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In this article, a phase-field polarization switching model for ferroelectric HfO 2 -based thin films considering oxygen vacancies (V₎) has been developed based on the 2-D time-dependent Ginzburg–Landau (TDGL) equation coupling with Poisson’s equation. The impacts of nonuniform V₎ distributions induced by the monolayer grains in ultra-scaled Hf 0. 5 Zr 0. 5 O 2 (HZO) films and V₎ concentrations on ferroelectric characteristics are investigated in detail by the developed model which is verified and calibrated by measurement results of HZO. Furthermore, possible mechanisms of wake-up and fatigue are revealed by the simulation with the proposed model. It is clarified that the redistribution of nonuniform V₎ in the in-plane direction leads to the transition from a pinched polarization-voltage curve to a conventional one at the early stage of wake-up, while the generation of V₎ within a ferroelectric film results in ferroelectricity enhancement and reduction in wake-up and fatigue processes, respectively.
Chen et al. (Wed,) studied this question.