Oxygen Vacancy Modulation With TiO₂ Stack Interface Engineering for Ferroelectric Hf<sub>0.5</sub>Zr<sub>0.5</sub>O₂ Thin Films
Xuepei Wang, Maokun Wu, Boyao Cui, Yuchun Li, Yishan Wu, Yichen Wen, Jinhao Liu, Xiaoxi Li, S. Ye, Pengpeng Ren, Zhigang Ji, Hong-Liang Lü, David Wei Zhang, Runsheng Wang, Ru Huang
Abstract
Since the discovery of ferroelectric switching in hafnium-based thin films, this family of materials has garnered significant attention. However, their higher coercive field not only constrains endurance performance but also escalates power consumption during polarization switching, rendering them incompatible with logic circuits. In this work, we have successfully reduced the coercive field of HZO ferroelectric thin films to 0.8 MV/cm by introducing TiO2 interface layers. When compared to HZO samples, the coercive field demonstrates a 30% reduction under the same electric field. Density functional theory (DFT) results support the phenomenon of interface oxygen injection by TiO2 interface layers. Further XPS and EDS physical characterizations reveal that TiO2 interfacial layers effectively diminishes the concentration of oxygen vacancies, thereby augmenting thin film ferroelectricity and device reliability.