Low-frequency noise (1 Hz–100 KHz) measurements have been performed on twelve n-MOSFETs with 5 &mgr;m width and 0.23–10 &mgr;m varying lengths. TheSi-SiO2interface state density computed from the noise measurements using the long-channel McWhorter Theory was found to be about two orders of magnitude lower than that measured through the I-V characteristics using the sub-threshold swing. This is most likely due to the fact that I-V characteristics probe to the fast interface states while noise is affected by the slower states further into the oxide. This effect might be compounded by the thinness of the oxide layer. The drain current power spectral density was found to vary inversely with effective channel length,SI∝Leff−3at low drain voltages, but showed a higher dependence,SI∝Leff−4,at higher drain voltage values for short channel devices. This is believed to be due to the channel shortening effect caused by the depletion region of the drain and the additional g-r noise generated by the same depletion region. Three H-SPICE models have been implemented to analyze the noise. Limitations of these models for short channel devices are discussed. ©1999 American Institute of Physics.