X-ray and neutron reflectometry study of copper surface reconstruction caused by implantation of high-energy oxygen ions

TL;DR

This study uses neutron and X-ray reflectometry to analyze how high-energy oxygen ion implantation causes surface reconstruction and oxide formation on copper films, revealing a thin Cu2O layer formed due to atom mobilization.

Contribution

It provides detailed insights into the surface structural changes and oxide formation in copper films caused by high-energy oxygen ion implantation, combining neutron and X-ray techniques.

Findings

Formation of a 3 nm Cu2O surface layer at 30 keV implantation energy.

Surface layer density and stoichiometry close to Cu2O oxide.

Oxygen ion implantation induces copper atom mobilization leading to oxide formation.

Abstract

Combination of neutron and X-ray reflectometry was used to study the vertical structure of 100 nm-thin copper films with implanted oxygen ions of energy E = [10-30] keV and doses D=[0.2-5.4]x$10^{16}$ $cm^{-2}$. The study shows that oxygen ion implantation with an energy of E = 30 keV leads to the formation of a 3 nm thick layer on the surface. Density and copper/oxygen stoichiometry of the observed surface layer are close to $Cu_2O$ oxide. We attribute the $Cu_2O$ oxide formation to highly mobilized copper atoms generated by stimulated ion implantation.