Regulating crystal structure and ferroelectricity in Sr doped HfO2 thin films fabricated by metallo-organic decomposition
Regulating crystal structure and ferroelectricity in Sr doped HfO2 thin films fabricated by metallo-organic decomposition
复制标题
金属有机分解制备的 Sr 掺杂 HfO2 薄膜的晶体结构和铁电性调控
DOI：
10.1016/j.ceramint.2018.10.214
复制
发表时间：
2019
影响因子：
5.2
通讯作者：
Zhou Kechao
中科院分区：
文献类型：
--
作者：
Tang Lin;Chen Chao;Wei Anqi;Li Kun;Zhang Dou;Zhou Kechao
HfO 2基二元铁电氧化物由于其与现有Si基工艺的兼容性，有望成为非易失性存储器件的候选材料。采用金属有机物分解法（MOD）在铂电极上制备了Sr掺杂HfO 2（Sr：HfO 2）铁电薄膜，Sr掺杂浓度为0%~ 10mol%。结果表明，在700 °C退火条件下，用MOD法可以制备出表面粗糙度极低的均匀Sr：HfO 2薄膜。由于在105次循环测试后获得了13.3 µC/cm 2的剩余极化和30的高介电常数，因此认为唤醒阶段对MOD衍生的Sr：HfO 2薄膜的铁电性更为重要。随着Sr浓度的增加和薄膜厚度的增加，薄膜的相结构发生了从单斜相到立方相的转变。X射线光电子能谱分析证实了薄膜中O-Hf-O和O-Sr-O键的成键类型。用高分辨透射电子显微镜观察了铁电正交相的微观晶体结构。在电流-电压曲线上，出现了明显的电流峰和极化滞后回线，证明了Sr：HfO 2薄膜具有本征铁电性。稳定的域结构和其开关动力学监测piezoresponse力显微镜，表明本机极化的Sr：HfO 2。本工作为MOD法制备HfO 2基铁电薄膜提供了一种可控的方法。
HfO2based binary ferroelectric oxides are promising candidate for nonvolatile memory devices due to their compatibility with the current Si-based technology. In this work, Sr doped HfO2(Sr:HfO2) ferroelectric thin films with Sr concentration from 0% to 10 mol% were prepared on the platinum electrodes by metallo-organic decomposition (MOD). It was demonstrated that uniform Sr:HfO2thin films with extremely low roughness can be achieved and crystallized by MOD under a 700 °C annealing process. A wake-up stage was believed more essential for the ferroelectricity of the MOD derived Sr:HfO2thin film, since the remnant polarization of 13.3 µC/cm2and high dielectric constant of 30 were obtained after 105cycling tests. The transformation from monoclinic phase to cubic phase was observed with increasing the Sr concentration and the thickness of the films. X-ray photoelectron spectroscopy analysis confirmed the bonding type of O-Hf-O and O-Sr-O bonds in the film. The microscopic crystal structure of ferroelectric orthorhombic phase was observed by high resolution transmission electronic microscope. The intrinsic ferroelectricity of Sr:HfO2film was demonstrated by the hysteresis polarization-voltage loops and distinct current peaks in the current-voltage curve. Stable domain structure and its switching dynamics were monitored by piezoresponse force microscopy, indicating the native polarization of Sr:HfO2. This work will provide a controllable routine to fabricate ferroelectric HfO2based thin films using MOD method.