Improved interfacial and electrical properties of few-layered MoS 2 FETs with plasma-treated Al 2 O 3 as gate dielectric

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

Research output: Journal article publicationJournal articleAcademic researchpeer-review

9 Citations (Scopus)

Abstract

ALD Al 2 O 3 films treated respectively by N 2 , O 2 and NH 3 plasmas are used as gate dielectrics to fabricate few-layered MoS 2 FETs. As compared with the control sample without any plasma treatment, the devices with different plasmas treatments achieve better electrical properties, with the NH 3 -treated device having the best results: highest carrier mobility of 39.3 cm 2 /Vs (~1.65 times higher than that of the control sample), smallest subthreshold swing of 90.9 mV/dec, largest on/off ratio of 1.5 × 10 7 and negligible hysteresis. These are attributed to the fact that the NH 3 plasma treatment can (1) effectively passivate the oxygen vacancies in Al 2 O 3 and decrease the dangling bonds at the Al 2 O 3 surface, thus reducing the traps at/near the Al 2 O 3 /MoS 2 interface; (2) increase the k value of the dielectric by N incorporation to enhance the screening effect on the Coulomb impurity scattering. In addition, these plasma treatments can adjust the MoS 2 FET from depletion mode to enhancement mode by introducing negative ions into the gate dielectric.

Original languageEnglish
Pages (from-to)1028-1034
Number of pages7
JournalApplied Surface Science
Volume481
DOIs
Publication statusPublished - 1 Jul 2019

Keywords

  • Al O dielectric
  • Mobility
  • MoS FETs
  • Plasma treatment

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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