Unveiling the Role of Local Stress in Enhancing Ferroelectric Properties and Endurance of HfO₂/ZrO₂ Superlattice Structures

Abstract

Ferroelectric superlattices (SL) composed of HfO2 and ZrO2 have garnered significant interest due to their outstanding performance. In this letter, we revealed that the SL structure facilitates ferroelectric excitation by introducing local stress compared to solid solution (SS) HZO. This additional stress results in an earlier saturation of polarization during annealing process and thus less annealing time is needed for SL. The thermal defects (e.g. oxygen vacancy) are effectively mitigated, leading to a remarkable improvement in endurance simultaneously. The precise modulation of local stress achieved through stack engineering unlocks vast potential for ferroelectric devices, enabling them to exhibit superior ferroelectricity and unprecedented reliability.