Focused Ion Beam (FIB): More than Just a Fancy Ion Beam Thinner

Abstract

Listen

Translate article

The potential utility of FIB for routine (and novel) applications has come to forefront recently due to advances in ion optics which now allow formation of focused ion probe of better than ∼10-20 nm containing current density exceeding several A/cm2, with a liquid metal source (typically Gallium). The small ion probe size, coupled with shallow sputtering depth - yet high sputtering yield of ions, has opened several opportunities in machining, lithography and ion-assisted deposition.[1-3] These developments, including automation, multi-specimen stages, cross-compatible specimen holders for FIB/TEM/SEM, use of in-situ electron beam (so-called dual beam), coupled with innovations such as the “lift-off” process[4], have provided an invaluable set of tools for microelectronic defect characterization. However, re-deposition (contamination), ion implantation/damage especially for desirable thinner sections (<∼50 nm) remain major concerns for further applications.While much of the excitement in TEM community for FIB is due to thin foil specimen preparation (especially in microelectronics), we have been exploiting the site-specific micromachining aspect of FIB beyond specimen preparation for TEM, which is the focus of this contribution. Two broad themes will be presented: One exploits the site-specificity of FIB in making thin sections (including lift-off) at and across localized deformation as in indentation response of micro/nanocomposites. The other involves FIB as a fabrication tool for sputtering/drilling arbitrary shapes and sizes down to 20-50 nm, to enhance functional aspects.