Ion beam analysis of light elements in nanoporous surfaces produced by single- and multiple-energy helium ion implantation

Helium ion implantation into surfaces is used to form nanoporous cavity structures at high dose levels. Such cavity structures have unique features which offer potential for applications. For some applications, it is necessary to produce cavity layers that extend to the surface to enhance the ingress of selected dopant atoms. Here we investigate a method based on using a He-implantation protocol (employing a combination of He energies and doses) to produce nanoporous layers that intersect the surface. Titanium and other targets are implanted with He to several different dose levels and at several different energies. Implantations employing several different He energies in sequence are also investigated. Light atom depth profiles are determined by heavy ion elastic recoil detection analysis (HERDA). Non-resonant nuclear reaction analysis is used to verify the absolute concentrations of carbon, nitrogen and oxygen. RBS is used to depth profile the corresponding heavy target elements. Selected results, chosen to highlight the potential of HERDA and other ion beam analysis techniques in this type of study, are presented