New Low Temperature Processing of Sol-Gel SrBi₂Ta₂O₉ Thin Films

Abstract

A new low temperature processing method for preparation of SrBi 2 Ta 2 O 9 thin films is proposed. These thin films were prepared on Pt/Ta/ SiO 2 /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. The 1st annealing was performed in a 760 Torr oxygen atmosphere at 600° C for 30 min, and the 2nd annealing was performed in a 5 Torr oxygen atmosphere at 600° C for 30 min. The films were well crystallized and fine grained after the 2nd annealing. The electrical properties of the 200-nm-thick film obtained using this new processing method, i.e., the remanent polarization ( P r ), coercive field ( E c ), and leakage current density ( I L ), were as follows: P r =8.5 µ C/cm 2 , E c =30 kV/cm, and I L =1×10 -7 A/cm 2 (at 150 kV/cm). This new processing method is very attractive for highly integrated ferroelectric nonvolatile memory applications.