The impact of NBTI effect on combinational circuit: Modeling, simulation, and analysis

Wenping Wang, Shengqi Yang, Sarvesh Bhardwaj, Sarma Vrudhula, Frank Liu, Yu Cao

Research output: Contribution to journalArticlepeer-review

249 Scopus citations


Negative-bias-temperature instability (NBTI) has become the primary limiting factor of circuit life time. In this paper, we develop a hierarchical framework for analyzing the impact of NBTI on the performance of logic circuits under various operation conditions, such as the supply voltage, temperature, and node switching activity. Given a circuit topology and input switching activity, we propose an efficient method to predict the degradation of circuit speed over a long period of time. The effectiveness of our method is comprehensively demonstrated with the International Symposium on Circuits and Systems (ISCAS) benchmarks and a 65-nm industrial design. Furthermore, we extract the following key design insights for reliable circuit design under NBTI effect, including: 1) During dynamic operation, NBTI-induced degradation is relatively insensitive to supply voltage, but strongly dependent on temperature; 2) There is an optimum supply voltage that leads to the minimum of circuit performance degradation; circuit degradation rate actually goes up if supply voltage is lower than the optimum value; 3) Circuit performance degradation due to NBTI is highly sensitive to input vectors. The difference in delay degradation is up to 5 for various static and dynamic operations. Finally, we examine the interaction between NBTI effect, and process and design uncertainty in realistic conditions.

Original languageEnglish (US)
Article number5031899
Pages (from-to)173-183
Number of pages11
JournalIEEE Transactions on Very Large Scale Integration (VLSI) Systems
Issue number2
StatePublished - Feb 2010


  • Duty cycle
  • Input pattern
  • Negative bias temperature instability (NBTI)
  • Performance degradation
  • Speed
  • Supply voltage
  • Temperature

ASJC Scopus subject areas

  • Software
  • Hardware and Architecture
  • Electrical and Electronic Engineering


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