LAUSR

The temporal evolutions of target voltage and current waveforms under different pulse voltage and working pressure conditions were studied during Cr high power impulse magnetron sputtering discharges. Target voltage and current characteristics demonstrated that when the pulse width was set as 200 μs, HiPIMS discharge went through a four-stage sequence during each pulse, Townsend discharge, glow discharge, afterglow, and pulse-off stages. A discharge state transition in the glow discharge stage happened at high pulse voltage and working pressure conditions. Furthermore, the dependence of reduced cathode fall thickness pdc on pulse voltage, working pressure, and normalized current density j/p2 was presented. It was found that gas rarefaction leads to a change of relationship between pdc and j/p2. A noticeable increase of the cathode fall thickness caused by gas rarefaction has been found.