1/f noise in n-channel silicon-gate MOS transistors

It is found that equivalent gate noise power for l/f noise in n-channel silicon-gate MOS transistors at near zero drain voltage at room temperature is empirically described by two noise terms, which vary as
K_{1}(q/C_{ox}) (V_{G} -V_{T})/f and K_{2}(q/C_{ox})^{2}/f, where V_{G}
is gate voltage, V
T
is threshold Voltage, and C
ox
is gate-oxide capacitance per unit area. Unification of carrier-density fluctuation (McWhorter's model)and mobility fluctuation (Hooge's model) can account for the experimental data. The comparison between the theory and experiment shows that the carrier fluctuation term K
2
is proportional to oxide-trap density at Fermi-level. The mobility fluctuation term K
1
is correlated to K
2
, being proportional to
\radic K_{2}
. The origin of this correlation is yet to be clarified.