Ferroelastic Domain Switching and Time-Resolved Negative Capacitance in Polar-Axis-Oriented Hf0.5Zr0.5O2 Grown by Atomic Layer Epitaxy
Journal
Small
ISSN
1613-6810
1613-6829
Date Issued
2024
Author(s)
Yu‐Sen Jiang
Wei‐En Lin
Makoto Shiojiri
Yu‐Tung Yin
Yu‐Cheng Su
Chih‐Hung Nien
Chen‐Feng Hsu
Vincent Duen‐Huei Hou
Chih‐Sheng Chang
Iuliana Radu
DOI
10.1002/smll.202408278
Abstract
Ferroelectric properties of Hf0.5Zr0.5O2 are strongly correlated with its crystallographic orientation, with the [001] direction serving as the polar axis. However, the epitaxial growth of highly polar-axis-oriented Hf0.5Zr0.5O2 layers with pronounced ferroelectricity is rarely reported. Here epitaxial (001)-oriented Hf0.5Zr0.5O2 thin films grown by atomic layer epitaxy (ALE) is demonstrated, which achieve a state-of-the-art ferroelectric polarization up to 78.9 µC cm−2. The epitaxial Hf0.5Zr0.5O2 layer experiences a lattice reorientation from (010) to (001) during the wake-up process, as evidenced by plane-view precession electron diffraction. Accordingly, a two-step, 90° ferroelastic domain switching model is proposed to elucidate multiple polarization switching. Furthermore, the observed polarization switching dynamics closely match with the time-resolved negative capacitance, which is quantified as an equivalent high dielectric constant of −170. This study highlights the capability of ALE to precisely control the crystallographic orientation of Hf0.5Zr0.5O2 thin films, providing deep insights into fundamental ferroelectric mechanisms.
Subjects
atomic layer epitaxy
ferroelectric
negative capacitance
polarization switching dynamics
precession electron diffraction
Publisher
Wiley
Type
journal article