Epitaxial Integration on Si(001) of Ferroelectric Hf0.5Zr0.5O2 Capacitors with High Retention and Endurance

TL;DR

This paper demonstrates the successful integration of epitaxial ferroelectric Hf0.5Zr0.5O2 films on Si(001), achieving high polarization, long retention, and endurance, advancing ferroelectric device fabrication on silicon substrates.

Contribution

It reports the first epitaxial growth of Hf0.5Zr0.5O2 on Si(001) with stable orthorhombic phase and excellent ferroelectric properties, highlighting the importance of electrode choice.

Findings

High remnant polarization (~20 μC/cm²) achieved.

Retention time exceeds 10 years at 5 MV/cm.

Endurance up to 10^9 cycles at 4 MV/cm.

Abstract

Epitaxial ferroelectric Hf0.5Zr0.5O2 films have been successfully integrated in a capacitor heterostructure on Si(001). The orthorhombic Hf0.5Zr0.5O2 phase, [111] out-of-plane oriented, is stabilized in the films. The films present high remnant polarization Pr close to 20 {\mu}C/cm2, rivaling with equivalent epitaxial films on single crystalline oxide substrates. Retention time is longer than 10 years for writing field of around 5 MV/cm, and the capacitors show endurance up to 1E9 cycles for writing voltage of around 4 MV/cm. It is found that the formation of the orthorhombic ferroelectric phase depends critically on the bottom electrode, being achieved on La0.67Sr0.33MnO3 but not on LaNiO3. The demonstration of excellent ferroelectric properties in epitaxial films of Hf0.5Zr0.5O2 on Si(001) is relevant towards fabrication of devices that require homogeneity in the nanometer scale, as well as for better understanding of the intrinsic properties of this promising ferroelectric oxide.