Focused Ion Beam (FIB): A novel technology for advanced application of micro- and nanoanalysis in geosciences and applied mineralogy

Abstract

The Focused Ion Beam (FIB) tool has been successfully used as both a means to prepare site-specific TEM foils for subsequent analysis by TEM, as well as a stand-alone instrument for micromachining of materials. TEM foil preparation with FIB technique has drastically changed traditional TEM specimen preparation because it allows site-specific foil preparation. FIB consists of cutting electron transparent foils through Ga-ion milling on a bulk sample. Optical microscopy together with a micromanipulator is used to transfer the foil from the specimen to a TEM grid coated with a holey carbon support film. No further carbon coating is required. This novel technology offers significant benefits in precision and speed of preparing site-specific TEM foils from inclusions in minerals, grain boundaries, microfossils, thin films on substrates and various coatings. FIB cut TEM foils can be investigated with modern TEM techniques such as various diffraction techniques, analytical electron microscopy (AEM) including line scan and elemental mapping, electron energy-loss spectroscopy (EELS) and high-resolution electron microscopy (HREM). With the FIB instrument (FEI FIB200) operated since fall 2002 at GFZ Potsdam we have prepared and investigated several hundreds of high quality TEM foils from silicates, carbonates, metals alloys, ceramic materials and diamond.

Nb–Ta–(Ti–Sn) oxide mineral chemistry as tracer of rare-element granitic pegmatite fractionation in the Borborema Province, Northeastern Brazil

“…In some cassiterite ('pseudostaringite') crystals, a primary compositional zoning was also preserved, now defined by variations in frequency and type of fine (micrometer sized) to ultrafine sub-microscopic (0.1 μm or less) exsolutions, with lamellar columbite exsolutions in the core (thus Nbsaturated cassiterite host) and emulsion-like ferrowodginite exsolutions at the rim (thus Ta-saturated, Beurlen et al 2004). It is remarkable that in other samples of the border zone of the same pegmatite, a reverse trend is observed in idiomorphic crystals with ferrotantalite cores, enveloped by a Ti-Nb-rich rim of ixiolite (electron diffraction analyses in a high resolution transmission electron microscope confirmed the phase determination, using the FIB sampling method described by Wirth (2004)). …”

Faulting processes in active faults – Evidences from TCDP and SAFOD drill core samples

“…Microstructures were investigated with a petrographic microscope, a FEI Quanta 3D scanning electron microscope (SEM) combined with focused ion beam (FIB, dual-beam machine), and a FEI Tecnai G2 F20 X-Twin transmission electron microscope (TEM/AEM) equipped with a Gatan Tridiem energy filter, a Fishione high-angle annular dark field detector (HAADF), and an energy dispersive Xray analyzer (EDS) to determine chemical composition. The samples for TEM studies were prepared with a focused ion beam (FIB) device (FEI FIB200TEM) at GeoForschungsZentrum (GFZ) (for more details see Wirth, 2004Wirth, , 2009. The cutting of foils with the FIB allows identification of microstructures down to the nm scale while minimizing preparation induced damage.…”

Validity of the Apatite/Merrillite Relationship in Evaluating the Water Content in the Martian Mantle: Implications from Shergottite Northwest Africa (NWA) 2975

“…No carbon coating was applied to prevent charging under the electron beam. Details regarding the TEM sample preparation are provided elsewhere [46,47]. TEM was performed using a FEI Tecnai F20 X-Twin TEM (Thermo Fisher, Hillsboro, Oregon, USA) with a Schottky field emitter as an electron source.…”