Transport and ionization of sputtered atoms in high-power impulse magnetron sputtering discharges

We use a non-stationary two-zone model to verify predictions of a steady-state phenomenological model (Vl ek and Burcalová) under the conditions in typical high-power impulse magnetron sputtering discharges (copper target of 50 mm diameter, argon pressure of 1 Pa, rectangular voltage pulses of 200 µs length with amplitudes from 400 to 1000 V and repetition frequency of 100 Hz). It is shown that the steady-state phenomenological model provides a reliable description of fundamental deposition parameters characterizing efficiency of magnetron sputtering and the transfer of target material ions to the substrate in these discharges with relatively long steady-state discharge regimes established during pulses. Based on the results, we recommend to lower the magnetic field strength in a magnetron system at a fixed average target power density in a pulse and thereby use a higher magnetron voltage in order to enhance the deposition rate and keep or even increase the ionized fraction of sputtered target material atoms in the flux onto the substrate.