Nucleation-to-Propagation Switching Modes in Ferroelectric Hf0.5Zr0.5O2 Capacitors

Nanoscale domain nucleation and domain-wall propagation govern switching in hafnia-based ferroelectrics. However, it is not known how electrode interfaces and thermal processing govern these processes at the grain scale. Here, bias-dependent piezoresponse force microscopy and pulsed switching measurements reveal how bottom electrodes and annealing control polarization reversal in 10-nm-thick Hf0.5Zr0.5O2 capacitors. TiN promotes rapid nucleation and cross-grain propagation, NbN leads to gradual intragrain switching, and MoO2 strongly suppresses ferroelectric switching. The fastest reversal is obtained for TiN/HZO/TiN annealed at 600 °C, consistent with a fine-grained microstructure and grain boundaries that support cooperative propagation. Quantitative analysis of pulse-switching kinetics using a modified Kolmogorov-Avrami-Ishibashi framework yields comparable time constants for nucleation and growth, indicating that both processes proceed concurrently. These results establish a grain-scale mechanistic link between interfaces, microstructure, and switching kinetics in Hf0.5Zr0.5O2 capacitors.