Effect of Duty Cycle and Frequency on the Ion Current Density on Substrate and Ion/Atom Ratio in Magnetron Sputtering of Aluminum

The paper presents the results of a study of the influence of the pulse frequency and duty cycle on the Al deposition rate, the ion current density, the ion/atom ratio and the thermal flux on a substrate during the pulsed magnetron sputtering process. Experiments were performed over a wide range of pulse frequencies (1÷200 kHz), duty cycle (5÷50%) and peak discharge power (1÷63 kW) at a constant average discharge power of 1 kW. Results were compared with DC mode of sputtering. It was found that for each duty cycle, there is an optimal pulse frequency at which the ion current on a substrate is maximum. Adjusting the pulses parameters allows increasing the density of the ion current several times. It was found that there is an optimal pulse frequency for each duty cycle value, at which the ion current on a substrate is maximum. Adjusting the pulses parameters allows increasing the ion current density on a substrate several times. A decrease in the deposition rate with a decrease of duty cycle causes a sharp increase in the ion/atom ratio, as well as in the specific energy per deposited atom. It is shown that the total thermal flux on a substrate weakly depends on the sputtering mode.