荷兰格罗宁根大学Beatriz Noheda团队揭示了铪基铁电器件中的可逆氧迁移和相变。相关研究成果发表在2021年4月15日出版的《科学》。

铪基薄膜在纳米尺度上表现出的非传统铁电性为纳米电子学提供了巨大的机遇。然而，偏振切换的确切性质仍然存在争议。

研究人员使用能够直接氧成像的原子分辨显微镜以及同步辐射纳米束衍射研究原位电偏压下与不同顶电极连接的La0.67Sr0.33MnO3/Hf0.5Zr0.5O2电容器。当顶电极为氧反应性时，研究人员清楚地观察到可逆的氧空位迁移，电极是氧源和氧阱，而介电层在毫秒时间尺度上起着快速通道的作用。

对于无反应的顶部电极以及较长的时间尺度（秒）下，介电层充当氧源/氧阱。结果表明，铪基薄膜的铁电性与氧的伏安特性有着紧密的联系。

附：英文原文

Title: Reversible oxygen migration and phase transitions in hafnia-based ferroelectric devices

Author: Pavan Nukala, Majid Ahmadi, Yingfen Wei, Sytze de Graaf, Evgenios Stylianidis, Tuhin Chakrabortty, Sylvia Matzen, Henny W. Zandbergen, Alexander Bjrling, Dan Mannix, Dina Carbone, Bart Kooi, Beatriz Noheda

Issue&Volume: 2021/04/15

Abstract: Unconventional ferroelectricity exhibited by hafnia-based thin films, robust at nanoscale sizes, presents tremendous opportunities in nanoelectronics. However, the exact nature of polarization switching remains controversial. We investigated La0.67Sr0.33MnO3/Hf0.5Zr0.5O2 capacitor interfaced with various top electrodes while in situ electrical biasing using atomic resolution microscopy with direct oxygen imaging, as well as synchrotron nanobeam diffraction. When the top electrode is oxygen reactive, we clearly show reversible oxygen vacancy migration with electrodes being the source and sink of oxygen, and the dielectric layer acting as a fast conduit at millisecond timescales. With non-reactive top electrodes and at longer time scales (seconds), the dielectric layer also acts as an oxygen source/sink. Our results show that ferroelectricity in hafnia-based thin films is unmistakably intertwined to oxygen voltammetry.

DOI: 10.1126/science.abf3789

Source: https://science.sciencemag.org/content/early/2021/04/14/science.abf3789