Mechanism for slow switching effect in advanced low-voltage, high-speed Pb(Zr/sub 1-x/Ti/sub x/)O/sub 3/ ferroelectric memory

Slow-switching effect in PZT ferroelectric memory under low-voltage and high-speed operation is observed. The slow-switching effect becomes worse at lower operation voltage and elevated temperature. This effect significantly reduces the sensing margin and causes severe reliability issue for advanced ferroelectric memory, particularly for low-voltage and high-speed applications. This slow-switching effect is believed to be attributed to slowing down of polarization switching caused by band bending from Schottky built-in potential at the electrode/ferroelectric interface. The proposed mechanism is supported by the polarity dependence in an asymmetric LNO/PZT/Pt sample.