Effect of Oxygen Pressure on (BaxSr1-x)TiO3 Thin Films by Pulsed Laser Ablation

Abstract

(Bax Sr1-x )TiO3 (x=0-1.0) (BST) thin films were prepared on (111)Pt/Ti/SiO2/Si substrates by pulsed laser ablation (PLA) using an ArF excimer laser at various oxygen pressures. The film compositions agree well with those of the targets. For all the film compositions, the crystalline structure of the thin films is a single perovskite phase. The thin films prepared at 133 Pa are randomly oriented. The films preferentially oriented along the [111] direction are obtained at low oxygen pressures (6.67 and 13.3 Pa). The surface morphology of the thin films becomes rougher with increasing oxygen pressure. Moreover, this roughening is prominent with low Ba content. The excessively high oxygen pressure during PLA deposition deteriorates the crystal structure and the dielectric property of BST films. The dielectric constant of BST (x=0.6) thin film prepared at the oxygen pressure of 6.67 Pa is 800 at 1 MHz.