The construction of a Focused Ion Beam(FIB) workstation is similar to that of an electron microscope. The probe is fixed on a multi-axis tilt stage located in a high-vacuum chamber. The ion column is connected to this chamber. Inside the column ions are generated, accelerated and focused. A liquid metal ion source acts as ion source (in most cases gallium or indium ions). It consists of a metal-coated tungsten needle.
Applying an electrical field the ions are extracted from the metal surface by field transmission.
A characteristic of liquid metal ion sources is their extremely high intensity (approx. 106A/cm²sr) and a small emission area (approx. 10nm). This small emission area is the basis for the strong focusing of the ion beam by the ion optical system integrated in the ion column.