Low Temperature Growth of Sol-Gel SrBi₂Ta₂O₉ Thin Films by Low Pressure Annealing

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 760Torr-oxygen ambient at 600°C for 30min., the 2nd annealing was performed in a 5Torr-oxygen ambient at 600°C for 30min.. The films were well crystallized and fine-grained after the 2nd annealing. The electrical characteristics of the 200-nm-thich film obtained by this new process, i.e., remanent polarization (Pr), coercive field (Ec), and the leakage current density (I_L), were as follows; Pr=8.5μC/cm², Ec=36kV/cm, I_L =1×10^-7A/cm² (at 150kV/cm). This process is very attractive for highly integrated ferroelectric nonvolatile memory applications.