Enhanced electron transport by carrier overshoot in ultrascaled Double Gate MOSFETs

When the silicon film thickness of a DG-MOSFET is decreased, the electron transport is dominated by two opposite mechanisms: the intersubband modulation effect and the increase in the phonon scattering rate. We show that although the mobility is remarkably degraded by the phonon scattering, the electrons drift can profit from the velocity overshoot induced by the decrease in the conduction effective mass. This fact allows a more aggressive reduction in the device channel length in contrast to what is demonstrated considering only the low-field mobility behavior.