Hyper power impulse magnetron – HyPIM – glow discharge

Abstract

Glow discharges are known to be limited for running at high currents (< 0.1 A · cm−2). Magnetically enhanced plasmas could overcome this limitation, typically for the magnetron operated in pulsed mode during a few 100μs. Hence, the current density could be increased by two decades, but it still stays below 10 A · cm−2. Here we report on a long (∼1 ms) pulsed operation of magnetrons, while preserving the glow mode, for current densities exceeding at least 3 times the highest current density reported for high power pulsed magnetrons. Even if the density of energy surpasses 7 J · cm−2, no arc transition was observed. Three target materials have been successfully tested: carbon (C), molybdenum (Mo) and tungsten (W) in helium atmosphere, from 5 to 30 Pa. Two key parameters are required to reach the Hyper Power Impulse Magnetron (HyPIM) glow mode: i) the accurate control of the maximum voltage during the pulse and ii) the use of the pre-ionization. Operating conditions of HyPIM will be presented and compared to other discharges.