Mesostructured HfxAlyO2 Thin Films as Reliable and Robust Gate Dielectrics with Tunable Dielectric Constants for High-Performance Graphene-Based Transistors

Yunseong Lee, Woojin Jeon, Yeonchoo Cho, Min Hyun Lee, Seong Jun Jeong, Jongsun Park, Seongjun Park

    Research output: Contribution to journalArticlepeer-review

    24 Citations (Scopus)

    Abstract

    We introduce a reliable and robust gate dielectric material with tunable dielectric constants based on a mesostructured HfxAlyO2 film. The ultrathin mesostructured HfxAlyO2 film is deposited on graphene via a physisorbed-precursor-assisted atomic layer deposition process and consists of an intermediate state with small crystallized parts in an amorphous matrix. Crystal phase engineering using Al dopant is employed to achieve HfO2 phase transitions, which produce the crystallized part of the mesostructured HfxAlyO2 film. The effects of various Al doping concentrations are examined, and an enhanced dielectric constant of ∼25 is obtained. Further, the leakage current is suppressed (∼10-8 A/cm2) and the dielectric breakdown properties are enhanced (breakdown field: ∼7 MV/cm) by the partially remaining amorphous matrix. We believe that this contribution is theoretically and practically relevant because excellent gate dielectric performance is obtained. In addition, an array of top-gated metal-insulator-graphene field-effect transistors is fabricated on a 6 in. wafer, yielding a capacitance equivalent oxide thickness of less than 1 nm (0.78 nm). This low capacitance equivalent oxide thickness has important implications for the incorporation of graphene into high-performance silicon-based nanoelectronics.

    Original languageEnglish
    Pages (from-to)6659-6666
    Number of pages8
    JournalACS Nano
    Volume10
    Issue number7
    DOIs
    Publication statusPublished - 2016 Jul 26

    Keywords

    • atomic layer deposition
    • capacitance equivalent oxide thickness
    • graphene
    • mesostructure
    • phase transition engineering

    ASJC Scopus subject areas

    • General Engineering
    • General Materials Science
    • General Physics and Astronomy

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