Observation and Characterization of Recoverable Fatigue Process Under Low-Electric Field (<1.8MV/cm) in HfZrO Ferroelectric Film

It is widely believed that the fatigue process of ferroelectric HfZrO (HZO) film is a permanent damage and unrecoverable, which can be regarded as a Time Dependent Dielectric Breakdown (TDDB) process. In this work, the fatigue process of HZO film under low-electric field is found to be irrelevant to defect generation. Furthermore, this fatigued device can be recovered by higher voltage stimulus and then switch normally with lower voltage pulses. This observed recoverable fatigue process is systematically investigated by the conductance method and the first-order reversal curve (FORC) measurement and the mechanism is attributed to electron de-trapping. This observed recoverable fatigue process gives the new insights on the endurance failure mechanism of HZO film under low-electric field.