Characteristics of ferroelectric SrBi2Ta2O9 thin films grown by “flash” MOCVD

Abstract

A chemical vapor deposition process for the ferroelectric SrBi₂Ta₂O₉ has been developed utilizing a liquid delivery and flash vaporization technique. Uniform layered perovskite of SrBi₂Ta₂O₉ was formed over 4 inch wafers by the chemical vapor deposition followed by annealing at 800°C in oxygen ambient. The SrBi₂Ta₂O₉ thin film capacitors showed well saturated hysteresis loops with remanent polarization (2Pr) and coercive field (Ec) of up to 21.3 (μC/cm²) and 47.2 (kV/cm), respectively. The SrBi₂Ta₂O₉ capacitors with platinum electrodes showed fatigue free characteristics after switching of 1×10¹⁰ cycles. The chemical vapor deposition technique demonstrated excellent conformal coating of SrBi₂Ta₂O₉ film on 0.5 μm line-and-space patterns. These performances will meet the requirements for high-density nonvolatile memory devices.