Gate Voltage Dependence of MOSFET Noise Statistics

In this letter, we present experimental and theoretical analysis of the gate voltage dependence of MOSFET noise variations. Under low gate overdrive, noise power variability as much as 12.2 dB is reported from a population of moderately sized FETs. However, the variability is reduced to 4.4 dB for the same population of devices at high gate overdrive. The relationship between inversion layer density within the vicinity of a trap and the trapped-charge-induced mobility fluctuation is investigated. The spatial gradient of the inversion layer profile is shown to impact the variability of noise. As the inversion layer becomes more uniform across the channel, noise variability is reduced. TCAD simulations and noise measurements are in agreement with the proposed theory.