Derivation of drain current thermal noise for short-channel MOSFETs including the velocity saturation effect

Abstract

In this work, a physics-based drain current thermal noise model for short-channel MOSFETs was derived. The proposed model takes into account the velocity-saturation effect explicitly and the carrier heating effect implicitly in the gradual channel region. A diffusion noise source was used to model the local noise generated in a segment of the inversion layer macroscopically, and the impedance field was recalculated when considering the velocity saturation effect. Finally, the proposed model suggests that the increase in the thermal noise for short-channel MOSFETs originates dominantly from the channel length modulation effect.