Computation of drain and substrate currents in ultra-short-channel nMOSFET's using the hydrodynamic model

Abstract

The authors develop a robust and efficient numerical solution of the hydrodynamic model, which solves the energy balance equation, and compare predictions of this model, using one set of parameters, with experimental nMOSFET characteristics for a range of channel lengths down to ultrashort channels. The substrate current is calculated by direct integration of the energy distribution function, which uses the computed temperature to obtain the number of high energy electrons. The drain current calculated using this method is accurate for a range of channel lengths and biases, and correctly predicts the observed enhanced transconductance for ultrashort-channel devices. The substrate current matches the experimental data for a range of channel lengths and biases above threshold with one set of physically reasonable parameters.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>