Application of positive pulse to extract ions from HiPIMS ionization region

High power impulse magnetron sputtering (HiPIMS) is a promising physical vapor deposition technique with one of the main drawbacks being its relatively low deposition rate. In this article, a method was propose by using a positive ions extraction pulse (U_extract) which would be immediately applied to the sputtering target after the HiPIMS negative pulse to extract out the ions from the ionization region near the HiPIMS target. The Particle-In-Cell/Monte Carlo Collision (PIC-MCC) simulation, experiments, and theoretical study were conducted to investigate the ions extraction process. It is demonstrated that the higher potential moved from the target area to the substrate direction and the peak ion density was driven to the substrate direction, after applying the positive ions extraction pulse to the target. The measured ion-energy distribution function (IEDF) characteristics verified that the ions extraction method works. The experimental results indicated that the Ti ⁺ ion flux dramatically increased when the U_extract was over 50 V. Good agreement between the experimental and simulation results was obtained, validating the simulation conclusion. Finally, the microscopic mechanism of ions extraction is proposed.