Accelerated ferroelectric phase transformation in HfO2/ZrO2 nanolaminates

Abstract

Ferroelectric phase transformation was compared between the Hf0.5Zr0.5O2 solid solution films and the HfO2/ZrO2 nanolaminate films, prepared by sputter deposition without heat treatment and crystallized by following cap annealing. Physical analyses showed that nanolaminate structures and their interfaces were robust even after high-temperature annealing. Ferroelectricity appeared largely in the nanolaminate films than in the solid solution film, and the best performance was attained in the nanolaminate film with the cycle thickness of monolayer oxide (0.25 nm). Long period annealing cleared that the ferroelectric phase transformation is greatly accelerated in the nanolaminate films than in the solid solution films.