Properties of zirconium doped Sr-Bi-Ta-O thin films

Strontium bismuth tantalate (SrBi _2.2Ta ₂O ₉, SBT) thin films with 1,3, and 8% zirconium content were prepared on Pt/SiO ₂/Si substrates by chemical solution deposition using a butoxyethanol/ethylhexanoate chemistry. SIMS analysis revealed a uniform distribution of zirconium throughout the doped films. The X-ray diffraction patterns and scanning electron images indicated that the films were polycrystalline and phase pure, except for the 8% Zr composition. An additional diffraction peak, attributed to zirconium oxide, was observed in the 8% Zr thin film. In this composition, the capacitors exhibited low resistance and an absence of ferroelectricity. The measured 2Pr values at 3 V were 11.2, 3.2, and 1.7 μC/cm ² for the 0, 1, and 3% Zr SBT thin films, respectively. The physical and electrical characterization data indicated that zirconium is incorporated in the SBT lattice at amounts up to 3%, but less than 8%.