Nucleation-to-Propagation Switching Modes in Ferroelectric Hf<sub>0.5</sub>Zr<sub>0.5</sub>O<sub>2</sub> Capacitors.

Buyantogtokh, Batzorig; Kim, Sheung Hun; Kim, Hoon; Cho, Byung Jin; Schroeder, Uwe; Hong, Seungbum · Nano Lett · 2026

basic_science · Level V

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Abstract

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 Hf<sub>0.5</sub>Zr<sub>0.5</sub>O<sub>2</sub> capacitors. TiN promotes rapid nucleation and cross-grain propagation, NbN leads to gradual intragrain switching, and MoO<sub>2</sub> 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 Hf<sub>0.5</sub>Zr<sub>0.5</sub>O<sub>2</sub> capacitors.