Suppression of random dopant-induced threshold voltage fluctuations in sub-0.1-μm MOSFET's with epitaxial and delta-doped channels

Asenov, A. and Saini, S. (1999) Suppression of random dopant-induced threshold voltage fluctuations in sub-0.1-μm MOSFET's with epitaxial and delta-doped channels. IEEE Transactions on Electron Devices, 46(8), pp. 1718-1724. (doi: 10.1109/16.777162)

Abstract

A detailed three-dimensional (3-D) statistical 'atomistic' simulation study of fluctuation-resistant sub 0.1-μm MOSFET architectures with epitaxial channels and delta doping is presented. The need for enhancing the fluctuation resistance of the sub-0.1-μm generation transistors is highlighted by presenting summarized results from atomistic simulations of a wide range of conventional devices with uniformly doped channels. According to our atomistic results, the doping concentration dependence of the random dopant-induced threshold voltage fluctuations in conventional devices is stronger than the analytically predicted fourth-root dependence. As a result of this, the scaling of such devices will be restricted by the �intrinsic� random dopant-induced fluctuations earlier than anticipated. Our atomistic simulations confirm that the introduction of a thin epitaxial layer in the MOSFET's channel can efficiently suppress the random dopant-induced threshold voltage fluctuations in sub-0.1-μm devices. For the first time, we observe an �anomalous� reduction in the threshold voltage fluctuations with an increase in the doping concentration behind the epitaxial channel, which we attribute to screening effects. Also, for the first time we study the effect of a delta doping, positioned behind the epitaxial layer, on the intrinsic threshold voltage fluctuations. Above a certain thickness of epitaxial layer, we observe a pronounced anomalous decrease in the threshold voltage fluctuation with the increase of the delta doping. This phenomenon, which is also associated with screening, enhances the importance of the delta doping in the design of properly scaled fluctuation-resistant sub-0.1-μm MOSFET's.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Asenov, Professor Asen
• Authors: Asenov, A., 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 Electron Devices
• Publisher: Institute of Electrical and Electronics Engineers
• ISSN: 0018-9383
• Copyright Holders: Copyright © 1999 Institute of Electrical and Electronics Engineers
• First Published: First published in IEEE Transactions on Electron Devices 46(8):1718-1724
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher