Structure-modulated phase stability and defect engineering in ferroelectric HfxZr1-xO2 heterostructures

Abstract

We demonstrate the critical impact of layer configuration in HfxZr1-xO2 (HZO) heterostructures in modulating phase stability, defect distribution, and ferroelectric reliability. Compared to the ferroelectric-seeded structure (Hetero1), adopting an antiferroelectric-seeded structure (Hetero2) reduces oxygen vacancy concentration by more than half (from 5.6 % to 2.6 %) and the non-ferroelectric monoclinic phase fraction by over 90 % (from 6.5 % to 0.5 %), while adjusting grain size. This reduction minimizes dipole pinning and defect migration, which are the main causes of wake-up dynamics. As a result, the Hetero2 maintains stable switching with an energy efficiency over six times higher than its Hetero1 counterpart after prolonged cycling. These findings demonstrate that stacking sequence is a practical knob for defect control and phase stabilization in robust HZO-based memory and logic devices.