Simple estimation of the effect of hot-carrier degradation on scaled nMOSFETs

Abstract

The influence of parasitic charge at the Si–SiO2 interface on the characteristics of n-channel metal oxide semiconductor field effect transistors (nMOSFETs) scaled down to a feature size of 25 nm is studied. The results are that the impact of parasitic charge on threshold voltage and drain current degradation significantly decreases. Additionally, as the hot-electron injection current densities are lowered for scaled-down nMOS transistors, less charge build-up occurs. This opens the perspective to make use of alternative gate dielectrics even if they have a higher interface trap density. These materials offer the advantage of greater dielectric constants than silicon oxide, so that a physically thicker dielectric will limit the gate tunnelling current.