A Comparative Study of Surface-Roughness-Induced Variability in Silicon Nanowire and Double-Gate FETs

Author

Cresti, Alessandro ; Pala, Marco G. ; Poli, Stefano ; Mouis, Mireille ; Ghibaudo, Gérard

Author_Institution

Inst. de Microelectron., Electromagn. et Photonique, Lab. d´´Hyperfreq. et de Caracterisation, Univ. Joseph Fourier, Grenoble, France

Volume

58

Issue

8

fYear

2011

Firstpage

2274

Lastpage

2281

Abstract

We study the effect of surface roughness (SR) at the Si/SiO₂ interfaces on transport properties of quasi 1-D and 2-D silicon nanodevices by comparing the electrical performances of nanowire (NW) and double-gate (DG) field-effect transistors. We address a full-quantum analysis based on the 3-D self-consistent solution of the Poisson-Schrödinger equation within the coupled mode-space nonequilibrium Green function (NEGF) formalism. The influence of SR scattering is also compared with phonon (PH) scattering addressed in the self-consistent Born approximation. We analyze transfer characteristics, current spectra, density of states, and low-field mobility of devices with different lateral size, showing that the dimensionality of the quasi 1-D and 2-D structures induces significant differences only for thin silicon thicknesses. Thin NWs are found more sensitive to the SR-induced variability of the threshold voltage with respect to the DG planar transistors.

Keywords

Green´s function methods; Poisson equation; Schrodinger equation; approximation theory; elemental semiconductors; field effect transistors; nanowires; silicon; silicon compounds; DG planar transistor; NEGF formalism; Poisson-Schrödinger equation; Si; Si-SiO₂; coupled mode-space nonequilibrium Green function; current spectra; density of state; double-gate FET; field-effect transistor; full-quantum analysis; phonon scattering; quasi 1D silicon nanodevice; quasi 2D silicon nanodevice; self-consistent Born approximation; silicon nanowire; surface-roughness-induced variability; threshold voltage; transfer characteristic; transport property; Approximation methods; Logic gates; Phonons; Scattering; Silicon; Strontium; Transistors; Double-gate (DG); low-field mobility; nanowire (NW); nonequilibrium Green functions (NEGFs); phonon scattering; quantum transport; surface roughness (SR);

fLanguage

English

Journal_Title

Electron Devices, IEEE Transactions on

Publisher

ieee

ISSN

0018-9383

Type

jour

DOI

10.1109/TED.2011.2147318

Filename

5779717