Nanometer resolution three-dimensional microprobe RBS analyses by using a 200 kV focused ion beam system

Three-dimensional Rutherford backscattering (RBS) analyses have been achieved in the nanometer range for both lateral and vertical resolution using a 200 kV focused ion beam (FIB) system. The ion-optical design of the FIB microprobe RBS analysis system in Osaka University has been modified, and it is confirmed that the focusing performance of less than 20 nm lateral resolution is obtained with 300 keV Be2+ ion beam. Three-dimensional microprobe RBS analyses have been performed on a sample that has a structure with 2 layers of 10 nm thick Pt gratings separated vertically by a 25 nm thick SiO2 layer and offset 90 deg. each other. The Pt gratings consist of 0.5 μm width lines and 2 μm intervals. The RBS mapping and tomography images clearly show the three-dimensional fine structures of the sample