Growth Window of Ferroelectric Epitaxial Hf0.5Zr0.5O2 Thin Films

Abstract

The metastable orthorhombic phase of hafnia is generally obtained in polycrystalline films, whereas in epitaxial films, its formation has been much less investigated. We have grown Hf0.5Zr0.5O2 films by pulsed laser deposition, and the growth window (temperature and oxygen pressure during deposition and film thickness) for epitaxial stabilization of the ferroelectric phase is mapped. The remnant ferroelectric polarization, up to around 24 uC/cm2, depends on the amount of orthorhombic phase and interplanar spacing and increases with temperature and pressure for a fixed film thickness. The leakage current decreases with an increase in thickness or temperature, or when decreasing oxygen pressure. The coercive electric field (EC) depends on thickness (t) according to the coercive electric field (Ec) - thickness (t)-2/3 scaling, which is observed for the first time in ferroelectric hafnia, and the scaling extends to thicknesses down to around 5 nm. The proven ability to tailor the functional properties of high-quality epitaxial ferroelectric Hf0.5Zr0.5O2 films paves the way toward understanding their ferroelectric properties and prototyping devices.

References in corpus (2)

• Suppressed dependence of polarization on epitaxial strain in highly polar ferroelectrics
• Epitaxial Integration on Si(001) of Ferroelectric Hf0.5Zr0.5O2 Capacitors with High Retention and Endurance

Cited by in corpus (18)

• Intrinsic ferroelectricity in Y-doped HfO2 thin films
• Epitaxial Ferroelectric HfO2 Films: Growth, Properties, and Devices
• High polarization, endurance and retention in sub-5 nm Hf${}_{0.5}$Zr${}_{0.5}$O${}_2$ films
• Domain Matching Epitaxy of Ferroelectric Hf0.5Zr0.5O2(111) on La2/3Sr1/3MnO3(001)
• Stabilization of competing ferroelectric phases of HfO${}_2$ under epitaxial strain
• Enhanced ferroelectricity in epitaxial Hf0.5Zr0.5O2 thin films integrated with Si(001) using SrTiO3 templates
• Epitaxial Ferroelectric La-doped Hf0.5Zr0.5O2 Thin Films
• Guidelines for the stabilization of a polar rhombohedral phase in epitaxial Hf0.5Zr0.5O2 thin films
• Polarization and resistive switching in epitaxial 2 nm Hf${}_{0.5}$Zr${}_{0.5}$O${}_2$ tunnel junctions
• Blocking of conducting channels widens window for ferroelectric resistive switching in interface-engineered Hf0.5Zr0.5O2 tunnel devices
• Unraveling ferroelectric polarization and ionic contributions to electroresistance in epitaxial Hf0.5Zr0.5O2 tunnel junctions
• Critical Effect of Bottom Electrode on Ferroelectricity of Epitaxial Hf0.5Zr0.5O2 Thin Films
• Fatigue and retention in the growth window of ferroelectric Hf0.5Zr0.5O2 thin films
• Disentangling stress and strain effects in ferroelectric HfO2
• Origin of Interstitial Doping Induced Coercive Field Reduction in Ferroelectric Hafnia
• Theoretical lower limit of coercive field in ferroelectric hafnia
• Materials Relevant to Realizing a Field-Effect Transistor based on Spin-Orbit Torques
• Theoretical Investigation of Performance-Improved Ferroelectric Tunnel Junction Based on Trap-Assisted Tunneling