Deposition, structure evolution and dielectric properties of BaTiO3 and BaxSr1-xTiO3 thin films prepared by the sol-gel method

BaTiO3 (BTO) and Ba1-xSrxTiO3 (BSTO) thin films (15-45 nm) were obtained with good dielectric properties on Si wafer using the sol-gel method. The films are coated with the sol solution by spin coating technique and additional thermal annealing. The results from XPS and XRD measurement show that, at high thermal annealing at 700-800degreesC, there is a penetration of the Si atoms from the substrate into the layer, forming silicon oxide. In this way, formation of solid solution BTO + SiO2 and BSTO + SiO2 takes place, leading to an improvement of the film dielectric properties: small leakage current and high breakdown voltage, but the dielectric constant decreases. (C) 2002 Elsevier Science Ltd. All rights reserved.