Phase Transitions and Anti-Ferroelectric Behaviors in Hf_1-xZr_xO₂ Films

Abstract

In this letter, we systematically studied the relationship between ferroelectricity/anti-ferroelectricity and the corresponding phase structures in Hf1-xZrxO2 (HZO) films. Our findings, obtained through ab initio simulations, indicate that the orthorhombic-I phase exhibits greater stability compared to the orthorhombic-III and tetragonal phases in the HZO system. Atomic-resolution C s-corrected scanning transmission electron microscopy revealed a direct correlation between anti-ferroelectricity and orthorhombic-I phase in HZO materials. Furthermore, the reversible transition between the tetragonal and orthorhombic-I phases has been identified as a contributing factor to the anti-ferroelectric properties observed in thin HZO films. The development of phase-engineered AFE HZO, as demonstrated in this work, holds significant promise for advanced embedded DRAM and non-volatile memory applications.