Larger-than-V/sub dd/ forward body bias in sub-0.5V nanoscale CMOS

This paper examines the effectiveness of larger-than-V/sub dd/ forward body bias (FBB) in nanoscale bulk CMOS circuits where V/sub dd/ is expected to scale below 0.5V. Equal-to and larger-than V/sub dd/ FBB schemes offer unique advantages over conventional FBB such as simple design overhead and reverse body bias capability respectively. Compared to zero body bias, they improve process-variation immunity and achieve 71% and 78% standby leakage savings at iso performance and iso active power at room temperature. We also suggest a novel temperature-adaptive body bias scheme to control active leakage and achieve 22% and 40% active power savings at higher temperatures.