Hierarchical approach to 'atomistic' 3-D MOSFET simulation

Asenov, A., Brown, A. R., Davies, J. H. and Saini, S. (1999) Hierarchical approach to 'atomistic' 3-D MOSFET simulation. IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 18(11), pp. 1558-1565. (doi: 10.1109/43.806802)

Abstract

We present a hierarchical approach to the 'atomistic' simulation of aggressively scaled sub-0.1-μm MOSFETs. These devices are so small that their characteristics depend on the precise location of dopant atoms within them, not just on their average density. A full-scale three-dimensional drift-diffusion atomistic simulation approach is first described and used to verify more economical, but restricted, options. To reduce processor time and memory requirements at high drain voltage, we have developed a self-consistent option based on a solution of the current continuity equation restricted to a thin slab of the channel. This is coupled to the solution of the Poisson equation in the whole simulation domain in the Gummel iteration cycles. The accuracy of this approach is investigated in comparison to the full self-consistent solution. At low drain voltage, a single solution of the nonlinear Poisson equation is sufficient to extract the current with satisfactory accuracy. In this case, the current is calculated by solving the current continuity equation in a drift approximation only, also in a thin slab containing the MOSFET channel. The regions of applicability for the different components of this hierarchical approach are illustrated in example simulations covering the random dopant-induced threshold voltage fluctuations, threshold voltage lowering, threshold voltage asymmetry, and drain current fluctuations.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Asenov, Professor Asen
• Authors: Asenov, A., Brown, A. R., Davies, J. H., and Saini, S.
• Subjects: T Technology > TK Electrical engineering. Electronics Nuclear engineering
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Research Group: Device Modelling Group
• Journal Name: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
• Publisher: Institute of Electrical and Electronics Engineers
• ISSN: 0278-0070
• Copyright Holders: Copyright © 1999 Institute of Electrical and Electronics Engineers
• First Published: First published in IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems 18(11):1565-1558
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher