Current gain of a pulsed DC discharge in low-pressure gases

Current and voltage waveforms of a pulsed discharge have been measured in a wide frequency range (20-300 kHz) for the two pressure values of 0.1 and 1 Torr using four different technology-relevant gases: nitrogen, oxygen, carbon tetrafluoride and sulfur hexafluoride. It is shown that the current can be substantially increased in the pulsed dc discharge, especially with electronegative gases, as compared with the discharge current relating to the same but constant voltage. The maximum 9-fold current gain is obtained with sulfur hexafluoride. Carbon tetrafluoride furnishes up to 4-fold amplification, while nitrogen and oxygen show the typical current gain of 1-2. Physical mechanism of this phenomenon is discussed.