论文标题
通过干涉压电力显微镜探索氧化掺杂hafnium氧化物中的纳米级铁电性
Exploring Nanoscale Ferroelectricity in Doped Hafnium Oxide by Interferometric Piezoresponse Force Microscopy
论文作者
论文摘要
鉴于它们与传统的硅CMOS技术的兼容性，高可切换极化，良好的耐耐力和厚度可伸缩性，氧化物（HFO2）基于HAFNIUM（HFO2）为记忆和逻辑设备提供了非凡的希望。在过去的几年中，这些因素导致对这类材料的研究急剧上升。同时，仅存在有关纳米级铁电特性直接感测的少数报道，其中还有许多有关这些材料中铁电性出现的问题。虽然在纳米级上的压电力显微镜（PFM）非常适合于探测压电和铁电性，但已知众所周知，它会遭受伪影，这使得对结果的定量解释复杂化，甚至可能导致铁电性在非铁电离的材料中的主张。在本文中，我们探讨了使用基于干涉量比传感（IDS）改进的PFM方法研究的可能性，以研究裸露的SI掺杂HFO2中的纳米级铁电性。我们的结果表明，各种HFO2微晶的局部残留状态有明显的差异，报告的压电偶联值范围为0.6-1.5 pm/v。此外，我们报告了异常的铁电极化转换，包括电术和蔬菜效应的可能贡献，这可能表明氧空位或界面效应会影响HFO2中纳米级铁电性的出现。
Hafnium oxide (HfO2)-based ferroelectrics offer remarkable promise for memory and logic devices in view of their compatibility with traditional silicon CMOS technology, high switchable polarization, good endurance and thickness scalability. These factors have led to steep rise in research on this class of materials over the past number of years. At the same time, only a few reports on the direct sensing of nanoscale ferroelectric properties exist, with many questions remaining regarding the emergence of ferroelectricity in these materials. While piezoresponse force microscopy (PFM) is ideally suited to probe piezo- and ferro-electricity on the nanoscale, it is known to suffer artifacts which complicate quantitative interpretation of results and can even lead to claims of ferroelectricity in materials which are not ferroelectric. In this paper we explore the possibility of using an improved PFM method based on interferometric displacement sensing (IDS) to study nanoscale ferroelectricity in bare Si doped HfO2. Our results indicate a clear difference in the local remnant state of various HfO2 crystallites with reported values for the piezoelectric coupling in range 0.6-1.5 pm/V. In addition, we report unusual ferroelectric polarization switching including possible contributions from electrostriction and Vegard effect, which may indicate oxygen vacancies or interfacial effects influence the emergence of nanoscale ferroelectricity in HfO2.
