Noise Sources in Bulk CMOS

The noise behavior of bulk CMOS devices is dominated primarily by two noise sources: thermal noise and flicker (1/f) noise. Other sources that are sometimes present in the noise spectrum are shot noise, generation/recombination noise, and “popcorn” noise. Of these sources, thermal noise and shot noise are physically fundamental to the operation of the device and are always present. The quality of the manufactured device (the number of defects in the bulk silicon, in the gate oxide, and in the various interfaces) determines the level of generation/recombination noise and popcorn noise. It is probable that flicker noise appears through both quality-dependent and fundamental noise processes.