Synergy of experiment and model for reactive HiPIMS: effect of discharge parameters on WOx composition and deposition rate

Reactive high-power impulse magnetron sputtering of tungsten oxide films using metallic tungsten target (72 mm in diameter) in argon-oxygen atmosphere (total pressure of 0.75 Pa) was carried out. The effect of various discharge parameters on the deposition rate and film oxygen concentration was investigated. Moreover, a model combining a reactive high-power impulse magnetron sputtering model and a discharge plasma model for the ionization region was successfully used for deeper insight into the effect of particular discharge parameters such as voltage pulse length (from 100 –800 µs), oxygen partial pressure (from 0.25–0.50 Pa) or the value of pulse-averaged target power density (from 2.5–500 W cm−2). The results of the presented model, most notably trends in the target- and substrate oxide fraction, composition of particle fluxes onto the substrate, degree of W atom ionization or degree of O2 molecule dissociation are discussed and put into context with experimentally measured quantities.