Focused Ion Beams

Focused ion beam (FIB) is a technique used for site-specific analysis and fabrication of materials. The ion beam is produced from a liquid ion metal (such as Ga) source. In this chapter, we introduce the set up and the principles of an FIB system. The four basic functions of FIB-imaging, milling, etching/deposition and implantation - are discussed. Generally, FIB and scanning electron microscopy (SEM) are combined into one system to achieve the precise machining abilities of FIB with the high-resolution and lessdestructive SEM imaging. 3D real-time imaging and 3D nanostructure fabrication can be accomplished using FIB systems. FIB has been utilized for imaging and fabrication on semiconductors, metals, ceramic, polymers and biological materials. Here, we present the use of FIB in investigating the formation of protein nanospheres by evaporation-induced self-assembly. Finally, we introduce two limitations of FIB: surface damage and implantation, which may impact the quality of imaging and fabrication.