Impact of Substrate Resistance on Drain Current Noise in MOSFETs

Abstract

This paper identifies the physical origin and contribution mechanism of substrate induced channel thermal noise in MOSFETs. Resistance of the substrate generates potential fluctuations that in turn produce additive channel noise via the channel depletion capacitor. The additive noise may result in a frequency dependence of the drain current noise due to a pole associated with the Rsub-Cdepi network. Its bias and length dependencies conforms to those of reported excess noise, it thus may exaggerate the amount of the channel thermal noise factor.