Structure Analysis of Hf0.5Zr0.5O2 Thin Films Crystallized from Amorphous Phase by Thermal Annealing below 500°C

Hf 0.5 Zr 0.5 O 2 (HZO) films are anticipated as a novel insulating material for ferroelectric field-effect transistors. These materials are fabricated by crystallization of amorphous HZO, and therefore knowledge of crystallization processes is required. We examined thermally-induced crystallization processes of amorphous HZO prepared by sputtering using x-ray diffraction and transmission electron microscopy. It was found that a metastable orthorhombic phase is formed in 10 nm thick HZO films after thermal annealing at 500°C.