Modelling of scaled-down MOS transistors

Short-channel MOS transistors exhibit a drain current saturation behaviour different from that of longer channels. By comparing measured and calculated characteristics it is shown that the current increase can be successfully interpreted as a threshold voltage shift proportional to the drain voltage. A circuit model is derived which takes into account the above effect and includes an improved saturation mechanism. Compared with existing models the present one yields smaller deviations between measured and calculated characteristics and does not need non-physical parameters values.