The spatial and temporal variation of the electron energy distribution function (EEDF) in the HiPIMS discharge

Summary form only given. We describe measurements of the plasma parameters in a high power impulse magnetron sputtering (HiPIMS) discharge. A Langmuir probe is used to determine the plasma parameters, such as the effective electron temperature T_eff, the electron density n_e, the floating potential Va and the plasma potential V_pl, as well as the electron energy distribution function (EEDF). The spatial and temporal variation of the plasma parameters and the EEDF are recorded in the pressure range 3-20 mTorr. The electron density peaks at 5 x 10¹⁸ m^-3 for 40-80 mm distance from the target surface for all pressures investigated. The EEDF is more broad for lower discharge pressure. Furthermore, the EEDF becomes narrower as the pulse progresses, which indicates that the plasma cools off, probably due to increased presence of metal species in the discharge. The electron temperature reaches its peak value of 1.5-3 V at 80 microseconds after pulse initiation, in the pressure range 5-20 mTorr.