Novel test sample for submicron ion-beam analysis

In order to determine the beam spot size, scan size and scanning properties of a nuclear microprobe system a novel test sample with nanometer structures for the use in submicron ion-beam analysis has been developed by the University of Leipzig and the Institute for Surface Modification (IOM). The test sample provides horizontally and vertically arranged periodic structures, which range from 4 mum to 150 nm in size. The structures have been produced in SiO2 and Ag for topographic and elemental contrast, respectively, using electron beam lithography and various etching techniques. The test sample was investigated with a scanning electron microscope (SEM) and the high-energy ion nanoprobe LIPSION. Due to the excellent definition of the edge profiles, the ion beam spot size can be directly derived from a line scan across an edge even in the submicron regime. The structures on the test sample also allow the determination of scan sizes of a few microns. Furthermore, a special nanostructure is proposed which makes it possible to image the beam current density within a submicron beam spot directly. (C) 2001 Elsevier Science B.V. All rights reserved.