Effects of sputtering pressure and post-metallization annealing on the physical properties of rf-sputtered Y2O3 films

Y2O3 thin films were prepared by rf-sputtering under various sputtering pressures at room temperature. Spectroscopic ellipsometer, X-ray diffraction and semiconductor parameter analyzer were used to characterize the studied films. The results show the crystallinity and leakage current density of the films improved with decreasing sputtering pressure. The effects of post-metallization annealing (PMA) on optical, structural and electrical properties of the films were also evaluated. It is found that PMA can significantly enhance the electrical performance of Y2O3 film, and the lowest leakage current is found to be 1.54 × 10−8 A/cm2 at 1 MV/cm for the samples treated at 350 °C for 30 min. The leakage current mechanisms were discussed as well, which reveals that space charge limited current dominates the as-deposited films while Schottky mechanism describes the PMA treated ones well.

► Both the working pressure and post-metallization annealing influence the physical properties of reactive rf-sputtered Y2O3 films significantly.
► The overall properties of Y2O3 were improved by decreasing working pressure during thin film deposition and PMA treatment afterward.
► Especially, the leakage current reduced by 3 orders of magnitude after optimal PMA condition, due to the hydrogen-induced passivation effect during the annealing.