Understanding Frequency-Dependent Accelerated Degradation Mechanisms in HfO 2 -Based 3-D Trench FeRAM

In this work, the frequency-dependent accelerated degradations (FDADs) mechanism in the novel 3-D trench hafnium oxide (HfO2)-based ferroelectric random access memory (FeRAM) has been comprehensively analyzed. The increased delay time (${t}_{\text {d}}$) between bipolar switching pulses is found to intensify remanent polarization (${P}_{\text {r}}$) degradation and induce shifts in the coercive electric field (${E}_{\text {c}}$). As the stress voltage decreases from 2.5 to 1.5 V, the${P}_{\text {r}}$degradation is exacerbated, attributed to insufficient wake-up, while the${E}_{\text {c}}$shift is correspondingly reduced, attributed to the mitigated imprint. Besides, the pulse operation method with a balanced${t}_{\text {d}}$effectively suppresses the FDAD effect. Based on the experimental observations, the mechanism of the FDAD can be attributed to the combined action of bipolar-cycling induced oxygen-vacancy (VO) generation, delay-time-dominated VOredistribution, and V${}_{\text {O}}^{{2}+}$related dipole pinning and imprint effects arising from electron de-trapping. Finally, a guideline for the FDAD recovery strategy is proposed for device optimization.