The experimental approach into the influence of external inductance on the discharge characteristic of HiPIMS

The main objective of the current paper is to describe the effect of external inductance (EI) on the current discharge waveforms of HiPIMS at different pulse-on time (Pon) and its relation with static deposition rate and topographical properties of deposited titanium thin films, which is investigated by scanning electron microscope and atomic force microscope. It has shown that the higher the EI, independent of the Pon, the higher the peak power is. The delay time also extensively increases when an EI is implemented into the circuit. However, the rise time does not have a linear dependency with the EI and its behavior changes to some extent at different Pon. By increasing the EI from zero to 30 mH at Pon = 60 μs, the peak power subsequently rises from 11 to 32 kW at constant time-average power. Meanwhile, the deposition rate decreases from 8.5 to 1.5 nm/min, which is mainly attributed to the metal ions return to the target surface and nonlinear dependency of sputtering yield with applied voltage. It was also revealed that the higher peak power has no special effect on the surface roughness of titanium thin films deposited by HiPIMS.