A study on the wake-up effect of ferroelectric Hf0.5Zr0.5O2 films by pulse-switching measurement

Abstract

The appearance of ferroelectric (FE) and anti-ferroelectric (AFE) properties in HfO₂-based thin films is highly intriguing in terms of both the scientific context and practical application in various electronic and energy-related devices. Interestingly, these materials showed a “wake-up effect”, which refers to the increase in remanent polarization with increasing electric field cycling number before the occurrence of the fatigue effect. In this work, the wake-up effect from Hf_0.5Zr_0.5O₂ was carefully examined by the pulse-switching experiment. In the pristine state, the Hf_0.5Zr_0.5O₂ film mostly showed FE-like behavior with a small contribution from AFE-like distortion, which could be ascribed to the involvement of the AFE phase. The field cycling of only 100 cycles almost completely transformed the AFE phase into the FE phase by depinning the pinned domains. The influence of field cycling on the interfacial layer was also examined through the pulse-switching experiments.