Synergistic enhancement effect between external electric and magnetic fields during high power impulse magnetron sputtering discharge

As a newly emerging high ionization physical vapor deposition method, high power impulse magnetron sputtering (HIPIMS) has wide and promising prospects. Besides, the low efficiency of electron utilization and the ionization rate of the metallic particles still require to be further improved when utilized in practical industry applications. In the present work, a novel HIPIMS discharge mode that being enhanced synergistically by both the electric and magnetic fields were proposed. The synergistic enhancement discharge effect was investigated through a current sensor, plasma emission spectrometry, and higher electron utilization efficiency and sputtering particle ionization rates were obtained. The results demonstrated that, the application of external magnetic field significantly constrained the plasma and enhanced the uni-directionality. The target discharge current decreases remarkably under constant target pulse conditions, whereas the ion current collected by the substrates increases remarkably. This means that more ions participated in the film deposition process, and the number of absorbed ions and lost ions reduce significantly with the low electric potential and the scattering, respectively. The introduction of the external auxiliary anode changed the electric field and electric potential distribution in the discharging zone, which enhanced the discharging intensity, whereas the density and charge state of plasma in the system increased substantially. When the electric and magnetic fields are present at the same time, a synergistic enhancement effect occurs and interaction enhancement and the plasma density is significantly increased in all positions, which is approximately 5 times the conventional HIPIMS under charging.