With process scaling, leakage power reduction has become one of the most important design concerns. Multi-threshold techniques have been used to reduce runtime leakage power without sacrificing performance. In this paper, we propose small biases of transistor gate-length to further minimize power in a manufacturable manner. Unlike multi-Vth techniques, gate-length biasing requires no additional masks and may be performed at any stage in the design process. Our results show that gate-length biasing effectively reduces leakage power by up to 25% with less than 4% delay penalty. We show the feasibility of the technique in terms of manufacturability and pin-compatibility for post-layout power optimization. We also show up to 54% reduction in leakage uncertainty due to inter-die process variation in circuits when biased gate-lengths, versus only unbiased one, are used. Circuits selectively biased show much less sensitivity to both intra and inter die variations. Categories and Subject Desc...
Puneet Gupta, Andrew B. Kahng, Puneet Sharma, Denn