Frequency Dependence of P-E Hysteresis Curves in PZT Thin Films

摘要

Domain switching behavior of sol-gel derived PZT thin films at high frequencies has been investigated for ferroelectric memory applications by measuring P-E hysteresis curves as a function of frequency. The coercive field (E_c) of the PZT thin films strongly depended on the measuring frequency, nevertheless their remanent polarization was almost independent of it. The domain switching kinetics of PZT thin films could be explained by the nucleation-controlled model. A linear relation was obtained between ln f and 1/E_c~2, where f is a frequency. The slope of the line changed with temperature and the interception at 1/E_c~2=0 changed with the electrode size. A guideline to make FeRAMs with a high operating speed was proposed.