Numerical investigation of excess RF channel noise in sub-100 nm MOSFETs

High-frequency simulations of channel-thermal noise in MOSFETs with gate-lengths of 40 nm, 80 nm, and 110 nm are presented. The simulated noise parameter gamma is a stronger function of the carrier transport model at shorter gate-lengths. Velocity saturation is necessary to produce a good match between the simulated and measured DC I-V characteristics using either the drift-diffusion or hydrodynamic transport models. However, in the presence of velocity saturation, the simulated noise is insufficient in explaining the observed excess noise. Hence, these physics-based device-level simulations point to the presence of a non-thermal RF noise source in the FET channel.