The impact of acoustic and optical-phonon scateringon on the performance of CNT-FETs is investigated using a full-quantum transport model within the NEGF formalism. Different gate lengths, dielectric materials and chiralities are considered. It is shown that the use of a high-k dielectric lowers the off-current dominated by phonon-assisted band-to-band tunneling. The device scalability is demonstrated: with the oxide thickness fixed to 1.5 nm, good performance is obtained with 15 nm and 10 nm gate lengths with SiO_2 and HfO_2 gate dielectrics, respectively. The role of phonon scattering in CNT-FETs of different chiralities is investigated for the HfO_2 devices. A similar analysis has also been carried out for source/drain underlp geometries. The results confirm that the calculation of the off-currents and delay times is strongly influenced by phonon scattering.
Phonon-scattering effects in CNT-FETs with different dimensions and dielectric materials / R. Grassi; S. Poli; S. Reggiani; E. Gnani; A. Gnudi; G. Baccarani. - In: SOLID-STATE ELECTRONICS. - ISSN 0038-1101. - STAMPA. - 52:(2008), pp. 1329-1335. [10.1016/j.sse.2008.04.010]
Phonon-scattering effects in CNT-FETs with different dimensions and dielectric materials
GRASSI, ROBERTO;POLI, STEFANO;REGGIANI, SUSANNA;GNANI, ELENA;GNUDI, ANTONIO;BACCARANI, GIORGIO
2008
Abstract
The impact of acoustic and optical-phonon scateringon on the performance of CNT-FETs is investigated using a full-quantum transport model within the NEGF formalism. Different gate lengths, dielectric materials and chiralities are considered. It is shown that the use of a high-k dielectric lowers the off-current dominated by phonon-assisted band-to-band tunneling. The device scalability is demonstrated: with the oxide thickness fixed to 1.5 nm, good performance is obtained with 15 nm and 10 nm gate lengths with SiO_2 and HfO_2 gate dielectrics, respectively. The role of phonon scattering in CNT-FETs of different chiralities is investigated for the HfO_2 devices. A similar analysis has also been carried out for source/drain underlp geometries. The results confirm that the calculation of the off-currents and delay times is strongly influenced by phonon scattering.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
