Effect of bismuth excess on the crystallization of Bi3.25La0.75Ti3O12 thin films on Pt/Ti/SiO2/Si substrates

Bismuth lanthanum titanate (BLT) thin films with excess Bi contents wore prepared onto a Pt/Ti/SiO2/Si substrate by a metalorganic decomposition technique (MOD). The effect of Bi excess on the microstructure and ferroelectric properties was investigated. When a 10% of Bi excess was added, the BLT thin films showed a polycrystalline structure. The remanent polarization and dielectric constant decreased with more than 10% of Bi excess, Bi deficiency or Bi excess over 10% in the BLT films resulted in poor fatigue properties. This was attributed to the structure defects and a presence of a secondary phase, which coexists with a layered perovskite phase. The BLT thin films with 10% of Bi excess have the remanent polarization (2P(r)) value of 25.66 muC/cm(2) and a coercive field of 84.75 kV/cm. The BLT thin films with 10% of Bi excess showed no fatigue even after 1 x 10(9) bipolar switching cycles. (C) 2004 Elsevier B.V. All rights reserved.