Preparation of SrBi2Ta2O9 Thin Films Consisting of Uniform Grains at Low Temperature by Metalorganic Chemical Vapor Deposition

Abstract

SrBi2Ta2O9 (SBT) thin films were deposited onto (111)Ir/TiO2/SiO2/Si substrates at 570°C by electron-cyclotron-resonance plasma-enhanced metalorganic chemical vapor deposition (ECR-MOCVD). The low-oxygen-pressure condition during the ECR-MOCVD process reduced the degree of oxidation of the Ir top surface before commencement of the SBT film formation. The deposited films exhibited a (103) single orientation due to the local epitaxial growth on the (111)-oriented Ir grains. The leakage current density of the film was on the order of 10-7 A/cm2 up to an applied electric field of 380 kV/cm. Twice the remanent polarization was 16.1 µC/cm2 at an applied electric field of 360 kV/cm which was 88% of the expected value. This SBT film consisted of grains of uniform shape and had a smooth surface and good uniformity on a piezoresponse image. These results show that these films consisted of uniform grains with respect to piezoresponse and orientation, and are suitable for high-density memory applications.