Physics of High-Frequency Noise in Insulated Gate Field-Effect Transistors

Abstract

A physical understanding of both intrinsic and extrinsic noise mechanisms in an IGFET is developed. Intrinsic noise mechanisms fundamental to device operation include channel thermal noise, induced gate noise and induced substrate noise. While the effect of channel thermal noise is observable at zero drain-to-source voltage, the induced gate and substrate noise do not manifest themselves under these conditions. However, the attendant fluctuations in the channel charge are observable by the passage of electric current through the device. Extrinsic noise mechanisms manifested due to structural evolution of the MOSFET include the distributed gate resistance noise, distributed substrate resistance noise, bulk charge effects, substrate current super-shot noise and gate current noise. Where possible, methods of suppression of these mechanisms are also highlighted.