Atomistic Full-Band Simulations of Si Nanowire Transistors: Effects of Electron-Phonon Scattering

Mathieu Luisier, Network for Computational Nanotechnology and Birck Nanotechnology Center, Purdue University
Gerhard Klimeck, Network for Computational Nanotechnology and Birck Nanotechnology Center, Purdue University

Date of this Version

2009

Comments

preprint

Abstract

An atomistic full-band quantum transport simulator has been developed to study three-dimensional Si nanowire field-effect transistors (FETs) in the presence of electron-phonon scattering. The Non-equilibrium Green's Function (NEGF) formalism is solved in a nearest-neighbor sp(3)d(5)s* tight-binding basis. The scattering self-energies are derived in the self-consistent Born approximation to inelastically couple the full electron and phonon energy spectra. The band dispersion and the eigenmodes of the confined phonons are calculated using a dynamical matrix that includes the bond and angle deformations of the nanowires. The optimization of the numerical algorithms and the parallelization of the NEGF scheme enable the investigation of nanowire structures with diameters up to 3 nm and lengths over 40 nm. It is found that the reduction of the device drain current, caused by electron-phonon scattering , is more important in the ON-state than in the OFF-state of the transistor. Ballistic transport simulations considerably overestimate the device ON-currents by artificially increasing the charge injection mechanism at the source contact.

Discipline(s)

Nanoscience and Nanotechnology

 

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