Examines the effectiveness of opportunistic use of reverse body bias (RBB) to reduce leakage power during active operation, burn-in, and standby in 0.18 /spl mu/m single-V/sub t/ and 0.13 /spl mu/m dual-V/sub t/ logic process technologies. Investigates its dependencies on channel length, target V/sub t/, temperature and technology generation. Shows that RBB becomes less effective for leakage reduction at shorter channel lengths and lower V/sub t/ at both high and room temperatures, especially when target intrinsic leakage currents are high. RBB effectiveness also diminishes with technology scaling primarily because of worsening short-channel effects (SCE), particularly when target V/sub t/ values are low. A model is given that relates different transistor leakage components to full-chip leakage current, and is validated through test-chip measurements across a range of RBB values.