Dependence of resistivity on surface profile in nanoscale metal films and wires

TL;DR

This paper develops a quantum model to quantify how surface roughness at different wavelengths affects resistivity in nanoscale metal films and wires, providing insights for improving conductivity.

Contribution

It introduces a comprehensive quantum model that links surface roughness spectra to resistivity, enabling targeted surface engineering for better electrical performance.

Findings

Short-wavelength roughness dominates scattering in Cu films.

Specular scattering is achievable with RMS roughness below 0.7 nm.

Surface roughness at wavelengths under 100 nm significantly increases resistivity.

Abstract

We extend quantum models of nanowire surface scattering to incorporate bulk resistivity and extract an expression for the increased resistivity due to surface roughness. To learn how to improve conductivity, we calculate conductivity degradation from individual wavelengths of surface roughness, and show how these can be convolved to give resistivity for arbitrary surfaces. We review measurements from Cu films and conclude that roughness at short wavelengths (less than 100 nm) dominates scattering, and that primarily specular scattering should be achievable for RMS roughness below about 0.7 nm.