  This brief reports the analytical modeling and measurements of the inflection
in the MOSFET transfer characteristics at cryogenic temperatures. Inflection is
the inward bending of the drain current versus gate voltage, which reduces the
current in weak and moderate inversion at a given gate voltage compared to the
drift-diffusion current. This phenomenon is explained by introducing a Gaussian
distribution of localized states centered around the band edge. The localized
states are attributed to disorder and interface traps. The proposed model
allows to extract the density of localized states at the interface from the dc
current measurements.
