Unified Phase-Field Framework for Antiferroelectric, Ferroelectric and Dielectric Phases: Application to HZO Thin Films

Abstract

Polycrystalline hafnia-based thin films exhibit mixed ferroelectric (FE), antiferroelectric (AFE), and dielectric (DE) behavior, with switching characteristics strongly influenced by microstructure and phase distribution. Here, we develop a unified grain-resolved three-dimensional phase-field framework for metal-insulator-metal capacitors that simultaneously captures ferroic phase characteristics in realistic polycrystalline microstructures by explicitly incorporating grain topology and crystallographic orientation. Antipolar sublattice kinetics are represented via the coupled evolution of macroscopic and staggered polarization order parameters. All thermodynamic and kinetic parameters are calibrated to experimental P-E hysteresis loops and held fixed across all simulations. The results show that phase fractions primarily determine hysteresis character, while vertical segregation of AFE- and FE-rich regions systematically reduces the effective coercive field (Ec) under identical electrical loading. Grain-resolved analysis reveals that this reduction arises from microstructure-assisted switching pathways and electrostatic coupling between layers. These findings demonstrate that vertical phase arrangement provides a viable strategy to engineer switching behavior in hafnia-based ferroic capacitors and highlight the importance of explicit microstructural resolution for quantitative phase-field modeling.