Equivalent input spectrum and drain current spectrum for 1/ƒ noise in short channel MOS transistors

Flicker noise in MOS transistors can be evaluated by measuring the spectrum S_ID of the drain current fluctuation or the spectrum Sve of an equivalent gate fluctuation. We show here that experimental variations of are in good agreement with g_m² by considering a model of the transconductance g_m which takes into account the variations of the channel carriers mobility with the surface electric field. The model agrees with the experimental results obtained on short channel MOS transistors which exhibit large variations of mobility with the gate voltage. The validity of physical interpretations of noise data on MOS transistors is examined.