negative cycle in a period, two different discharge modes of remote plasma-the normal glow discharge mode and the hollow cathode discharge mode-have been observed. It is noted that the hollow cathode discharge mode has wider operation window in gas pressure than the glow discharge one. The glow discharge started to be extinguished at pressure higher than 4.1 torr and turned to the hollow cathode discharge mode in the holes on ground plate, while the hollow cathode discharge mode kept growing until 10 torr. These results show that the stable operation window of the system could be defined by the glow discharge mode rather than the hollow cathode discharge mode and could be improved by optimizing the applied voltage waveform and electrode configuration.