Ferroelectric behaviors of W-doped SrBi 2Ta 2O 9 thin films

Abstract

W-doped SrBi 2Ta 2O 9 (SBTW) thin films were deposited on Pt/Ti/SiO 2/Si substrates by off-axis magnetron sputtering of SrBi 2Ta 1.8W 0.2O 9. Annealing at 750°C in air led to a predominant (115) orientation, coupled with a dense surface morphology. The films demonstrated well-defined hysteresis loops, with a remanent polarization (2P r) of 12.6 μC/cm 2 and coercive field (2E c) of 137.5 kV/cm. A dielectric constant of 382 and a dielectric loss of 8% were measured for the SBTW thin films at 1.0 MHz. These ferroelectric and dielectric properties are much improved on those of SBT, by considering the fact that substitution of Ta 5+ by W 6+ can suppress oxygen vacancies in the layered perovskite lattice.