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 journalArticle

10 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

  • Engineering(all)
  • Materials Science(all)
  • Physics and Astronomy(all)

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