Three-dimensional surface analysis system using a compact nuclear microprobe

A nondestructive three-dimensional Rutherford backscattering spectroscopy (RBS) and medium energy ion scattering (MEIS) analysis system with a compact 200 kV focused ion beam column has been developed. A liquid metal ion source (LMIS) such as lithium and/or beryllium (from Au/Si/Be eutectic alloy) was mounted on the short column. A high-vacuum sample chamber with a six-axis goniometer stage and an electrostatic toroidal analyzer for channeling and RBS analysis was connected to the acceleration column. The beam spot size was evaluated by microprobe-induced secondary electron image and a knife edge method using a thin gold pattern on a Si wafer. The beam current of 47 pA was obtained with a beam-spot diameter of 80 × 100 nm ² for 400 keV Be ⁺⁺ microprobes.