Physical Origin of Recovable Ferroelectric Fatigue and Recovery for Doped-HfO2: Toward Endurance Immunity

We have experimentally and theoretically confirmed that the ferroelectric fatigue and recovery in doped-HfO 2 under external electric field (E ext ) is dominated by the redistribution of oxygen vacancies (V o ), rather than the charge detrapping effects. The fatigue under low E ext is mainly due to the non-uniform distribution of V o caused by migration in the in-plane direction during the polarization switching, while the recover under high E ext can be attributed to the V o uniformly redistribution. The proposed mechanism has been confirmed by 2D V o distribution characterization based on EELS, and the calculation based on first principle and the phase-field modeling. Moreover, the increased cycles of fatigue-recovery leads to enhanced V o stability and further improved endurance, which is expected to realize infinite endurance of HfO 2 -based ferroelectric.