Optimization of the In Situ Biasing FIB Sample Preparation for Hafnia-Based Ferroelectric Capacitor
Qilan Zhong,
Yiwei Wang,
Yan Cheng,
Zhaomeng Gao,
Yunzhe Zheng,
Tianjiao Xin,
Yonghui Zheng,
Rong Huang,
Hangbing Lyu
Affiliations
Qilan Zhong
Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, East China Normal University, 500 Dong-chuan Road, Shanghai 200241, China
Yiwei Wang
Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, East China Normal University, 500 Dong-chuan Road, Shanghai 200241, China
Yan Cheng
Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, East China Normal University, 500 Dong-chuan Road, Shanghai 200241, China
Zhaomeng Gao
Key Laboratory of Microelectronics Devices and Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, 3 Bei-tu-cheng West Road, Beijing 100029, China
Yunzhe Zheng
Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, East China Normal University, 500 Dong-chuan Road, Shanghai 200241, China
Tianjiao Xin
Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, East China Normal University, 500 Dong-chuan Road, Shanghai 200241, China
Yonghui Zheng
Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, East China Normal University, 500 Dong-chuan Road, Shanghai 200241, China
Rong Huang
Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, East China Normal University, 500 Dong-chuan Road, Shanghai 200241, China
Hangbing Lyu
Key Laboratory of Microelectronics Devices and Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, 3 Bei-tu-cheng West Road, Beijing 100029, China
Hafnia-based ferroelectric (FE) thin films have received extensive attention in both academia and industry, benefitting from their outstanding scalability and excellent CMOS compatibility. Hafnia-based FE capacitors in particular have the potential to be used in dynamic random-access memory (DRAM) applications. Obtaining fine structure characterization at ultra-high spatial resolution is helpful for device performance optimization. Hence, sample preparation by the focused ion beam (FIB) system is an essential step, especially for in situ biasing experiments in a transmission electron microscope (TEM). In this work, we put forward three tips to improve the success rate of in situ biasing experiments: depositing a carbon protective layer to position the interface, welding the sample on the top of the Cu column of the TEM grid, and cutting the sample into a comb-like shape. By these means, in situ biasing of the FE capacitor was realized in TEM, and electric-field-induced tetragonal (t-) to monoclinic (m-) structure transitions in Hf0.5Zr0.5O2 FE film were observed. The improvement of FIB sample preparation technology can greatly enhance the quality of in situ biasing TEM samples, improve the success rate, and extend from capacitor sample preparation to other types.
