Focused Ion Beam (FIB)
The FIB technique shares many similarities to scanning electron microscopy (SEM), except a beam of gallium ions are used instead of forming a beam of electrons as in SEM. As shown in Fig. 15, gallium ions are pulled off the source using a high voltage extractor. This beam is collimated and focused using conventional ion optics. As in SEM, the gallium ions impinging on the sample lead to secondary electron emission which can be detected and utilized as a contrast mechanism for image formation. In addition, the momentum carried by the heavy gallium ions can mill the sample through a sputtering process. Therefore, using the Micrion FIB located in our laboratory, we can image and mill conductive and non-conductive samples with 10 nm resolution.
Below shows a near-field fiber optic probe before and after modification using the FIB shown above.