Interactions of hydrogen with amorphous hafnium oxide

Moloud Kaviani, Valeri V. Afanas'Ev, Alexander L. Shluger

    研究成果: Article査読

    15 被引用数 (Scopus)

    抄録

    We used density functional theory (DFT) calculations to study the interaction of hydrogen with amorphous hafnia (a-HfO2) using a hybrid exchange-correlation functional. Injection of atomic hydrogen, its diffusion towards electrodes, and ionization can be seen as key processes underlying charge instability of high-permittivity amorphous hafnia layers in many applications. Hydrogen in many wide band gap crystalline oxides exhibits negative-U behavior (+1 and -1 charged states are thermodynamically more stable than the neutral state). Our results show that in a-HfO2 hydrogen is also negative-U, with charged states being the most thermodynamically stable at all Fermi level positions. However, metastable atomic hydrogen can share an electron with intrinsic electron trapping precursor sites [Phys. Rev. B 94, 020103 (2016).2469-995010.1103/PhysRevB.94.020103] forming a [etr-+O-H] center, which is lower in energy on average by about 0.2 eV. These electron trapping sites can affect both the dynamics and thermodynamics of the interaction of hydrogen with a-HfO2 and the electrical behavior of amorphous hafnia films in CMOS devices.

    本文言語English
    論文番号075117
    ジャーナルPhysical Review B
    95
    7
    DOI
    出版ステータスPublished - 2017 2月 8

    ASJC Scopus subject areas

    • 電子材料、光学材料、および磁性材料
    • 凝縮系物理学

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