A Sequential Tunneling Model for Calculating Gate Leakage Current of Nanometer Metal-Oxide-Semiconductor Transistor

摘要

A direct tunneling gate current model for nanoscale metal-oxide-semiconductor field-effect transistor with dual-layer gate dielectrics is proposed. In this model, the polysilicon depletion effect and the quantum mechanical effect in the inversion layer are considered. Based on the sequential tunneling theory and Bardeen's transfer Hamiltonian formalism, the tunneling potential structure of electrons is divided into the two subsystems firstly, and then the Fermi golden rule is used to calculate the tunneling current density. The comparison between the experimental data and the calculated results confirms the availability of this model. The gate leakage currents through several dual-layer gate dielectrics (i.e., Si3N4/SiO2, Al2O3/SiO2, HfO2/SiO2 and La2O3/SiO2) are investigated numerically. The proposed model makes way for a simple and compact method of calculating direct tunneling current through multi-layer potential barrier structure.