Fatigue-free ferroelectricity in Hf0.5Zr0.5O2 ultrathin films via interfacial design

TL;DR

This study demonstrates a novel interface design in Hf0.5Zr0.5O2 ferroelectric films that achieves fatigue-free operation exceeding 10^11 cycles, addressing reliability issues for memory device applications.

Contribution

The paper introduces a coherent CeO2-x/Hf0.5Zr0.5O2 heterointerface and symmetric capacitor architecture that together suppress fatigue and improve endurance in ferroelectric devices.

Findings

Achieved fatigue-free ferroelectric switching over 10^11 cycles.

Enhanced endurance lifetime surpassing 10^12 cycles.

Maintained temperature stability and retention in devices.

Abstract

Due to traits of CMOS compatibility and scalability, HfO2-based ferroelectrics are promising candidates for next-generation memory devices. However, their commercialization has been greatly hindered by reliability issues, with fatigue being a major impediment. We report the fatigue-free behavior in interface-designed Hf0.5Zr0.5O2-based heterostructures. A coherent CeO2-x/Hf0.5Zr0.5O2 heterointerface is constructed, wherein CeO2-x acts as an oxygen sponge, capable of reversibly accepting and releasing oxygen vacancies. This design effectively alleviates defect aggregation at the electrode-ferroelectric interface, enabling improved switching characteristics. Further, a symmetric capacitor architecture is designed to minimize the imprint, thereby suppressing the cycling-induced oriented defect drift. The two-pronged technique mitigates oxygen-voltammetry-generated chemical/energy fluctuations, suppressing the formation of paraelectric phase and polarization degradation. The design ensures a fatigue-free feature exceeding 10^11 switching cycles and an endurance lifetime surpassing 10^12 cycles for Hf0.5Zr0.5O2-based capacitors, along with excellent temperature stability and retention. These findings pave the way for developing ultra-stable hafnia-based ferroelectric devices.