Effects of growth conditions and RF plasma on crystalline and electrical properties of SrBi2Ta2O9 thin films grown by liquid delivery MOCVD using a double alcoholate

Abstract

SrBi2Ta2O9 (SBT) thin films were prepared by liquid delivery MOCVD using a double alcoholate, Sr[Ta(OC2H5)6]2. In order to crystallize the deposited films, annealing in low pressure plasma produced by RF power was conducted as well as furnace annealing in O2 atmosphere. It was found that the Sr/Ta and Bi/Ta ratios in the deposited-films approached to the stoichiometric ratio as both deposition temperature and reactor pressure were lowered. An SBT thin film which was deposited at 400°C under 1 Torr and subsequently annealed in O2 atmosphere at 750°C for 30 min showed relatively good ferroelectricity. Remanent polarization (Pr) and coercive field (Ec) of the film were 2.0 μC/cm2 and 45 kV/cm, respectively. It was also ascertained that SBT thin films were crystallized at 650°C by annealing in oxygen plasma and showed ferroelectricity. Pr and EC of the SBT film which was annealed at 650°C in oxygen plasma with RF power of 150 W and pressure of 5 Torr were 1.5 μC/cm2 and 45 kV/cm, respectively.