1 / 18

D.L. Pulfrey

Carbon Nanotube Field-Effect Transistors: Critique of High-Frequency Performance. D.L. Pulfrey. Department of Electrical and Computer Engineering University of British Columbia Vancouver, B.C. V6T1Z4, Canada. pulfrey@ece.ubc.ca. http://nano.ece.ubc.ca. L.C. Castro D.L. John Li Chen.

clarke
Download Presentation

D.L. Pulfrey

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Carbon Nanotube Field-Effect Transistors: Critique of High-Frequency Performance D.L. Pulfrey Department of Electrical and Computer Engineering University of British Columbia Vancouver, B.C. V6T1Z4, Canada pulfrey@ece.ubc.ca http://nano.ece.ubc.ca L.C. Castro D.L. John Li Chen

  2. Carbon Nanotubes • Hybridized carbon atom  graphene monolayer  carbon nanotube 1s orbital, 2e- sp2 hybridized orbital, 3e-(-bonds) 2p orbital, 1e-(-bonds) • High mobility – quasi-1D, low m*, no surface states • Small SCE - coaxial geometry L.C. Castro

  3. Employment of metallic CNTs T. Iwai et al., (Fujitsu), 257, IEDM, 2005

  4. Fabricated Carbon Nanotube FETs 300 nm SB-CNFET A. Le Louarn et al., APL, 90, 233108, 2007 Single-tube drawbacks: Imax~ A Zout ~ k 80nm C-CNFET A. Javey et al., Nano Lett., 5, 345, 2005

  5. High-frequency Carbon Nanotube FET A. Le Louarn et al., APL, 233108, 2007

  6. Experimental results for fT "Ultimate"

  7. Carbon nanotube FETs: model structures SB-CNFET K. Alam et al., APL, 87, 073104, 2005 C-CNFET D.L. Pulfrey et al., IEEE TNT, 2007

  8. Ballistic transport

  9. vsig and SD

  10. SB-CNFET: summary of predictions "Ultimate"

  11. C-CNFET: summary of predictions (July 2007)

  12. C-CNFET: summary of predictions (latest)

  13. Regional delay times Energy where most ∂Q occurs 7.6 THz D.L. Pulfrey et al., IEEE TNT, 2007 D.L. John et al., WOCSDICE, 2007

  14. FET QG+qg _ + + + + _ + _ QD+qd QS+qs qe + _ + + _ + qe QB+qb QC+qc Image charges in transistors BJT _ + _ + _ + QB QC FET: qg |qe| BJT: qb < |qe|

  15. Q(E,z) in CNFETs C-CNFET SB-CNFET -5.5eV Insignificant resonance in channel

  16. Comparison of vband:Si NW, Si planar and CNT (11,0) CNT Tight-binding Si NW and planar Si J.Wang et al., APL, 86, 093113, 2005 vb,max (CNT) higher by factor of ~ 5

  17. CN oxide Gate Si MOSFET and CNFET: comparison S. Lee et al., IEDM, 241, 2005

  18. Conclusions • Multi-channel CNFETs needed for high current and for impedance matching. • HF performance appears to be ultimately limited by vb,max. • CNs have a vb,max advantage over Si of ~ 5 times. • This could lead to a gm advantage (in C-CNFETs). • Translating this advantage into superior fT and fmax will necessitate keeping CGG low, which may be a technological issue. • Seek applications not suited to Si.

More Related