Observation of double peak in the substrate current versus gate voltage characteristics of n-channel metal-oxide-semiconductor field effect transistors

By employing sensitive current measurements at low drain voltages for n-channel metal-oxide-semiconductor field effect transistors with different channel dopings, substrate current versus gate voltage characteristics with two peaks were obtained for devices with low channel doping at 77 K. This differs from the single peak bell shaped curves reported in the literature. The data are analyzed and suggest that the second peak is due to the contribution of electron-electron interactions to the high energy tail of the electron energy distribution. Indirect contributions by the thermal tail of the electron energy distribution and ionized impurity scattering that make the second peak visible are also discussed. (C) 2001 American Institute of Physics.