Imprint mechanism in integrated Bi-rich SrBi2Ta2O9 capacitors: Influence of the temperature-dependent polarization.

In this work, we characterize the imprint properties of three-dimensional Sr0.8Bi2.2Ta2O9 (SBT) ferroelectric capacitors integrated in 0.18 μm technology using metal-organic chemical vapor deposition of SBT. We investigated the dependence of hysteresis loops on the storage temperature and duration after poling the capacitors. Also, the influence of unipolar and bipolar voltage cyclings, respectively, during and after the imprint stress was studied. We show that the imprint-induced shift of the hysteresis is limited for all the investigated stress conditions, and we associate this low shift mainly to a pronounced polarization decrease with the temperature, deviating from the Landau-Devonshire law. Our results also suggest that emission within the SBT layer is dominant over injection from the electrode in the imprint mechanism at 0 V bias. On the other hand, dynamic imprint stress results suggest an increased contribution of carrier injection. Regarding the switchable polarization, it was observed to be higher after an imprint stress due to a wake-up of ferroelectric domains, which may be thermally driven but was evidenced to be prominently field driven. The wake-up and the imprint are discussed in terms of trapping/detrapping mechanisms. [ABSTRACT FROM AUTHOR]