Epitaxial tunnel layer structure for P-channel tunnel FET improvement

Pei Yu Wang, Bing-Yue Tsui

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


The tunnel field-effect transistor (FET) is a promising candidate for use in ultralow-power applications because of its distinct operation principle, namely, band to band tunneling (BTBT). However, the ON-state current of the tunnel device is extremely low because of the poor tunneling efficiency of the BTBT. In this paper, a novel epitaxial tunnel layer (ETL) structure combining vertical tunneling orientation was proposed. The ETL structure performs more favorably than does the traditional lateral tunnel FET structure in an all-silicon device. By using low bandgap materials in the ETL, the ON-state BTBT current increases and an extremely low intrinsic OFF-state current is maintained because of the small low bandgap junction area. The onset voltage of the bipolar BTBT can also be postponed using ETL band engineering. The optimized parameters of the {\rm Si}-{\rm x}{\rm Ge}-{1\hbox{-}{\rm x}} ETL tunnel FET structure increase the ON-state current 10^{7}\hbox{-}108 times compared with that of the traditional lateral silicon tunnel FET. The minimal subthreshold swing (SS) and ON/OFF current ratio also improve, the SS decreases from 47 mV/decade to 29 mV/decade, and the ON/OFF current ratio increase from 105 to 1010. In this paper, the effects of the ETL parameters on device performance are discussed in detail.

Original languageEnglish
Article number6663625
Pages (from-to)4098-4104
Number of pages7
JournalIEEE Transactions on Electron Devices
Issue number12
StatePublished - 1 Dec 2013


  • Band to band tunneling
  • epitaxial tunnel layer (ETL)
  • silicon-germanium({\rm Si}-{\rm x}{\rm Ge}-{1\hbox{-}{\rm x}})
  • subthreshold swing (SS)
  • tunnel field-effect transistor
  • vertical tunneling

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