A Physics-Based Compact Model for Ferroelectric/Antiferroelectric Mixed Phase Capacitor Incorporating Reliability Characteristics

We developed a physics-based compact model for ferroelectric/antiferroelectric (AFE) mixed-phase capacitors. The nucleation-limited switching (NLS) model is utilized to model polarization reversal dynamics for the ferroelectric phase, whereas the Pauli-Master equation, based on Kittel’s two-sublattice theory, is utilized for the AFE phase. We derive the electrostatic field in the film, precisely accounting for various extrinsic factors such as the finite screening lengths of metallic electrodes, the presence of dielectric interlayers, and charge trapping at the interfaces and borders. Consequently, the reliability model is constructed within a unified formalism by incorporating trapped charges, dielectric interlayers, and the decomposition process of ferroelectric phase nuclei. Therefore, this model illustrates essential characteristics of ferroelectric/AFE mixed-phase capacitors, encompassing the wake-up effect, accumulation effect, temperature dependence of polarization reversal, geometry dimension scalability, variability between devices, and reliability characteristics such as the fatigue effect, imprint effect, and degradation of retention properties. Furthermore, by using experimental data acquired from capacitors composed of HZO with a thickness of 8 nm, we validate the model, which exhibits a good fit with the experimental results. As a result, this model enables the efficient implementation of circuit simulations that incorporate ferroelectric nonvolatile memory.