Epitaxial Ferroelectric HfO2 Films: Growth, Properties, and Devices

TL;DR

This review discusses recent advances in the growth, properties, and device applications of epitaxial ferroelectric HfO2 films, highlighting their potential advantages over polycrystalline films for memory devices.

Contribution

It provides a comprehensive summary of progress in epitaxial HfO2 films since 2015, emphasizing structural, ferroelectric properties, and device fabrication techniques.

Findings

Epitaxial HfO2 films have fewer defects and better microstructure control.

Identification of the ferroelectric phase in epitaxial HfO2 has advanced.

Device fabrication using epitaxial HfO2 shows promising performance.

Abstract

About ten years after ferroelectricity was first reported in doped HfO2 polycrystalline films, there is tremendous interest in this material and ferroelectric oxides are once again in the spotlight of the memories industry. Great efforts are being made to understand and control ferroelectric properties. Epitaxial films, which have fewer defects and a more controlled microstructure than polycrystalline films, can be very useful for this purpose. Epitaxial films of ferroelectric HfO2 have been much less investigated, but after the first report in 2015 significant progress has been achieved. This review summarizes and discusses the main advances on epitaxial HfO2, considering growth, study of structural and ferroelectric properties, identification of the ferroelectric phase, and fabrication of devices. We hope this review will help researchers investigating epitaxial HfO2. It can also help extend the interest of the ferroelectric HfO2 community, now basically focused on polycrystalline samples, to epitaxial films.