Decoupling effects of the resistive-switching behavior on the polarization reversal in ultrathin ferroelectric Hf0.5Zr0.5O2 films

TL;DR

This study decouples resistive-switching effects from polarization reversal in ultrathin Hf0.5Zr0.5O2 ferroelectric films, revealing their impact on device performance and proposing strategies for improvement.

Contribution

It introduces a method to separate resistive-switching behavior from polarization switching in ultrathin ferroelectric HfO2-based films, enhancing understanding of their influence on device reliability.

Findings

Resistive switching inflates polarization measurements and increases coercive fields.

Symmetric electrode design reduces resistive switching activity and improves cycling endurance.

Decoupling resistive effects clarifies the true ferroelectric switching behavior.

Abstract

HfO2-based ferroelectric films have attracted considerable attention as their nanoscale ferroelectricity and compatibility with cmos technology, fulfilling demands of emerging memory technologies. However, as films scale down, resistive-switching behavior becomes increasingly pronounced, intricately intertwining with the polarization-switching process and affecting ferroelectric switching factors often overlooked yet crucial for device performance optimization. By characterizing resistive-switching behavior and oxygen vacancy motion using tailored electric pulse schemes, we decouple the resistive-switching behavior from the overall switching process in ultrathin ferroelectric HZO films, which would otherwise erroneously inflate polarization values and increase coercive fields. Building on this, we elucidate endurance degradation mechanisms from dual perspectives of resistive switching and defect migration. Furthermore, we demonstrate the mitigated resistive switching activity by designing HfO2-based devices with symmetric oxide electrodes, achieving reduced coercive fields and improved cycling performances. This work provides crucial insights into the origins of inflated polarizations and reliability challenges in HfO2-based devices while offering a viable strategy to enhance ferroelectric properties for advanced memory applications.