New low temperature processing of sol-gel SrBi2Ta2O9 thin films

Abstract

A new low temperature processing method to prepare SrBi2Ta2O9 thin films is proposed. These thin films were prepared on Pt/Ta/SiO2/Si substrates by a sol-gel method, and their structural and electrical properties were investigated. Films were annealed before and after the top Pt electrode deposition, respectively. The 1st annealing was performed in a 760 Torr-oxygen ambient at 600°C for 30 min; the 2nd annealing was performed in a 5 Torr-oxygen ambient at 600 °C for 30 min. The films were well crystallized and fine-grained after the 2nd annealing. The electrical characteristics of the 200-nm-thick film obtained by this new process, i.e., remanent polarization (Pr), coercive field (Ec), and the leakage current density (II), were as follows; Pr = 8.5 μC/cm2, Ec=30 kV/cm, IL=1×10−7 A/cm2 (at 3V). This new processing is very attractive for highly integrated ferroelectric nonvolatile memory applications.