FIB: Focused Ion Beam
Definition:A technique used in materials science, semiconductor industry, biology for deposition and ablation of materials.
Explanation:FIB functions in a similar fashion to a scanning electron microscope. Instead of using a beam of electrons, a focused beam of ions (usually gallium) is applied in FIB systems. This can be carried out at low beam currents for imaging or high beam currents for milling. As shown in the figure below, a focused ion beam hits the sample surface and sputters (removes) a small amount of target material. Secondary ions (or atoms) leave the surface together with secondary electrons and electromagnetic radiation. As the focused ion beam rasters on the sample surface, the signal from the sputtered ions/atoms or secondary electrons is collected to form an image. At higher beam currents, a larger amount of target material can be removed by sputtering, allowing for precision milling of the specimen down to a sub micrometer or even a nanoscale.

FIB is often used in the semiconductor industry to patch or modify an existing semiconductor device. A very common use of FIB technology is sample preparation for transmission electron microscopy (TEM) and more recently atom probe tomography (→APT). The TEM requires very thin samples, typically less than 100 nm. Compared to standard ion milling, nanoscale resolution of the FIB allows for the exact region of a specimen to be chosen for analysis. FIB is also applied for secondary ion mass spectroscopy as well as ion beam induced deposition.
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The principle of FIB.
SFB-Link:FIB is used for TEM and APT sample preparation.
References:L. A. Giannuzzi and F. A. Stevie, Micron 30, 197 (1999)