Preparation and properties of erbium oxide films deposited by radio frequency magnetron sputtering

Abstract The erbium oxide (Er 2 O 3 ) film is considered as a candidate for tritium permeation barrier in recent years because of its low permeation reduced ratio and easy accessibility. Erbium oxide films with different thickness were prepared by radio frequency magnetron sputtering with varying substrate temperature and sputtering time. The film surface morphology, structure, residual stress and deuterium permeation behavior were investigated. The films were compact and smooth, while the thickness varied from 200 nm to 1000 nm. The (2 2 2) preferential orientation of Er 2 O 3 depressed, when the substrate temperature above 200 °C. With the substrate temperature increasing from RT to 200 °C, the compressive stress became larger, and it converted into tensile stress deposited at 400 °C. The residual stress transformed from tensile to compressive stress as the film got thicker. The permeation flux of the sample deposited with Er 2 O 3 film was 2 orders of magnitude less than that of uncoated one. The permeation reduced factor (PRF) of 0.5-μm Er 2 O 3 film deposited at room temperature is about 300 at 773 K.