Comparison of two {1}/{f} noise models in MOSFETs

The noise expressions for the number fluctuation model and for the mobility fluctuation model of {1}/{f} in MOSFETs at low drain bias are derived and expressed in terms of the effective trap parameter [ N_T( E_f)] _eff/ ɛ and in Hooge's parameter α_H, respectively. It is indicated how the turn-on voltage V_T of the device and the carrier mobility μ can be evaluated from the characteristics; the two parameters can then be determined from the measured drain noise. Both parameters have modest values; either model might be correct, but the present measurements cannot discriminate between the models. Silicon on sapphire MOSFETs have values for these parameters that are a factor 200 larger than other devices.