Characteristics of spin-on ferroelectric SrBi₂Ta₂O₉ thin film capacitors for ferroelectric random access memory applications

We report on the properties and characterization of SrBi₂Ta₂O₉ (SBT, or Y − 1) thin film capacitors for ferroelectric random access memory (FERAM) applications. The films were prepared by spin-coating from carboxylate precursors. The remanent polarization (P_r) was 5−6 μC/cm² and the coercive field was ∼55 kV/cm. Excellent fatigue endurance was observed up to 10¹¹ cycles. Auger analysis indicates bismuth diffusion through the Pt electrode after capacitor anneal which might require excess Bi in the precursor solution for stoichiometry control. No detectable amount of α emission was found from SBT films, which reduces the possibility of soft error when used in the memory devices.