Atomic-scale characterization of defects generation during fatigue in ferroelectric Hf 0.5 Zr 0.5 O 2 films: vacancy generation and lattice dislocation

作者：Yunzhe Zheng, Yonghui Zheng, Zhaomeng Gao, Jun‐Hui Yuan, Yan Cheng, Qilan Zhong, Tianjiao Xin, Yiwei Wang, Cheng Liu, Yaru Huang, Rong Huang, Xiangshui Miao, Kan‐Hao Xue, Hangbing Lyu · 年份：2021 · DOI：10.1109/iedm19574.2021.9720565 · 被引用次数：30 · 研究领域：Ferroelectric and Negative Capacitance Devices、MXene and MAX Phase Materials、Semiconductor materials and devices

For the first time, we directly observed the lattice dislocation and monoclinic (m-) phase formation in ferroelectric Hf0.5Zr0.5O2(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.