Electrical properties of SrBi2Ta2O9 ferroelectric thin films at low temperature

The temperature dependence of electrical properties for SrBi2Ta2O9 thin film capacitors with platinum electrodes (Pt/SBT/Pt) on silicon wafers was studied from 10 to 300 K. With a decrease in temperature from 300 to 200 K, the remanent polarization of the thin films shows about an 11% reduction from its 300 K value; however, it is reduced by about 87% reduction from its 200 K value when the temperature drops from 200 to 100 K. With a decrease to 200 K, the polarization fatigue was significant, and the capacitor shows an approximate 29% reduction in polarization from its initial value following 1010 cycles. The dielectric response and leakage current of the thin films were also studied over the same lower temperature region. These results are helpful in the understanding of the fatigue-free behavior observed in SrBi2Ta2O9 thin films at room temperature and provide additional insight into their use for ferroelectric memory applications.