Fast Estimation of NBTI-Induced Delay Degradation Based on Signal Probability

Song BIAN  Michihiro SHINTANI  Masayuki HIROMOTO  Takashi SATO  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E99-A   No.7   pp.1400-1409
Publication Date: 2016/07/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E99.A.1400
Type of Manuscript: Special Section PAPER (Special Section on Design Methodologies for System on a Chip)
NBTI,  reliability,  static timing analysis,  timing characterization,  aging-aware timing library,  

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As technology further scales semiconductor devices, aging-induced device degradation has become one of the major threats to device reliability. Hence, taking aging-induced degradation into account during the design phase can greatly improve the reliability of the manufactured devices. However, accurately estimating the aging effect for extremely large circuits, like processors, is time-consuming. In this research, we focus on the negative bias temperature instability (NBTI) as the aging-induced degradation mechanism, and propose a fast and efficient way of estimating NBTI-induced delay degradation by utilizing static-timing analysis (STA) and simulation-based lookup table (LUT). We modeled each type of gates at different degradation levels, load capacitances and input slews. Using these gate-delay models, path delays of arbitrary circuits can be efficiently estimated. With a typical five-stage pipelined processor as the design target, by comparing the calculated delay from LUT with the reference delay calculated by a commercial circuit simulator, we achieved 4114 times speedup within 5.6% delay error.