Effects of post-deposition annealing on the chemical composition, microstructure, optical and mechanical properties of Y2O3 film

Abstract

Reactive magnetron sputtering is an ideal technique to deposit Y2O3 films, but the existence and transformation of the physisorbed oxygen (Oδ) caused by this method were reported to have a strong impact on the films itself. In this paper, not only the Y2O3 films but powders were prepared, then the films were annealed at different temperatures (260, 350, 500, and 650 °C) according to the thermal analysis of powders. The results showed that Oδ can be transferred as desorption when the temperature increases to 260 °C, and such transformation further changes the chemical composition and the valences of O and Y elements. The post-deposited annealing can also affect the grain morphology instead of crystalline phase. The as-deposited Y2O3 films and the films annealed at higher temperature all have a cubic polycrystal with I = 100 for the (222) reflection. However, the typical orange-peel characteristics and columnar structures were only found in the Y2O3 films below 350 °C annealing. The mentioned changes including composition and grain morphology comprehensively affect the refractive index and nano-mechanical properties of Y2O3 films. This paper will provide a precise annealing temperature to obtain Y2O3 films with low physisorbed oxygen and stable micro-structure.