Aging-Aware Timing Analysis

With the down-scaling of CMOS technology into deep nanoscale era, the NBTI effect becomes stochastic due to its widely distributed defect parameters leading to more non-determinism in the functionality of the deeply scaled circuits. This chapter presents a framework to comprehensively investigate the combined effect of stochastic NBTI and process variation on the performance of the VLSI design at circuit level, by abstracting atomistic NBTI models (for the stochastic behavior) to the circuit timing analysis flow. Simulation results, performed in a 7 nm FinFET technology, show that the stochastic behavior of NBTI can result in a significant increase of the guardband. Moreover, our analysis reveals that stochastic NBTI and process variation should be considered together, otherwise it can lead to a major overestimation of the mean value of the delay degradation. The rest of the chapter is organized as follows. First, the motivation and contribution of this chapter are briefly discussed in Sect. 14.1. Next, the related work is discussed in Sect. 14.2. Afterwards, Sect. 14.3 introduces the flow of the proposed stochastic NBTI/process variation-aware timing analysis framework. Simulation results are presented in Sect. 14.4 and finally Sect. 14.5 concludes the chapter and summarizes the achievements.