Impact of Pre-Annealed ZrO2 Interfacial Layer on the Ferroelectric Behavior of Hf0.5Zr0.5O2

• Published in: Electronics (Basel) Vol. 13; no. 1; p. 3
• Main Authors: Yuan, Xiaobo, Liu, Zongfang, Qi, Jiabin, Xiao, Jinpan, He, Huikai, Tang, Wentao, Lee, Choonghyun, Zhao, Yi
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.01.2024
• Subjects: Annealing; Capacitors; Electric fields; Electrodes; Ferroelectric materials; Ferroelectricity; Orthorhombic phase; Silicon dioxide; Thin films; Titanium nitride; Zirconium dioxide
• ISSN: 2079-9292; 2079-9292
• DOI: 10.3390/electronics13010003

This work systematically investigates the impact of a pre-annealed ZrO2 interfacial layer on the ferroelectric behavior of Hf0.5Zr0.5O2 (HZO) capacitors. The remanent polarization (2Pr) value of HZO capacitors, including configurations such as W/HZO/TiN/p+ Si, W/HZO/(pre-annealed) ZrO2/TiN/p+ Si, W/HZO/SiO2/TiN/p+ Si, and W/HZO/SiO2/p+ Si, exhibits significant variations. The W/HZO/(pre-annealed) ZrO2/TiN/p+ Si capacitor demonstrates superior ferroelectric performance, with a 2Pr value of ~32 µC/cm2. Furthermore, by optimizing the thickness combination of HZO and the pre-annealed ZrO2 interfacial layer, a capacitor with a 10 nm HZO and 2 nm ZrO2 achieves the largest 2Pr value. The pre-annealing process applied to ZrO2 is found to play a very important role in inducing the orthorhombic phase and thus enhancing ferroelectricity. This enhancement is attributed to the pre-annealed 2 nm ZrO2 interfacial layer acting as a structural guide for the subsequent HZO orthorhombic phase, thereby improving the ferroelectric performance of HZO capacitors. These findings provide a comprehensive explanation and experimental verification of the impact of pre-annealed ZrO2 on ferroelectric devices, offering novel insights for the optimization of ferroelectric properties.