Cooling conditions are critical in the crystallization of polycrystalline films of ferroelectric HfO2 because the energy of the HfO2 polymorphs is very sensitive to oxygen vacancies and because of the role of kinetics in the stabilization of the metastable orthorhombic phase. Here, we investigate the relevance of cooling conditions in the pulsed laser deposition of epitaxial Hf0.5Zr0.5O2 films. The orthorhombic phase crystallized in epitaxial Hf0.5Zr0.5O2 films does not change when highly reducing or oxidizing cooling conditions are used.
The films exhibit similar ferroelectric properties, including polarization value, absence of the wake-up effect, comparable fatigue, and high retention. These results demonstrate that the phases formed in epitaxial films are highly stable and much less sensitive to cooling conditions than polycrystalline films.
Oxides for new-generation electronics
Highly Stable Epitaxially Crystallized Ferroelectric Hf0.5Zr0.5O2 Films
Xueliang Lyu, Tingfeng Song, Alberto Quintana, Ignasi Fina*, and Florencio Sánchez*
ACS Appl. Electron. Mater. 2023, XXXX, XXX, XXX-XXX