Compact Modeling Framework for Short-Channel DG and GAA MOSFETs
H. Børli, S. Kolberg and T.A. Fjeldly
Norwegian University of Science and Technology, NO
device modeling, MOSFETs, multigate, nanoscale
To achieve sufficient accuracy in the compact modeling of short-channel, nanoscale DG and GAA MOSFETs, the multi-dimensionality of the body potential and the electronic charge distribution has to be accurately described. In sub-threshold, the device electrostatics is dominated by capacitive coupling between the electrodes. For the DG MOSFET, the 2D Laplace's equation can be conveniently solved by conformal mapping techniques, yielding analytical results. We show that the DG results can be successfully applied to the GAA MOSFET as well, by performing an appropriate device scaling to compensate for the difference in gate control between the two devices. This is described in terms of the characteristic longitudinal field penetration lengths of the DG and GAA geometries. Near and above threshold, the influence of the electronic charge is taken into account in a precise, self-consistent procedure. In strong inversion, the electronic charge dominates the device behavior, which approaches that of long-channel devices. Modeled electrostatics and drain currents have been verified against numerical simulations. Since no fitting parameters are used, the models are scalable over a wide range of geometric and material combinations. From this modeling framework, precise SPICE-compatible models can be derived.
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Nanotech 2007 Conference Program Abstract