An experimental study on channel backscattering in high-k/metal gate nMOSFETs

Quasi-ballistic transport in nanoscale high-k/metal gate nMOSFETs is investigated by RF S-parameter analysis. A simple experimental method based on RF S-parameter is used for direct extraction of device parameters (Leff, Cgc, RSD) and the effective carrier velocity (veff) from targeted short channel devices. The ballistic carrier velocity (vinj) at the top of the barrier near the source is determined by using the top-of-the-barrier model which self-consistently solves Schrödinger-Poisson equations. Combining the experimental extraction and the analytical top-of-the-barrier model, the backscattering coefficient (rsat) is calculated to assess the degree of the transport ballisticity for the high-k/metal gate nMOSFETs.