Enhanced oxidation of TiO2 films prepared by high power impulse magnetron sputtering running in metallic mode

A method is introduced that allows suppressing unwanted effects of target poisoning during reactive high-power impulse magnetron sputtering (R-HiPIMS) employed for deposition of oxide films. The method, based on higher reactivity of excited/activated oxygen species, is studied and demonstrated on TiO2 films deposited in R-HiPIMS discharge running very close to the metallic mode with a high deposition rate. An external source of energetic plasma that activates oxygen gas, delivered to the vicinity of the substrate, is combined with conventional R-HiPIMS of the Ti target. The activated oxygen species enable reducing the total flow rate, which simultaneously results in suppression of the target poisoning effect. On the other hand, sufficient oxidation and growth of transparent crystalline TiO2 films were observed. Published by AIP Publishing.