*Bocong Zheng¹, Yangyang Fu², Keliang Wang¹, Thomas Schuelke¹, Qi Hua Fan^2
1Fraunhofer USA Center Midwest, East Lansing, MI; ²Michigan State University, East Lansing, MI
We demonstrate a self-consistent and complete description of discharge characteristics in high power impulse magnetron sputtering (HiPIMS) discharges via fully kinetic 1d3v particle-in-cell/Monte Carlo collision (PIC/MCC) electrostatic simulations. The interplay between the fundamental plasma parameters is analyzed through their spatiotemporal dynamics. Compared to conventional DC magnetron sputtering (DCMS), HiPIMS discharges require more physical processes to be considered in their simulations, such as Coulomb collisions between charged species, sputtering winds, i.e. gas rarefaction due to momentum exchange between the sputtered species and the background gas, metal ions ionized from the sputtered species, and secondary electron emission induced by these multiply charged metal ions. Considering all the above processes, this study provides the first detailed kinetic description of HiPIMS discharge in terms of discharge runaway, electron dynamics and sputtering wind. Some important conclusions previously obtained from global models are confirmed by this ab initio kinetic simulation. During the discharge runaway, i.e., the transition from the low-current DCMS regime to the high-current HiPIMS regime, metal ions gradually replace gas ions as the dominant, and the electron energization transitions from sheath energization to Ohmic heating in the ionization region. These results are beneficial for the design and optimization of HiPIMS discharge in practical applications.