The influence of localized states on gate tunnel currents-modeling and simulation

In the numerical simulation of ultra-small MOSFETs with oxide thicknesses in the range 2 to 4 nm, gate leakage currents have to be modeled on a sound physical basis. The main mechanisms apart from oxide non-idealities are direct and resonant tunneling (Fowler-Nordheim tunneling at large biases). Applying a self-consistent simulation of direct tunneling using a fully analytical model, we study the impact of the confinement of carriers in the inversion channel (quasi 2D states) on the size of the direct tunnel current. This is achieved with a Poisson-Schrodinger solver integrated with the device simulator DESSIS-ISE, and by applying Bardeen´s perturbational method.