Crystalline ZrO2 films with reduced oxygen vacancy and surface roughness for corrosion protection by atomic layer deposition

Abstract

ZrO2 coating is widely used for ensuring protection against corrosion and diffusion. Thus, a uniform coating of a high-quality film is key to protecting parts exposed to corrosive gas environments. In this study, we report optimized atomic layer deposition (ALD) process parameters to deposit crystalline ZrO2 films. Cyclopentadienyl tris(dimethylamino) zirconium (CpZr(NMe2)3) was used as the Zr precursor to obtain the crystalline characteristics of ZrO2 films by controlling the deposition temperature. A single phase of cubic ZrO2 was formed at the deposition temperature of 225–250 °C, whereas a mixed phase of monoclinic and tetragonal ZrO2 was obtained at 275–300 °C, suggesting that the tunable properties of the ZrO2 coating layer corresponded to the targeted applications. The mixture of tetragonal and monoclinic phases of the ZrO2 films exhibited the highest corrosion resistance properties due to the reduced oxygen vacancy with minimized surface roughness from the highest crystalline state of stable ZrO2 phases. Achieving superior reproducibility and uniformity enables the present low-temperature ALD to be utilized for commercial coating processes, to be readily applied to many complex-shaped parts, such as diffusers, and to provide a pathway to form a protective layer with improved performance of metals and alloy surfaces.