Owing to the development of new ion source technology, users of focused ion beams (FIBs) have an increasingly wide array of uniquely capable platforms to choose from. Specifically, the new ion sources are able to offer superior performance in several applications when compared with the industry-standard Ga+ liquid metal ion source. FIBs equipped with an inductively coupled plasma (ICP) ion source are better equipped to carry out large volume milling applications by providing up to 1 µA to 2 µA of 30 keV Xe+ ions focused into a sub-5um spot. However, ICP FIBs are presently limited to 25-30 nm imaging resolution at 1pA. The Gas Field Ionization Source (GFIS) relies upon an ion source that is the size of a single atom on the emitter, and correspondingly gains a high brightness through its very small source size. The high brightness allows the GFIS to produce a very small focused probe size (less than 0.35 nm for helium and <1.9 nm for neon), but with comparatively small beam currents (less than 2 pA). Other ion sources still being developed, such as the Cs+ Low Temperature Ion Source (LoTIS), may enable high performance nanomachining with its projected sub-nm focal spot size at 1 pA as well as integrated secondary ion mass spectrometry (SIMS) capabilities.
Citation: MRS Bulletin
Pub Type: Journals
ion sources, focused ion beams, inductively coupled plasma, gas field ionization source, low-temperature ion source