Memory Window Expansion in HfO2-Based FeFETs Through Trap-to-Dipole Conversion

Abstract

We investigated a memory window (MW) expansion mechanism in HfxZr1-xO2 (HZO)-based ferroelectric field-effect transistors (FeFETs) enabled by field-induced trap neutralization. Under strong programming conditions, injected electrons neutralize charged defect sites that initially pin dipoles, leading to depinning and additional polarization switching beyond the intrinsic ferroelectric saturation limit. This results in a progressive, temperature- and voltage-dependent MW expansion. A clear switching crossover is observed-from intrinsic ferroelectric to trap-mediated behavior-as programming amplitude increases. The proposed mechanism provides a pathway to access wider and stable MWs by depinning trapped dipoles, offering insights for further FeFET design.