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.