Fabrication of ferroelectric Fe doped HfO2 epitaxial thin films by ion-beam sputtering method and their characterization
Fabrication of ferroelectric Fe doped HfO2 epitaxial thin films by ion-beam sputtering method and their characterization
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DOI：
10.7567/jjap.57.11uf02
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发表时间：
2018-08
影响因子：
1.5
通讯作者：
T. Shiraishi;Sujin Choi;T. Kiguchi;Takao Shimizu;H. Uchida;H. Funakubo;T. Konno
中科院分区：
文献类型：
--
作者：
T. Shiraishi;Sujin Choi;T. Kiguchi;Takao Shimizu;H. Uchida;H. Funakubo;T. Konno
本研究系统研究了Fe掺杂对20nm厚HfO2外延薄膜晶体结构和电学性能的影响。x射线衍射测量表明，未掺杂的HfO2薄膜由对电单斜相组成。另一方面，在Fe掺杂HfO2薄膜中观察到非中心对称正交相的形成，并且在最佳掺杂浓度下最容易促进。此外，高温x射线衍射测量表明，在500 ~ 600℃之间发生了正交相到高度对称相的转变。通过扫描透射电子显微镜对其进行微观结构分析，发现其多畴结构由正交相和单斜相组成。铁电性与Fe掺杂浓度有关，最大剩余极化值为8.8µC/cm2。这些结果表明，Fe掺杂HfO2薄膜可以作为纳米级铁电体。
In this study, the effect of Fe doping on the crystal structure and electrical properties in 20-nm-thick HfO2 epitaxial thin films were systematically investigated. X-ray diffraction measurements revealed that undoped HfO2 films were composed of a paraelectric monoclinic phase. On the other hand, the formation of non-centrosymmetric orthorhombic phase was observed in Fe doped HfO2 films and was most promoted at an optimum doping concentration. In addition, high-temperature X-ray diffraction measurements showed that an orthorhombic phase to a highly symmetric phase transition occurs between 500 and 600 °C. Microstructural analysis using scanning transmission electron microscopy revealed multidomain structure consisting of orthorhombic and monoclinic phases. Ferroelectricity depended on Fe doping concentration, and the maximum remanent polarization value was 8.8 µC/cm2. These results indicate that Fe doped HfO2 thin films can be applied as nanoscale ferroelectrics.