By Topic

Variability in Si Nanowire MOSFETs Due to the Combined Effect of Interface Roughness and Random Dopants: A Fully Three-Dimensional NEGF Simulation Study

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

5 Author(s)
Martinez, A. ; Dept. Electron. & Electr. Eng., Univ. of Glasgow, Glasgow, UK ; Seoane, N. ; Brown, A.R. ; Barker, J.R.
more authors

In this paper, we study the impact of surface roughness and its combination with random discrete dopants on the current variability in nanometer-scale nanowire metal-oxidesemiconductor field-effect transistors. It is shown that these two variability sources cannot be regarded as independent in their effect on transport. Interface roughness results in body thickness fluctuations and scattering, which degrades transistor performance. This paper extends our previous study, in which we concentrated only on the impact of random discrete dopants in the source/drain regions in the same type of devices that lead to current variability. We have simulated ensembles of 30 devices, which differ due to the physical manifestation of the variability sources, including the detailed microscopic pattern of the interface in the channel and the number and configuration of discrete dopants in the source/drain regions. An ensemble of devices, with rough interfaces and continuous doping, has first been simulated to differentiate the effect of the interface roughness from the random discrete dopants before considering the combined case. It was found that, in some peculiar cases, the surface roughness induced resonant structures inside the device, producing quasibound states. These resonant states are similar to those related to individual discrete dopants in our previous study. We found that there is strong correlation between the microscopic patterns of the interface and the device performance due to the non-self-averaging of the microscopic features, which plagues devices with small channel lengths. The surface roughness induces a threshold voltage shift and decreases the ON-current of the device due to scattering. In the fully 3-D nonequilibrium Green's function formalism, both effects are combined in the propagation of the electron wave through the device. We have extracted the surface roughness related scattering contribution and estimated the associated mobility.

Published in:

Electron Devices, IEEE Transactions on  (Volume:57 ,  Issue: 7 )