Unraveling the Wake-Up Mechanism in Ultrathin Ferroelectric Hf $_{\text{0}.\text{5}}$ Zr $_{\text{0}.\text{5}}$ O $_{\text{2}}$ : Interfacial Layer Soft Breakdown and Physical Modeling

This article proposes a new mechanism, referred to as interfacial-layer soft breakdown (IL-SBD), to elucidate the intricate wake-up process in the ultrathin ferroelectric (FE) hafnium–zirconium oxide (HZO). Our study provides a comprehensive interpretation and compelling experimental evidence, highlighting the crucial role of the interfacial layer (IL) and its soft breakdown in the wake-up phenomenon. A multidomain FE wake-up model is developed, incorporating defect generation, trap-assisted tunneling (TAT) within the IL, and charge screening at the IL/HZO interface, validating the proposed mechanism. The model accurately reproduces the trend of thickness-dependent wake-up behavior and reveals additional variability induced by the wake-up process, emphasizing the utmost significance of minimizing the IL in ultrathin HZO devices.