Enhanced Electro‐Resistance and Tunable Asymmetric Depolarization Behavior in Hf0.5Zr0.5O2 Ferroelectric Tunnel Junction by Bottom Oxide Interfacial Layer

Abstract

AbstractElectro‐resistance (ER) plays a crucial role in the application of hafnia‐based ferroelectric tunnel junctions (FTJs), pivotal devices widely acknowledge for their potential in non‐volatile memory and neuromorphic networks. Leveraging atomic layer deposition (ALD) enhances the flexibility in fabricating bilayer FTJs by combining a ferroelectric layer with another oxide layer. Introducing additional layers is necessary to achieve a sufficient storage window for implementing intriguing functions, albeit at the risk of increased depolarization field strength. Hence, selecting a suitable inserted layer becomes paramount. In this study, a novel strategy to enhance the performance of Ge‐based Hf0.5Zr0.5O2 FTJs is presented by incorporating bottom interfacial layers (ILs) with distinct band energy characteristics. The optimized FTJs exhibit significantly improved endurance, lower coercive voltage, and enhanced retention properties. Notably, an intriguing asymmetric retention behavior driven by the imprint field (Eimp) is observed, which can be mitigated by integrating TiO2 ILs. Most importantly, an effective method to manipulate depolarization behavior in hafnia‐based devices through ILs is introduced, leading to enhanced non‐volatility and synaptic behavior in FTJs.