Effects of the gate dielectric nitridation on the flicker (1/f) noise characteristics of submicron metal oxide semiconductor field effect transistors (MOSFETs) are reported. Low‐frequency (1/f) noise measurements on nitrided and non‐nitrided gate oxide MOSFETs of the same geometry have been carried out, showing different noise behavior with respect to the flicker noise amplitude and bias dependence. It is found that gate oxide nitridation not only increases the flicker noise amplitude, but also enhances the correlated mobility noise mechanism. The two orders of magnitude higher noise measured in nitrided structures is consistent with the approximately two orders of magnitude increase of the nitrided gate conductance reported in the literature. ©1995 American Institute of Physics.