Dual-$V_t$ Allocation with Constraint on Minimum Ion Implantation Width

Abstract

As the technology continues to scales down, the minimum ion implantation width (MIW) is coming on as a new constraint for dual-$V_t$ design in sub-22nm technology. We define the MIW and find out the MIW value in future technology nodes. The new constraint causes leakage power overhead due to loss of high-$V_t$ allocations. To solve this new problem, we propose dual-$V_t$ design methods that minimize the leakage overhead without any MIW violation. We employ a three-step approach: expected power-based dual-$V_t$ allocation, $V_t$ reallocation, and MIW legalization. Experimental results show that proposed method can decrease one half on average compared to using only MIW legalization. Our method can allocate dual-$V_t$ without MIW violation increasing only 2.7% of leakage overhead on average.