For the first time, the drain-bias dependence of mean free path, predicted by previous Monte Carlo simulations, is experimentally confirmed in Si n FinFETs by using an improved formulation, considering the additional scatterings attributed to source/drain as well as the carrier degeneracy. This letter indicates that, for optimized Si n FinFETs, the carrier velocity and drive current still increase monotonically with decreasing channel length. However, the degradation in mean free path leads to the saturation in ballistic ratio (60%), resulting in quasi-ballistic transport for devices even with sub-20-nm channel length.
- Mean free path
- drain scattering
- long-range Coulomb interaction
- neutral defects
- quasi-ballistic transport