Lack of spatial correlation in mosfet threshold voltage variation and implications for voltage scaling
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Drego_Lack-of-Spatial.pdf
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Author(s)
Boning, Duane S.
Drego, Nigel A.
Chandrakasan, Anantha P.
Date Issued
May 2009
Journal
IEEE Transactions on Semiconductor Manufacturing
Publisher
Institute of Electrical and Electronics Engineers
Citation
Drego, N., A. Chandrakasan, and D. Boning. “Lack of Spatial Correlation in MOSFET Threshold Voltage Variation and Implications for Voltage Scaling.” Semiconductor Manufacturing, IEEE Transactions on 22.2 (2009): 245-255. © 2009 IEEE
Version
Final published version
Abstract
Due to increased variation in modern process technology nodes, the spatial correlation of variation is a key issue for both modeling and design. We have created a large array test-structure to analyze the magnitude of spatial correlation of threshold voltage (VT) in a 180 nm CMOS process. The data from over 50 k measured devices per die indicates that there is no significant within-die spatial correlation in VT. Furthermore, the across-chip variation patterns between different die also do not correlate. This indicates that Random Dopant Fluctuation (RDF) is the primary mechanism responsible for VT variation and that relatively simple Monte Carlo-type analysis can capture the effects of such variation. While high performance digital logic circuits, at high VDD , can be strongly affected by spatially correlated channel length variation, we note that subthreshold logic will be primarily affected by random uncorrelated VT variation.
Subjects
variation
threshold voltage
Spatial correlation
MIT Department
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Massachusetts Institute of Technology. Microsystems Technology Laboratories
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Persistent DSpace Link
DOI of Published Version
http://dx.doi.org/10.1109/TSM.2009.2017645
