Variable-Channel Junctionless Poly-Si FETs: Demonstration and Investigation with Different Body Doping Concentrations

Jer Yi Lin, Chan Yi Tsai, Chiuan Huei Shen, Chun Chih Chung, Malkundi Puttaveerappa Vijay Kumar, Tien-Sheng Chao*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


In this letter, tri-gate polycrystalline silicon variable-channel junctionless transistors (VC-JLTs), which consist of a counter-doped p-type body below an n + active device layer, are successfully demonstrated to show a better performance compared with conventional tri-gate nanosheet (NS) JLTs. Because the potential barrier between the n-channel and p-body in the VC-JLT can be controlled by the gate, the effective conduction channel behaves as a 'variable' channel, in which the conduction thickness is thinner or thicker than the physical n + thickness for the OFF or ON state, respectively. Consequently, the VC-JLT can turn OFF more efficiently due to the enhanced volume depletion and turn ON with a smaller series resistance owing to the augmented conduction volume. In addition, for the first time, the impact of the body doping concentration is investigated and the performance sensitivities of VC-JLTs in terms of I ON , V T , S.S., and DIBL are discussed with respect to the dopant redistribution. Furthermore, the quality factor (I ON /S.S.) of the VC-JLT is also benchmarked with recently published poly-Si JLTs, showing that the proposed VC-JLT exhibits good S.S. and a record I ON , which makes it as a promising device for 3-D integrated nanoelectronics.

Original languageEnglish
Article number8417437
Pages (from-to)1326-1329
Number of pages4
JournalIEEE Electron Device Letters
Issue number9
StatePublished - 1 Sep 2018


  • body doping
  • junctionless (JL)
  • nanosheet (NS)
  • polycrystalline silicon
  • Variable channel (VC)


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