Vibrational fingerprints of ferroelectric HfO2
Vibrational fingerprints of ferroelectric HfO2
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DOI：
10.1038/s41535-022-00436-8
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发表时间：
2022-03-18
影响因子：
5.7
通讯作者：
Musfeldt, J. L.
中科院分区：
文献类型：
--
作者：
Fan, Shiyu;Singh, Sobhit;Musfeldt, J. L.
Hafnia（HfO2）由于其高kappa介电行为、对负电容异质结构的适用性、可扩展的铁电性和硅兼容性而成为新兴芯片应用的有前途的材料。晶格动力学沿着与声子性质，如热导率，收缩，和热容量的探索不足，主要是由于缺乏高品质的单晶。在这里，我们报告了一系列的HfO2晶体稳定与钇（化学式HfO2：xY，其中x = 20，12，11，8和0%）的振动特性，并比较我们的研究结果与对称性分析和晶格动力学计算。我们解开Y的影响，通过测试我们的计算对测得的拉曼和红外光谱的立方，反极性正交，和单斜相，然后继续揭示极性正交晶系的特征模式。这项工作提供了一个光谱指纹的HfO2的几个不同的阶段，并铺平了道路，为分析模式的贡献，高kappa介电和铁电性能的芯片技术。
Hafnia (HfO2) is a promising material for emerging chip applications due to its high-kappa dielectric behavior, suitability for negative capacitance heterostructures, scalable ferroelectricity, and silicon compatibility. The lattice dynamics along with phononic properties such as thermal conductivity, contraction, and heat capacity are under-explored, primarily due to the absence of high quality single crystals. Herein, we report the vibrational properties of a series of HfO2 crystals stabilized with yttrium (chemical formula HfO2: xY, where x = 20, 12, 11, 8, and 0%) and compare our findings with a symmetry analysis and lattice dynamics calculations. We untangle the effects of Y by testing our calculations against the measured Raman and infrared spectra of the cubic, antipolar orthorhombic, and monoclinic phases and then proceed to reveal the signature modes of polar orthorhombic hafnia. This work provides a spectroscopic fingerprint for several different phases of HfO2 and paves the way for an analysis of mode contributions to high-kappa dielectric and ferroelectric properties for chip technologies.