Interplay between oxygen defects and dopants: effect on structure and performance of HfO2-based ferroelectrics

Abstract

Ten years after the first report on ferroelectricity in HfO₂, researchers are still occupied unraveling the different causes behind this phenomenon. Among them, oxygen related defects seem to play a major role, affecting both crystalline phase formation and performance of HfO₂-based devices. This review surveys the available literature and provides a broad picture on the topic, starting with an overview of existing oxygen-related defects, assessing the extensive calculations and experimental reports on phase stabilization in both undoped and doped HfO₂ and concluding with a discussion of device reliability involving oxygen vacancies, first in more classical HfO₂ applications such as MOSFET high-k metal gate and resistive switching devices and later in the three major groups of ferroelectric non-volatile memory devices.