Full-3D real-space treatment of surface roughness in double gate MOSFETs

Author

Buran, Claudio ; Pala, Marco G. ; Poli, Stefano ; Mouis, Mireille

Author_Institution

IMEP-LAHC Grenoble INP MINATEC, Grenoble

fYear

2009

fDate

18-20 March 2009

Firstpage

47

Lastpage

50

Abstract

We analyze the effects of surface roughness on double gate (DG) MOSFETs by means of a full-3D real-space self-consistent Poisson-Schrodinger algorithm within the non equilibrium Green´s function (NEGF) formalism. We include periodic (Cauchy) boundary conditions along one of the transverse directions, whereas Dirichlet conditions are imposed along the vertical one. Surface roughness (SR) is included via a random generation of spatial fluctuations obeying an exponential autocorrelation law, and transfer characteristics are computed for different values of the root mean square (RMS) of such fluctuations. Simulation results show an impact of SR on the drain current and a shift of the threshold voltage proportional to the RMS. Quasi-ballistic transport is analyzed by means of backscattering coefficient. This is found to be limited by subband fluctuations at low inversion charge density and by mode-mixing at large one.

Keywords

Green´s function methods; MOSFET; Poisson equation; Schrodinger equation; surface roughness; Dirichlet conditions; backscattering coefficient; double gate MOSFET; drain current; exponential autocorrelation law; full-3D real-space self-consistent Poisson-Schrodinger algorithm; inversion charge density; mode-mixing; nonequilibrium Green´s function; periodic Cauchy boundary conditions; quasiballistic transport; subband fluctuations; surface roughness; threshold voltage shift; transfer characteristics; Algorithm design and analysis; Boundary conditions; Character generation; Fluctuations; Green´s function methods; MOSFETs; Rough surfaces; Strontium; Surface roughness; Surface treatment;

fLanguage

English

Publisher

ieee

Conference_Titel

Ultimate Integration of Silicon, 2009. ULIS 2009. 10th International Conference on

Conference_Location

Aachen

Print_ISBN

978-1-4244-3704-7

Type

conf

DOI

10.1109/ULIS.2009.4897536

Filename

4897536