Investigation of Rb+ milling rates using an ultracold focused ion beam

Abstract

Several ion source alternatives for current focused ion beam (FIB) systems have been studied to achieve higher brightness, including cold atom ion sources. However, a study of ultracold ions interacting with often used materials is seldom reported. Here, we investigate milling on several typical samples in a prototype ultracold Rb FIB system at 8.5 keV beam energy. For polycrystalline metallic substrates, such as Cu and Au, patterns milled by [Formula: see text] ions are observed to have reduced surface roughness but still high milling rates compared with those milled by [Formula: see text] ions. [Formula: see text] also shows similar sputter rates as 30 keV [Formula: see text] on semiconductor substrates GaAs and InP. Special cases for [Formula: see text] milling show that the [Formula: see text] ion beam has a [Formula: see text] faster sputter rate on diamond but a [Formula: see text] slower sputter rate on Al compared with a normal 30 keV [Formula: see text] ion beam. In general, an [Formula: see text] ion beam is shown to be suitable for nanostructuring of several basic materials.