Atomic-scale characterization of defects generation during fatigue in ferroelectric Hf0.5Zr0.5O2 films: vacancy generation and lattice dislocation

For the first time, we directly observed the lattice dislocation and monoclinic (m-) phase formation in ferroelectric Hf 0.5 Zr 0.5 O 2 (HZO) films during fatigue, through the spherical aberration (Cs)-corrected transmission electron microscopy (TEM) technique. The main observations are: 1. More oxy...

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Bibliographic Details
Main Authors: Zheng, Yunzhe, Zheng, Yonghui, Gao, Zhaomeng, Yuan, Jun-Hui, Cheng, Yan, Zhong, Qilan, Xin, Tianjiao, Wang, Yiwei, Liu, Cheng, Huang, Yaru, Huang, Rong, Miao, Xiangshui, Xue, Kan-Hao, Lyu, Hangbing
Format: Conference Proceeding
Language:English
Subjects:
Fatigue
Ferroelectric materials
Grain size
Lattices
Microscopy
Transmission electron microscopy
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Summary:For the first time, we directly observed the lattice dislocation and monoclinic (m-) phase formation in ferroelectric Hf 0.5 Zr 0.5 O 2 (HZO) films during fatigue, through the spherical aberration (Cs)-corrected transmission electron microscopy (TEM) technique. The main observations are: 1. More oxygen vacancies (Vo) tend to be generated when the orthorhombic (o-) phase polar axis is close to the out-of-plane direction (parallel to the electrical field); 2. The o-phase with large grain size tends to fragment with lattice dislocation and m-phase formation by martensitic-like transformation; 3. At the interface of m-/o-structure, the Vo formation energies are lowered. This work provides fundamental understanding on the defect generation mechanism of HZO film at the atomic-level, laying a solid foundation to further optimization and commercialization of the ferroelectric HZO devices.
ISSN:2156-017X
DOI:10.1109/IEDM19574.2021.9720565