Synergistic design of interfacial conditions and textured Pt electrodes for enhanced ferroelectricity in ZrO2 ultrathin films
Journal
Acta Materialia
Journal Volume
296
Start Page
121215
ISSN
1359-6454
Date Issued
2025-09
Author(s)
Abstract
The synergistic effects of Pt electrode crystallographic orientation and a 1-nm HfO2 interfacial layer on the ferroelectric behavior of 13-nm ZrO2 ultrathin films were investigated. The introduction of the HfO2 interfacial layer between the ZrO2 ultrathin film and textured Pt electrode significantly influenced phase stabilization by easing compressive stress and favoring the ferroelectric Pca21 orthorhombic (O) phase over the P42/nmc tetragonal (T) while still effectively suppressing the P21/c monoclinic (M) phases. Quantitative analysis revealed that the O-phase, with a fully-relaxed unit cell volume of ∼134.9 Å3, was energetically favored under moderate compression down to 128.4 Å3, in contrast to the T-phase, which stabilized at smaller volumes (<128.4 Å3). The enhanced ferroelectricity and dielectric performance of the ZrO2 ultrathin film on the (200)-textured Pt electrode (compared to the (111)-textured Pt electrode) were attributed to the synergy of the HfO2 interfacial layer and (200)-textured Pt, which provided controlled confinement and promoted a higher concentration of oxygen vacancies (VO), confirmed by elemental depth profiling from angle-resolved X-ray photoelectron spectroscopy and first-principles calculations. Theoretical insights revealed that VO, particularly at fourfold-coordinated oxygen sites, stabilizes the ferroelectric O-phase. This study leveraged interfacial design and crystallographic orientation of Pt electrodes to optimize ferroelectricity in ZrO2 ultrathin films, advancing applications in nanoelectronics and semiconductor devices.l
Subjects
Crystallographic orientation
Ferroelectricity
Interfaces
Thin films
Zirconia
Publisher
Elsevier BV
Type
journal article