Rapid Research Letters

Ferroelectric hafnium oxide (HfO2) is considered a very prospective material for applications in integrated devices due to its considerably large spontaneous polarization and superior thickness scaling. In fact, the evolution of the ferroelectric hysteresis upon field cycling plays an important role in most applications; especially the so‐called wake‐up effect that describes the increase of remanent polarization for initial field cycling, needs a profound understanding in HfO2. Herein, the discovery of electric field–induced crystallization in hafnium oxide is reported. In addition, differences in the wake‐up behavior are addressed that finally can be categorized into five different cases, all being relevant when describing the evolution of ferroelectricity. Moreover, analysis of the temperature dependence and transmission Kikuchi diffraction provides insight into the underlying physical mechanisms of different wake‐up behavior scenarios, and proves ferroelastic switching as the origin for the observed antiferroelectric‐like behavior. This knowledge provides clear procedures of 1) how to experimentally quantify and 2) how to prepare and manufacture hafnium oxide phases for the five different wake‐up types.