A semi-quantitative model for the deposition rate in non-reactive high power pulsed magnetron sputtering

Abstract

A theoretical treatment of the deposition process in a non-reactive high power pulsed magnetron sputtering discharge is presented. This leads to the development of a semi-quantitative model that describes the deposition rate as a function of process parameters, such as the target voltage, the peak target current density, the pulse frequency and the pulse duty cycle. The effect of these parameters on the deposition rate is studied experimentally using carbon, chromium and copper targets. The implementation of the model on the experimental results enables the estimation of the relative fractions of the sputtering gas ions (Ar+) and the sputtered metal ions (M+) in the total ion flux at the target. The M+ content in the target ion current is calculated to adopt values up to ∼72% and ∼98% for the chromium and the copper targets, respectively. In contrast, the target ion current is found to consist mostly of Ar+ species in the case of the carbon target. The significantly higher fractions of M+ ions for chromium and copper are attributed to their higher ionization probability and their higher sputtering yield in comparison with carbon.