Electrical properties of Sr 3 Bi 4 Ti 6 O 21 thin films

Abstract

Highly c-axis-oriented Sr 3 Bi 4 Ti 6 O 21 (SBTi) thin films were fabricated on Pt-coated Si substrates by pulsed laser deposition (PLD). The structures were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM). No peaks of SrTiO 3 (STO) could be detected in the XRD pattern, indicating the existence of the SBTi single phase. Good ferroelectric hysteresis loops of the films with Pt electrodes were obtained. With an applied field of 400 kV/cm, the measured remanent polarization (P r ) and coercive field (E c ) values were 4.1 μC/cm 2 and 75 kV/cm respectively. The films showed little fatigue after 2.22×10 9 switching cycles: the nonvolatile polarizations decreased by less than 5% of the initial values. The dielectric constant and the loss tangent of the films were measured to be 363 and 0.04 at 100 kHz. These results might be advantageous for nonvolatile ferroelectric random access memory (NVFRAM) and dynamic random access memory (DRAM).