Influence of substrate cooling on ion conductivity of tantalum oxide thin films prepared by reactive sputtering using water vapor injection

Abstract

We studied a reactive sputtering technique that involves substrate cooling with liquid nitrogen and water vapor injection into the substrate surface to deposit Ta2O5 solid electrolyte thin films. The ion conductivities of the tantalum oxide films increased upon substrate cooling, and the maximum conductivities of approximately 10−3 S/m were obtained at substrate temperatures of −120°C and −80°C. The deposition rate increased by substrate cooling and high deposition rates of 30–50 nm/min were obtained at substrate temperatures of −80 °C to −170 °C. According to these results, this sputtering technique is highly effective for improving ion conductivity and the deposition rate of Ta2O5 films.