Impact of channel carrier displacement and barrier height lowering on the low-frequency noise characteristics of surface-channel n-MOSFETs

Several unified low-frequency noise models for MOSFETs, developed in the past, combine carrier number fluctuations and correlated mobility fluctuations. The characteristics of the physical parameters in these models are reevaluated here, considering the channel carrier density and their displacement from the oxide-semiconductor interface with applied gate and body bias. The lowering of the oxide-semiconductor tunneling barrier with increasing gate bias is also considered for noise calculations. Experimental results are reported for n-MOSFETs to compare with the calculated low-frequency noise considering these effects. Including the oxide-semiconductor barrier height lowering and average displacement of channel carriers in the conventional correlated low-frequency noise model, the bias and geometry dependence of 1/f noise is explained quantitatively.