Short-Channel-Effect Modeling of DG-FETs Using Voltage-Doping Transformation Featuring FD/PD Modes

The virtual-cathode approach to modeling short-channel effects in deep-nanoscaled MOSFETs (with gate length of less than 25 nm) is increasingly viewed as a vital means in MOS compact modeling. To achieve analytical solution to the 2-D Poisson´s equation, the voltage-doping transformation is adopted to map 2-D electrostatics, including drain-induced barrier lowering, into an equivalent 1-D form at the point of virtual cathode. To accommodate both full-depletion and partial-depletion operation modes, contributions to space charge from electrons and holes are all considered. Models for subthreshold swing and threshold-voltage rolloff are further developed, and the accuracy of the overall model is verified through numerical device simulation.