A model for the submicrometer n-channel deep-depletion SOS/MOSFET

We present a model which accurately predicts current characteristics of submicrometer n-channel deep-depletion SOS/MOSFET\´s over a wide range of operating voltages. The theory extends previous work [1] to obtain a computationally efficient device model which is applicable to VLSI circuit simulation. Several important aspects are incorporated. First, is the inclusion of mobility dependence on depth away from the Si-SiO2interface in the thin epitaxial film. This characteristic is used to simplify the two-dimensional Poisson equation in the velocity saturated region of the channel, even past the classical "pinchoff" point. Secondly, this analysis allows the calculation of avalanche multiplication and its effect on the drain current. Third is the calculation of additional charge contribution in the velocity saturated portion of the channel caused by drain-induced barrier lowering (DIBL). We apply the model to devices with channel lengths of 2.5, 1.5, 0.9, and 0.46 µm, comparing predicted drain currents to experimental values.