Significance of Work Function Fluctuations in SiGe/Si Hetero-Nanosheet Tunnel-FET at Sub-3 nm Nodes

Narasimhulu Thoti, Yiming Li, Wen Li Sung

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12 Scopus citations

Abstract

This work highlights the work-function-fluctuation (WKF) of the strained Si&#x2080;.&#x2086;Ge&#x2080;.&#x2084; p-n-p-n tunneling field-effect transistor (TFET) using nanosheet geometry at sub-3 nm technology nodes. The reported work exploits 3000 samples to signify the key results of several dc factors such as ON- and OFF-state currents ( <formula> <tex>$I_{ON}$</tex> </formula> and <formula> <tex>$I_{OFF}$</tex> </formula> ), threshold voltage (<formula> <tex>$V_{th}$</tex> </formula> ), and the subthreshold swing (SS). Fewer WKFs are identified for higher metal grain number (MGN) due to the shaped low grain size. Collective average energy reduction of 10-15 meV as low with high MGN and 40-60 meV as high with low MGN for a group of metal-grains closer to the tunneling junction is observed. This huge impact of energy reduction proportionally affects electron transport due to reduction in tunneling length. High variability in <formula> <tex>$V_{th}$</tex> </formula> (&#x2265;15&#x0025;) is identified at progressively diminished MGN due to parabolic behavior of variation. Furthermore, marginal variation in SS, <formula> <tex>$I_{ON}$</tex> </formula> , and <formula> <tex>$I_{OFF}$</tex> </formula> are observed because of the WKF dependability over the subthreshold region of operation.

Original languageEnglish
JournalIEEE Transactions on Electron Devices
DOIs
StateAccepted/In press - 2021

Keywords

  • Band to band tunneling (BTBT)
  • Electric potential
  • Grain size
  • Junctions
  • Logic gates
  • metal grain number (MGN)
  • Metals
  • n-pocket
  • nanosheet
  • Si&#x2080;.&#x2086;Ge&#x2080;.&#x2084;
  • TFETs
  • threshold voltage
  • Tunneling
  • work function fluctuations (WKFs).

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