Crystallization of 8 mol% yttria-stabilized zirconia thin-films deposited by RF-sputtering

The crystallization upon thermal treatment of 8 mol% yttria-stabilized zirconia thin films deposited by RF-sputtering at room temperature is investigated. The as-deposited YSZ films are biphasic with crystallites of 5-10 nm in diameter building a columnar-like microstructure. Fully crystalline YSZ thin films are obtained after isothermal dwells in the temperature range 800-1100 C. X-ray diffraction and Raman spectroscopy demonstrate that the crystalline films have a cubic structure retained even after high-temperature annealing while a strong texture is developed. Further, a stagnating grain-growth is observed, characterized by a final grain size of about 60 nm and a micro-strain of 0.15%. Given the observed films' micro-structural stability, their application in miniaturized electrochemical devices such as micro-solid oxide fuel cells or sensors can be foreseen.