Equivalent Length Concept for Compact Modeling of Short-Channel GAA and DG MOSFETs

We present a way to analytically describe short-channel effects in cylindrical gate-all-around (GAA) MOSFETs with intrinsic or lightly-doped channels. For a given device dimension, the center and surface potentials (Φ c and Φ s) are correctly determined by using the conformal mapping technique for 2-D double-gate (DG) FETs. An equivalent channel length is used in a compact drain current model of a DG device, which thereby is modified to get results for a cylindrical GAA MOSFET. To verify the introduced equivalent correlation for different channel lengths and thicknesses we compare both potentials Φc and Φ s, the subthreshold swing (S sth) and the drain-induced barrier lowering (DIBL) of our new compact model with 3-D GAA MOSFET TCAD simulation data. In addition, we compare for one chosen device dimension the DC characteristics of our model with TCAD and measurement data.