Dual Ferroelectric Polarization and Dielectric Response Improvement in Epitaxial Hf0.5Zr0.5O2/HfO2 Nanolaminates

Nanolaminates based on ferroelectric polycrystalline doped HfO2 have gained interest because those compounds show enhanced functional properties. Here, we achieve coexisting improvement of remanent polarization and dielectric permittivity in wake-up-free epitaxial Hf0.5Zr0.5O2/HfO2 nanolaminates with different numbers of HfO2 nanolayers if compared with Hf0.5Zr0.5O2 single films of equivalent thickness or other reported polycrystalline nanolaminates. Comprehensive structural characterization reveals that the origin of the enhancement must be the larger amount of the orthorhombic phase in the nanolaminates. The retention of nanolaminates is greater than that of Hf0.5Zr0.5O2 single films; however, fatigue is larger and ferroelectric switching is slower in the nanolaminates compared with single layers. The present work reveals nanolamination in high-quality films as a strategy to increase dielectric permittivity without important degradation of other functional properties.