Corundum-Structured AlCrNbTi Oxide Film Grown Using High-Energy Early-Arriving Ion Irradiation in High-Power Impulse Magnetron Sputtering

Abstract

A long-standing challenge in thin-film growth of oxides is low-temperature growth of the thermodynamically stable α polymorph of aluminum-based oxides with the corundum (Rc) structure. In this study, the growth of a corundum-structured multicomponent AlCrNbTi oxide film at 500 °C is achieved with the assistance of high-energy irradiation of early-arriving ions at the substrate. The acceleration of early-arriving ions is accomplished by using a high-power impulse magnetron sputtering (HiPIMS) discharge, accompanied by a synchronized substrate bias (Usync). By increasing the magnitude of Usync from -100 V to -500 V, the film structure changes from amorphous to corundum, followed by the formation of a high number-density of stacking faults or nanotwins at Usync = -500 V. This approach paves the way to tailor the high-temperature-phase and defect formation of oxide films at low growth temperature, with prospects for use in protective coating and dielectric applications.

Keywords: High-entropy oxides, HiPIMS, ion bombardment, corundum structure, nanotwin