Berlin 2005 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
HL: Halbleiterphysik
HL 45: Quantenpunkte und -dr
ähte: Transporteigenschaften II
HL 45.6: Vortrag
Montag, 7. März 2005, 16:15–16:30, TU P-N202
Impact of source/drain contacts on the performance of carbon nanotube field-effect transistors — •Joachim Knoch1, Siegfried Mantl1, Yu-Min Lin2, Z Chen2, Phaedon Avouris2, and Joerg Appenzeller2 — 1Institut fuer Schichten und Grenzflaechen, ISG-1, Forschungszentrum Juelich — 2IBM T.J. Watson Research Center, Yorktown Heights, NY10598 USA
Carbon nanotube field-effect-transistors (CNFETs)are attracting an increasing attention as building blocks of a future nano-electronics. In most of today’s CNFETs, metallic contacts are used made of e.g. titanium in contact with the nanotube. This contact plays the crucial role for carrier injection into the channel and it was found that CNFETs rather behave as Schottky barrier (SB) devices than conventional MOSFETs. Models capturing scaling aspects of CNFETs consequently consider a metallic electrode in direct contact with the nanotube. However, a closer look at CNFET data also reveals discrepancies between predictions of the existing SB-models and measured CNFET characteristics. A particularly obvious aspect is the often encountered asymmetric ambipolar or even unipolar appearance of Id−Vgs curves for thin gate oxides, an observation that cannot be explained by existing models. Here, we present an extended SB-model where current injection from the metal contacts into the channel does not happen directly but is mediated by a metal-poisoned nanotube underneath the contacts. With this model the experimentally observed IV characteristics can be reproduced and over a large gate voltage range.