论文标题
在铁电器设备中对可逆的氧迁移和相变的观察
Operando observation of reversible oxygen migration and phase transitions in ferroelectric devices
论文作者
论文摘要
基于Hafnia的薄膜表现出非常规的纳米级尺寸的非常规的铁电性，在纳米电子学上提供了巨大的机会。但是，极化切换的确切性质仍然存在争议。在这里，我们研究了外部hf0.5zr0.5O2（HzO）电容器，该电容器与氧电导金属（LA0.67SR0.33MNO3，LSMO）连接为电极作为电极，使用原子分辨率电子显微镜，同时现有电气偏置。通过直接氧成像，我们观察到通过HZO从底部到顶部电极的可逆氧空位迁移，并揭示了外部LSMO和HZO层中相关的可逆结构相变。我们遵循原子量表的相变路径，并确定这些机制在隧道连接中都在发挥作用，而用亚毫秒脉冲切换的铁电容器也可以。我们的结果无疑表明，氧气伏安法和极化切换在这些材料中交织在一起。
Unconventional ferroelectricity, robust at reduced nanoscale sizes, exhibited by hafnia-based thin-films presents tremendous opportunities in nanoelectronics. However, the exact nature of polarization switching remains controversial. Here, we investigate epitaxial Hf0.5Zr0.5O2 (HZO) capacitors, interfaced with oxygen conducting metals (La0.67Sr0.33MnO3, LSMO) as electrodes, using atomic resolution electron microscopy while in situ electrical biasing. By direct oxygen imaging, we observe reversible oxygen vacancy migration from the bottom to the top electrode through HZO and reveal associated reversible structural phase transitions in the epitaxial LSMO and HZO layers. We follow the phase transition pathways at the atomic scale and identify that these mechanisms are at play both in tunnel junctions and ferroelectric capacitors switched with sub-millisecond pulses. Our results unmistakably demonstrate that oxygen voltammetry and polarization switching are intertwined in these materials.
