VERY HIGH TUNABILITY OF BaSnxTi1-xO3 FERROELECTRIC THIN FILMS DEPOSITED BY SOL-GEL

Abstract

Ba(Sn0.02Ti0.98)O3 thin films (BTS) were prepared by sol-gel route and deposited by spin-coating on commercial Pt/Ti/SiO2/Si substrates. By modifying the annealing conditions from 750°C for 1 h to 950°C for 15 min, the grain size increased from 60 nm to 110 nm due to the increased driving force. The dielectric permittivity ε′ and tunability nr are correlated with the grain size: these parameters increase with the grain size. At room temperature for the BST film annealed at 950°C, a record value of 76% of tunability is obtained at 10 kHz. This very high value of tunability makes BaSnTiO 3 a very good candidate for tunable devices.