Formation of ferroelectric thin films on ruthenium electrodes

Abstract

Abstract Sr0.8Bi2.4Ta2O9 (SBT) and Bi3.25+xLa0.75Ti3O12 (BLT) films were prepared on Ru electrodes by a sol-gel spin-coating method. It was found in the case of SBT/Ru that the oxidation of Ru was suppressed by annealing at temperatures lower than 650°C in O2 atmosphere or by annealing lower than 700°C in N2. However, the remanent polarization values of the films were as low as 2.3 μC/cm2 (2Pr) for the former case and 4.4 μC/cm2 for the latter case. On the other hand, the BLT/Ru samples crystallized at 650°C showed good crystallinity without oxidation of the Ru electrode. It was found that the ferroelectric properties depended on the amount of excess-Bi sensitively, and the film prepared under the optimum Bi composition showed an excellent P-V hysteresis loop with 2 Pr of 25 μC/cm2.