Gate replacement techniques for simultaneous leakage and aging optimization

As technology scales, the aging effect caused by Negative Bias Temperature Instability (NBTI) has become a major reliability concern for circuit designers. On the other hand, reducing leakage power remains to be one of the design goals. Because both NBTI-induced circuit degradation and standby leakage power have a strong dependency on the input vectors, Input Vector Control (IVC) technique may be adopted to mitigate leakage and NBTI. However, IVC technique is in-effective for larger circuits. Therefore, in this paper, we propose two fast gate replacement algorithms together with optimal input vector selection to simultaneously mitigate leakage power and NBTI induced circuit degradation: Direct Gate Replacement (DGR) algorithm and Divide and Conquer Based Gate Replacement (DCBGR) algorithm. Our experimental results on 20 benchmark circuits at 65nm technology node reveal that: 1) Both DGR and DCBGR algorithms outperform pure IVC about on average 20% for three different object functions: leakage power reduction only, NBTI mitigation only, and leakage/NBTI co-optimization. 2) The DCBGR algorithm leads to better optimization results and save on average 100X runtime compared with the DGR algorithm.