Electrical Properties of Ba0.5Sr0.5Ta2O6 Thin Film Fabricated by Sol-Gel Method

Ba0.5Sr0.5Ta2O6 (BSTA) thin film was successfully fabricated on a Pt/SiO2/TiO2/Si substrate using the Sol-Gel method. Fundamental electrical properties of the BSTA thin film were investigated using metal-insulator-metal (MIM) structure. No diffusion of ions, from the thin film or the substrate, is observed because of the using of MIM structure. The Root Mean Square roughness of 1.04nm shows that thin film grew well on the substrate. The BSTA thin film shows a much higher dielectric constant of about 130 than conventional gate insulators and high-k materials that are currently used in Thin Film Transistors. Low leakage current density of about 10-8 A/cm2 was obtained at an applied electric field of 500kV/cm. Schottky emission is the dominant conduction mechanism at applied electric fields lower than 500kV/cm and Fowler-Nordheim tunneling is the dominant conduction mechanism at higher applied electric fields. The Schottky barrier height between the Pt electrode and the Ba0.5Sr0.5Ta2O6 thin film was estimated to be 0.75eV.