Influence of deposition pressure and rf power on the structure and electrical properties of Zr0.8Sn0.2TiO4 thin films prepared by rf magnetron sputtering

Abstract

ZnO-doped Zr0.8Sn0.2TiO4 (ZST) films deposited on n-type Si (100) substrates at different deposition pressures and rf powers were investigated. The structural and morphological characteristics analyzed by x-ray diffraction (XRD), atomic force microscopy, and scanning electron microscopy were found to be affected by deposition conditions, such as deposition pressure (2, 5, and 8mTorr) and rf power (250, 350, and 450W). Highly oriented ZST (101) and (111) perpendicular to the substrate surface were identified at a deposition pressure of 8mTorr and rf power of 450W. The XRD showed that the deposited films exhibited a polycrystalline microstructure. The grain size of the film increased with increasing rf power. From observing the surface morphology, ZST thin films exhibit a columnar structure. The electrical properties were measured using capacitance-voltage and current-voltage measurements on metal-insulator-semiconductor capacitor structures. The leakage current decreased with increasing rf power and deposition pressure. As rf power=450W and deposition pressure=8mTorr, a leakage-current density of 2.26×10−9A∕cm2 was obtained at 5V.