Sr0.8Bi2.5Ta1.2Nb0.9O9+x ferroelectric thin films prepared by two-target off-axis radio frequency magnetron sputtering

Abstract

Ferroelectric Sr0.8Bi2.5Ta1.2Nb0.9O9+x thin films on a Pt/SiO2/Si substrate were prepared by using two-target off-axis radio frequency magnetron sputtering, and their structural and electrical properties were investigated. The films crystallized with high (115) diffraction intensity at a substrate temperature of 600 degrees C, and showed columnar microstructure. The 600 degrees C sputtered films with a thickness of 440 nm exhibited remanent polarization (2P(r)) of 52 mu C/cm(2) and coercive field (2E(c)) 28 kV/cm at an applied voltage of 1.5 V. The leakage current density was about 6 X 10(-6) A/cm(2) at an electric field of 50 kV/cm. The films demonstrated fatigue free characteristics up to 1.0 X 10(10) switching cycles under a 3 V bipolar 1 MHz square wave. (C) 1998 American Institute of Physics. [S0003-6951(98)04014-5].