Optimizing Al-doped ZrO2 as the gate dielectric for MoS2 field-effect transistors

Xingjuan Song, Jingping Xu, Lu Liu, Yuheng Deng, Pui To Lai, Wing Man Tang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

3 Citations (Scopus)

Abstract

In this work, we investigate the effects on the electrical properties of few-layered MoS2 field-effect transistors (FETs) following Al incorporation into ZrO2 as the gate dielectrics of the devices. A large improvement in device performance is achieved with the Al-doped ZrO2 gate dielectric when Zr:Al = 1:1. The relevant MoS2 transistor exhibits the best electrical characteristics: high carrier mobility of 40.6 cm2 V-1 s-1 (41% higher than that of the control sample, and an intrinsic mobility of 68.0 cm2 V-1 s-1), a small subthreshold swing of 143 mV dec-1, high on/off current ratio of 6 × 106 and small threshold voltage of 0.71 V. These are attributed to the facts that (i) Al incorporation into ZrO2 can decrease its oxygen vacancies; densify the dielectric film; and smooth the gate dielectric surface, thus reducing the traps at/near the Zr0.5Al0.5Oy/MoS2 interface and the gate leakage current; (ii) adjusting the dielectric constant of the gate dielectric to an appropriate value, which achieves a reasonable trade-off between the gate screening effect on the Coulomb-impurity scattering and the surface optical phonon scattering. These results demonstrate that optimized Zr0.5Al0.5Oy is a potential gate dielectric material for MoS2 FET applications.

Original languageEnglish
Article number135206
JournalNanotechnology
Volume31
Issue number13
DOIs
Publication statusPublished - 14 Jan 2020

Keywords

  • capacitance-equivalent thickness
  • carrier mobility
  • interface-state density
  • MoS FETs
  • oxide capacitance
  • subthreshold swing
  • ZrAO dielectric

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering

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