Electrochemical control of ferroelectricity in hafnia-based ferroelectric devices using reversible oxygen migration

TL;DR

This paper demonstrates reversible electrochemical control of ferroelectricity in hafnia-based thin films through oxygen migration, enabling multiple polarization states and repair of ferroelectric damage for advanced memory applications.

Contribution

It introduces a novel electrochemical method to reversibly manipulate ferroelectricity in hafnia-based devices via oxygen vacancy engineering, with high breakdown fields and multiple polarization states.

Findings

Reversible oxygen migration controls ferroelectric polarization.

Achieved multiple stable polarization states.

Demonstrated repair of ferroelectric damage.

Abstract

Ferroelectricity, especially in hafnia-based thin films at nanosizes, has been rejuvenated in the fields of low-power, nonvolatile and Si-compatible modern memory and logic applications. Despite tremendous efforts to explore the formation of the metastable ferroelectric phase and the polarization degradation during field cycling, the ability of oxygen vacancy to exactly engineer and switch polarization remains to be elucidated. Here we report reversibly electrochemical control of ferroelectricity in Hf$_{0.5}$Zr$_{0.5}$O$_2$ (HZO) heterostructures with a mixed ionic-electronic LaSrMnO$_3$ electrode, achieving a hard breakdown field more than 18 MV/cm, over fourfold as high as that of typical HZO. The electrical extraction and insertion of oxygen into HZO is macroscopically characterized and atomically imaged in situ. Utilizing this reversible process, we achieved multiple polarization states and even repeatedly repaired the damaged ferroelectricity by reversed negative electric fields. Our study demonstrates the robust and switchable ferroelectricity in hafnia oxide distinctly associated with oxygen vacancy and opens up opportunities to recover, manipulate, and utilize rich ferroelectric functionalities for advanced ferroelectric functionality to empower the existing Si-based electronics such as multi-bit storage.