Performance enhancement of monolayer MoS2 transistors by atomic layer deposition of high-k dielectric assisted by Al2O3 seed layer

Guangyang Lin, Meng Qiang Zhao, Meng Jia, Jie Zhang, Peng Cui, Lincheng Wei, Haochen Zhao, A. T.Charlie Johnson, Lars Gundlach, Yuping Zeng

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

In this work, thermal atomic layer deposition (ALD) of HfO2 on monolayer (ML) MoS2 with 1 nm Al2O3 seed layer by e-beam evaporation was explored. With the 1 nm Al2O3 seed layer, a uniform HfO2 layer can be deposited on the ML MoS2 with bare influence on the ML MoS2 structure. After coating a uniform HfO2, abundant electrons are accumulated in MoS2 and SiO2 resulting in a high on/off current ratio of ∼109 and a dramatic reduction of subthreshold swing (SS) from 1943 to 168 mV/dec of back-gated ML MoS2 transistor on 300 nm SiO2. A low SS of 103 mV/dec was further obtained from top-gated transistor with ∼23.3 nm HfO2 as the gate oxide. The results manifest the beneficial influence of using 1 nm Al2O3 on the electrical performance of ML MoS2 transistors, suggesting a feasible strategy for ALD of high-k dielectric layer on ML 2D materials.

Original languageEnglish (US)
Article number105103
JournalJournal of Physics D: Applied Physics
Volume53
Issue number10
DOIs
StatePublished - 2020
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Acoustics and Ultrasonics
  • Surfaces, Coatings and Films

Keywords

  • AlO seed layer
  • Atomic layer deposition
  • High on/off current ratio
  • High-k dielectric
  • Low subthreshold swing
  • Monolayer MoS

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