Low-temperature switching fatigue behavior of ferroelectric SrBi₂Ta₂O[sub 9] thin films

Abstract

The ferroelectric hysteresis and fatigue behavior over a wide temperature range from 290 to 50 K for SrBi₂Ta₂O[sub 9] thin films with Pt electrodes on silicon substrates, prepared by metalorganic decomposition (MOD) and pulsed-laser deposition (PLD), are investigated. It is found that given a fixed electrical field amplitude, the coercivity of all films increases with decreasing temperature T. The saturated hysteresis loop easily obtained for the MOD-prepared thin films has its remnant polarization enhanced with decreasing T, but the PLD-prepared samples exhibit minor loops whose remnant polarization decays with decreasing T. While the films prepared by MOD exhibit improved fatigue resistance at low T, significant fatigue effect at low T is observed for the films prepared by PLD. Although we cannot rule out the effect of strain, the experimental results can be explained by competition between pinning and depinning of domain walls, which are dependent of temperature and defect charges.