Calculation of Cu/Ta interface electron transmission and effect on conductivity in nanoscale interconnect technology

TL;DR

This paper models electron transmission at Cu/Ta interfaces to understand how barrier layers affect nanoscale interconnect conductivity, revealing significant decreases in conductivity due to interface scattering.

Contribution

It introduces a semiclassical model to predict the impact of Cu/Ta interface scattering on interconnect conductivity, aligning with experimental observations.

Findings

Barrier layers significantly reduce conductivity.

The model accurately predicts scattering effects.

Interface scattering explains resistivity increases.

Abstract

Resistivity augmentation in nanoscale metal interconnects is a performance limiting factor in integrated circuits. Here we present calculations of electron scattering and transmission at the interface between Cu interconnects and their barrier layers, in this case Ta. We also present a semiclassical model to predict the technological impact of this scattering and find that a barrier layer can significantly decrease conductivity, consistent with previously published measurements.