Origins and characteristics of the threshold voltage variability of quasiballistic single-walled carbon nanotube field-effect transistors

Qing Cao, Shu Jen Han, Ashish V. Penumatcha, Martin M. Frank, George S. Tulevski, Jerry Tersoff, Wilfried E. Haensch

Research output: Contribution to journalArticle

Abstract

Ultrascaled transistors based on single-walled carbon nanotubes are identified as one of the top candidates for future microprocessor chips as they provide significantly better device performance and scaling properties than conventional silicon technologies. From the perspective of the chip performance, the device variability is as important as the device performance for practical applications. This paper presents a systematic investigation on the origins and characteristics of the threshold voltage (VT) variability of scaled quasiballistic nanotube transistors. Analysis of experimental results from variable-temperature measurement as well as gate oxide thickness scaling studies shows that the random variation from fixed charges present on the oxide surface close to nanotubes dominates the VTvariability of nanotube transistors. The VTvariability of single-tube transistors has a figure of merit that is quantitatively comparable with that of current silicon devices; and it could be reduced with the adoption of improved device passivation schemes, which might be necessary for practical devices incorporating multiple nanotubes, whose area normalized VTvariability becomes worse due to the synergic effects from the limited surface coverage of nanotubes and the nonlinearity of the device off-state leakage current, as predicted by the Monte Carlo simulation.

Original languageEnglish (US)
Pages (from-to)1936-1944
Number of pages9
JournalACS Nano
Volume9
Issue number2
DOIs
StatePublished - Feb 24 2015
Externally publishedYes

Keywords

  • carbon nanotube
  • threshold voltage
  • transistor
  • variability

ASJC Scopus subject areas

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

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