High polarization, endurance and retention in sub-5 nm Hf$_{0.5}$Zr$_{0.5}$O$_2$ films

TL;DR

This study demonstrates that sub-5 nm epitaxial Hf0.5Zr0.5O2 ferroelectric films achieve high polarization, endurance, and retention simultaneously, overcoming a longstanding dilemma in ferroelectric memory materials.

Contribution

The paper reports the first demonstration of ultra-thin, epitaxial Hf0.5Zr0.5O2 films with combined high polarization, endurance, and retention, suitable for advanced ferroelectric devices.

Findings

High polarization (2Pr of 27 μC/cm²) in pristine state.

Endurance with 2Pr > 6 μC/cm² after 10¹¹ cycles.

Retention extrapolated at 10 years with 2Pr > 12 μC/cm².

Abstract

Ferroelectric HfO$_2$ is a promising material for new memory devices, but significant improvement of important properties is necessary to reach applications. However, precedent literature shows that a dilemma between polarization, endurance and retention exists. Since all these properties should be simultaneously high, overcoming this issue is of the highest relevance. Here, we demonstrate that high crystalline quality sub-5 nm Hf0.5Zr0.5O2 capacitors, integrated epitaxially with Si(001), present combined high polarization (2Pr of 27 uC/cm2 in the pristine state), endurance (2Pr > 6 uC/cm2 after E11 cycles) and retention (2Pr > 12 uC/cm2 extrapolated at 10 years) using same poling conditions (2.5 V). This achievement is demonstrated in films thinner than 5 nm, thus opening bright possibilities in ferroelectric tunnel junctions and other devices.