Surface- potential- based model to study the subthreshold swing behavior including hot-carrier effect for nanoscale GASGAA MOSFETs

The proper design and simulation of future nanoelectronics digital devices requires accurate models of subthreshold behavior. The Gate All Around (GAA) MOSFET is considered one the most promising devices for downscaling below 50 nm. However, challenges still remain to resolve the important issues particularly concerning hot-carrier reliability and accurate device models for nanoscale circuit designs. Hot-carrier effects have been the major issues in the long-term stability of subthreshold performances in a nanoscale MOS transistor. Therefore, in this paper an analytical, surface-potential-based, model for the subthreshold swing of undoped GAA MOSFETs has been derived at low drain-source voltage based on an analytical solution of the two-dimensional Poisson equation (in cylindrical coordinates) with the hot carrier term included. The new model has been verified by comparison with 2-D numerical simulations.