Focused ion beam

About: Focused ion beam is a research topic. Over the lifetime, 12154 publications have been published within this topic receiving 179523 citations. The topic is also known as: FIB.

Oxygen Transport Kinetics of Mixed Ionic-Electronic Conductors by Coupling Focused Ion Beam Tomography and Electrochemical Impedance Spectroscopy

Abstract: The oxygen reduction reaction of mixed ionic-electronic conducting (MIEC) cathodes Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) and La0.58Sr0.4Co0.2Fe0.8O3-δ (LSCF) is investigated by detailed electrochemical impedance spectroscopy and focused ion beam tomography. The oxygen transport parameters of these materials are usually determined for model systems, such as dense bulks or thin films. However in the present study, probable differences regarding the time and thermal history of the samples (e.g. ambient poisoning gases, grain coarsening, secondary phase or surface segregation, etc.) were avoided by the in situ sintering of electrodes with nominal stoichiometry under synthetic air. The microstructural parameters of the electrodes are obtained by 3D FIB-SEM reconstruction tomography and subsequently used in combination with the Adler-Lane-Steele analytical model to calculate a simulated cathode resistance. Large discrepancies are observed compared to the electrochemical impedance measurements. In particular, the electrochemical impedance measurements do not show a Gerischer behavior, as expected for MIEC materials controlled by a coupled surface-exchange and bulk diffusion. Analysis by distribution function of relaxation times (DRT) reveals four individual processes taking place, indicating a surface-exchange controlled behavior with a reaction zone similar to the particle size. Bulk diffusion (D) and surface-exchange (k) coefficients from literature are critically discussed and tentative surface-exchange coefficients (k) for both MIECs are given.

Reactive Ion Beam Etching with CF 4: Characterization of a Kaufman Ion Source and Details of SiO2 Etching

Abstract: Recently, the use of reactive gases in ion milling equipment has received increasing attention. We have characterized the operation of a Kaufman‐type ion source for use with , by mass spectrometric measurements of both ionic and neutral components of the beam. Fragmentation of the parent gas to ions and neutrals is found to be extensive. Fragmentation is also strongly dependent on gas pressure and on confinement of the discharge in the source due to the axial magnetic field. Previously reported dependence of etch rate on background gas pressure is examined in more detail. It is concluded that variation of ion composition does effect etch rate, but ion‐induced reaction of adsorbed neutral species is occurring. A simple mass transport model that considers adsorption and desorption processes of reagent and product species is adequate to explain the major features of the data.

Microstructure and lubrication mechanism of multilayered MoS2/Sb2O3 thin films

Abstract: Multilayered MoS2/Sb2O3 thin films were prepared by pulsed laser deposition on steel substrates. A rotary multi-target holder was used to switch the laser targets for alternative growth of MoS2 and Sb2O3 layers providing nanometers thickness. The tribological properties of the films were measured in dry and wet environments and the wear scars were observed using a scanning electron microscope. The multilayer films showed a much longer wear life than pure MoS2 films in wet air tribotests. Focused ion beam and transmission electron microscopies were used to investigate the cross-sectional microstructures of wear scars. Lubricious MoS2/Sb2O3 tribofilms were built up on wear scar surfaces, and produced low friction. Micro-cracks occurred along the interface between the tribofilm and the neighboring/topmost Sb2O3 underlayer, where the Sb2O3 layer effectively inhibited the crack propagation perpendicular to the interface. The orientation of MoS2 crystals in as-deposited films was mostly random and friction-induced stress oriented the MoS2 basal planes parallel to the surface. The reorientation was confined to the topmost MoS2 layer and was not observed below the first intact Sb2O3 layer.

Recent Advances in Vacuum Arc Ion Sources

Abstract: Intense beams of metal ions can be formed from a vacuum arc ion source. This kind of source works well for most of the solid metals of the Periodic Table, and because the ions are, in general, multiply stripped with charge states as high as 4+ to 6+ , the mean energy of the ion beam produced can be 100–200 keV for an extractor voltage in the comfortable range of about 50–75 kV. Broad-beam extraction is convenient, and the time-averaged ion beam current delivered downstream can readily be in the tens of milliamperes range. The vacuum arc ion source has, for these reasons, found good application for metallurgical surface modification: it provides relatively simple and inexpensive access to high dose metal ion implantation. Several important source developments have been demonstrated recently, including very-broad-beam operation, macroparticle removal, charge state enhancement and the formation of gaseous beams. We have made a very-broad-beam source embodiment with beam formation electrodes 50 cm in diameter (area, 2000 cm 2 ), producing a beam with a width of approximately 35 cm for a nominal beam area of about 1000 cm 2 , and a pulsed Ti beam current of about 7 A was formed at a mean ion energy of approximately 100 keV. Separately, we have developed a high efficiency macroparticle-removing magnetic filter and have incorporated such a filter into a vacuum arc ion source so as to form macroparticle-free ion beams. Jointly with researchers at the High Current Electronics Institute, Tomsk, Russia and the Gesellschaft fur Schwerionenforschung, Darmstadt, Germany, we have developed a compact technique for increasing the charge states of ions produced in the vacuum arc plasma, thus providing a simple means of increasing the ion energy at fixed extractor voltage. Finally, operation with mixed metal and gaseous ion species has been demonstrated. In this paper, we briefly review the operation of vacuum arc ion sources and the typical beam and implantation parameters that can be obtained, and describe these source advances and their bearing on metal ion implantation applications.