A Surface Potential-Based Compact Model of n-MOSFET Gate-Tunneling Current

Abstract

Aggressive scaling of the gate-oxide thickness has made gate-tunneling current an essential aspect of MOSFET modeling. This work presents a novel physics-based compact model of gate current in the n-MOSFET. A simplified version of the Esaki-Tsu formula is developed to calculate the tunneling current density, in which the original integral is approximated to retain the essential physics without sacrificing computational efficiency required in a compact model. The proposed model is surface potential-based in both the channel and source/drain overlap regions. The channel component of the gate current is physically partitioned into the source and drain parts using a symmetrically linearized version of the charge-sheet model. The partition is implemented in analytical form and accounts for the drain bias dependence of the channel component. A small number of adjustable parameters is sufficient to reproduce the experimentally observed bias and geometry dependence of the gate current for several advanced processes.