Sr 0.8 Bi 2.5 Ta 1.2 Nb 0.9 O 9+x ferroelectric thin films prepared by two-target off-axis radio frequency magnetron sputtering

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 °C, and showed columnar microstructure. The 600 °C sputtered films with a thickness of 440 nm exhibited remanent polarization (2Pr) of 52 μC/cm2 and coercive field (2Ec) 28 kV/cm at an applied voltage of 1.5 V. The leakage current density was about 6×10−6 A/cm2 at an electric field of 50 kV/cm. The films demonstrated fatigue free characteristics up to 1.0×1010 switching cycles under a 3 V bipolar 1 MHz square wave.