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 (L_eff, C_gc, R_SD) and the effective carrier velocity (v_eff) from targeted short channel devices. The ballistic carrier velocity (v_inj) 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 (r_sat) is calculated to assess the degree of the transport ballisticity for the high-k/metal gate nMOSFETs.