Modification of gold and titanium nanolayers using slow highly charged Xeq+ ions

Nanostructures created by irradiation of gold and titanium nanolayers with slow highly charged xenon ions are studied in this work. The gold and titanium nanolayers were prepared by sputtering deposition of the metals on polished quartz SiO2(100) or crystalline silicon Si(100) substrates. The irradiations were performed at room temperature using q×3.4keVXeq+ions from EBIT ion source, with charge state q=35 for gold and q=15–35 for titanium. The fluence of the ions on the irradiated samples was in the range of 7–12×109ions/cm2. Topographic atomic force microscopy (AFM) images of unmodified and ion-irradiated surfaces were measured. The AFM images of ion-irradiated surfaces clearly demonstrate the nanostructures in a form of hillocks created on the gold and titanium conducting surfaces as the result of an highly charged ion (HCI) impact. The ion charge state dependent measurements performed for titanium nanolayers suggest that the hillock formation is the due to kinetic energy deposition of HCI, while the role of potential energy seems to be less important. The hillock height and volume distributions are statistically analyzed. Additionally, for titanium the volume dependence on the charge state of the ions is presented. Possible influence of the nanolayer substrate on the hillock formation is discussed.