Polarization switching and discharging behaviors in serially connected ferroelectric Pt/Pb(Zr,Ti)O₃/Pt and paraelectric capacitors

The polarization switching behavior in serially connected ferroelectric Pt/Pb(Zr,Ti)O₃/Pt and paraelectric capacitors with various capacitances was examined using transient switching current measurements. Provided that a high enough voltage to switch the ferroelectric capacitor was applied to the series capacitor, stable polarization switching was maintained before the applied voltage approached zero, irrespective of the capacitance of the paraelectric capacitor. For the series capacitor containing a small paraelectric capacitance, the voltage across the paraelectric capacitor was much higher than the coercive voltage of the PZT capacitor, which acted as a field depolarizing PZT capacitor resulting in back-switching when the applied voltage was removed. In contrast, no back-switching occurred in the series capacitor containing a sufficiently large paraelectric capacitance because the voltage across the paraelectric capacitor was smaller than the coercive voltage of the ferroelectric capacitor. The effects of the measurement set-up and their implications for various suggested applications are also discussed in detail. This result improves the understanding on the role of passive interfacial layers in metal-ferroelectric-metal capacitors.