Optimal parameter space for stabilizing the ferroelectric phase of Hf_(0.5)Zr_(0.5)O_(2) thin films under strain and electric fields  

作　　者：王侣锦 王聪 周霖蔚 周谐宇 潘宇浩 吴幸 季威 Lvjin Wang;Cong Wang;Linwei Zhou;Xieyu Zhou;Yuhao Pan;Xing Wu;Wei Ji(Beijing Key Laboratory of Optoelectronic Functional Materials&Micro-Nano Devices,Department of Physics,Renmin University of China,Beijing 100872,China;Key Laboratory of Quantum State Construction and Manipulation(Ministry of Education),Renmin University of China,Beijing 100872,China;In Situ Devices Center,School of Integrated Circuits,East China Normal University,Shanghai 200241,China)

机构地区：[1]Beijing Key Laboratory of Optoelectronic Functional Materials&Micro-Nano Devices,Department of Physics,Renmin University of China,Beijing 100872,China [2]Key Laboratory of Quantum State Construction and Manipulation(Ministry of Education),Renmin University of China,Beijing 100872,China [3]In Situ Devices Center,School of Integrated Circuits,East China Normal University,Shanghai 200241,China

出　　处：《Chinese Physics B》2024年第7期509-517,共9页中国物理B（英文版）

基　　金：Project supported by the Fund from the Ministry of Science and Technology(MOST)of China(Grant No.2018YFE0202700);the National Natural Science Foundation of China(Grant Nos.11974422 and 12104504);the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB30000000);the Fundamental Research Funds for the Central Universities;the Research Funds of Renmin University of China(Grant No.22XNKJ30)。

摘　　要：Hafnia-based ferroelectric materials, like Hf_(0.5)Zr_(0.5)O_(2)(HZO), have received tremendous attention owing to their potentials for building ultra-thin ferroelectric devices. The orthorhombic(O)-phase of HZO is ferroelectric but metastable in its bulk form under ambient conditions, which poses a considerable challenge to maintaining the operation performance of HZO-based ferroelectric devices. Here, we theoretically addressed this issue that provides parameter spaces for stabilizing the O-phase of HZO thin-films under various conditions. Three mechanisms were found to be capable of lowering the relative energy of the O-phase, namely, more significant surface-bulk portion of(111) surfaces, compressive c-axis strain,and positive electric fields. Considering these mechanisms, we plotted two ternary phase diagrams for HZO thin-films where the strain was applied along the in-plane uniaxial and biaxial, respectively. These diagrams indicate the O-phase could be stabilized by solely shrinking the film-thickness below 12.26 nm, ascribed to its lower surface energies. All these results shed considerable light on designing more robust and higher-performance ferroelectric devices.

关 键 词：Hf_(0.5)Zr_(0.5)O_(2) orthorhombic phase ferroelectric films phase stability thickness-dependent ternary phase diagrams 

分 类 号：O469[理学—凝聚态物理]