Modeling approach for rapid NEGF-based simulation of ballistic current in ultra-short DG MOSFETs

Abstract

Multiscale simulation has to bridge the gap between device simulation, its effects in the atomic scale and the calculation of the device terminal voltages for circuit simulation. Iterative numerical solutions in device models significantly slow down the simulation. In this work a semi analytical non-equilibrium Green's function (NEGF) model for ultra-short DG MOSFETs is introduced, which turns the NEGF from an iterative numerical solution into a straightforward calculation. The benefit of using the NEGF is the physics-based consideration of quantum effects like the source-to-drain (SD) tunneling, which influences the device behavior in the sub 10nm region. Using mathematical approximations, the calculation time of the 1D NEGF is significantly reduced. The model is compared with NanoMOS TCAD simulation data and shows a good behavior for temperatures down to 75K and good agreement for channel lengths from 6 nm to 10 nm. Additionally, the model shows the electron density for the source and drain contacts at different energies.