In this paper, a computationally efficient model using evanescent mode analyses for solving two-dimensional Poisson's equation in the channel region has been presented for an accurate prediction of (a) surface potential, (b) electric field, (c) I DS -V GS characteristics, (d) threshold voltage, (e) transconductance and (f) drain conductance of insulated shallow extension MOSFET. The important short channel device features, drain induced barrier lowering (implemented via the voltage doping transformation method), channel length modulation and velocity saturation/overshoot, have been included in the model in a physically consistent manner. The obtained analytical results have been verified by ATLAS 2D: device simulation software.