Fatigue and retention in the growth window of ferroelectric Hf0.5Zr0.5O2 thin films

TL;DR

This study defines the optimal growth conditions for ferroelectric Hf0.5Zr0.5O2 thin films, balancing polarization, fatigue, and retention, and analyzes how deposition parameters influence defect formation and device longevity.

Contribution

It establishes a comprehensive growth window for epitaxial Hf0.5Zr0.5O2 films considering multiple ferroelectric properties simultaneously.

Findings

Fatigue increases with substrate temperature and oxygen pressure.

Retention is compromised at low deposition temperatures.

The growth window narrows when optimizing for all ferroelectric properties.

Abstract

The growth window of epitaxial Hf0.5Zr0.5O2 is established taking into account the main ferroelectric properties that films have to present simultaneously: high remanent polarization, low fatigue and long retention. Defects in the film and imprint field depend on deposition temperature and oxygen pressure, with an impact on fatigue and retention, respectively. Fatigue increases with substrate temperature and pressure, and retention is short if low temperature is used. The growth window of epitaxial stabilization of ferroelectric Hf0.5Zr0.5O2 is narrower when all major ferroelectric properties (remanence, endurance and retention) are considered, but deposition temperature and pressure ranges are still sufficiently wide.