Impact of forming gas annealing on the fatigue characteristics of ferroelectric SrBi2Ta2O9 thin films

The metalorganic decomposition-derived SrBi2Ta2O9 (SBT) ferroelectric thin films were annealed in forming gas (5%H-2+95%N-2), and their fatigue charac teristics were investigated. Although the hysteresis loops of these films h ad an unacceptable degradation under such a H-2-containing reducing atmosph ere, no obvious polarization fatigue with electric field cycling could be o bserved. However, an increase of P*r was observed over the initial period o f the fatigue test. It could be viewed as a competition between the increas e of P*r due to the leakage current and the decrease of P*r due to switchin g polarization. H-2 played an important role in the increasing in the leaka ge current of SBT thin films, forming more weak pinning centers of domain w alls, and degradation in the fatigue characteristics. (C) 2001 American Ins titute of Physics.