Non-local microscopic view of signal propagation times in BJTs biased up to high currents

This paper presents a microscopic analysis of signal propagation delay in bipolar transistors featuring relevant non-equilibrium transport effects. First, the physical mechanisms responsible of signal delay are reviewed. A novel technique to extract signal delays from self-consistent Monte Carlo device simulations is presented. These results are then used for a physically based comparison between compact quasi-static delay formulas and more accurate particle simulations carried out over a broad range of collector currents.