Degradation of inversion layer electron mobility due to interface traps in metal-oxide-semiconductor transistors

Abstract

Degradation of inversion layer electron mobility during Fowler–Nordheim electron injection has been investigated using n-channel metal-oxide-semiconductor transistors. The change of the reciprocal effective mobility, Δ(1/μEFF), has been found to be linearly related to the generated interface trap density, ΔNit, at a given effective electric field normal to the Si/SiO2 interface. The effect of trapped charges in the oxide on the mobility degradation is rather insignificant, which is attributed to the location of trapped charges from the Si/SiO2 interface. The dependence of mobility degradation on inversion layer electron density has also been explained using a transport theory based on two-dimensional electron gas.