Combined effects of the deposition temperature and metal electrodes on ferroelectric properties of atomic-layer-deposited Hf0.5Zr0.5O2 films

Abstract

Abstract The combined effects of the atomic-layer-deposition (ALD) temperature (220 °C–280 °C) and metal electrodes (TiN and Mo) on the ferroelectric properties of Hf0.5Zr0.5O2 films were studied. Regardless of the metal electrode, a tetragonal–orthorhombic–monoclinic phase evolution sequence was observed with increasing ALD temperature after post-metallization annealing. However, the phase transition temperature slightly changed depending on the metal electrode, which was predetermined based on the as-deposited states. Additionally, the out-of-plane orientation of the final orthorhombic grains was highly dependent on the crystallographic alignment of the metal electrode grains, resulting in different values of the maximum remanent polarization. In terms of long-term reliability, the fatigue characteristics were highly dependent on the electrode characteristics, and the wake-up characteristics were mainly affected by the initial phase distribution determined by both the ALD temperature and metal electrode.