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.

Precise and fast secondary ion mass spectrometry depth profiling of polymer materials with large Ar cluster ion beams.

Abstract: We demonstrate depth profiling of polymer materials by using large argon (Ar) cluster ion beams. In general, depth profiling with secondary ion mass spectrometry (SIMS) presents serious problems in organic materials, because the primary keV atomic ion beams often damage them and the molecular ion yields decrease with increasing incident ion fluence. Recently, we have found reduced damage of organic materials during sputtering with large gas cluster ions, and reported on the unique secondary ion emission of organic materials. Secondary ions from the polymer films were measured with a linear type time-of-flight (TOF) technique; the films were also etched with large Ar cluster ion beams. The mean cluster size of the primary ion beams was Ar 700 and incident energy was 5.5 keV. Although the primary ion fluence exceeded the static SIMS limit, the molecular ion intensities from the polymer films remained constant, indicating that irradiation with large Ar cluster ion beams rarely leads to damage accumulation on the surface of the films, and this characteristic is excellently suitable for SIMS depth profiling of organic materials.

Counting Synapses Using FIB/SEM Microscopy: A True Revolution for Ultrastructural Volume Reconstruction.

Abstract: The advent of transmission electron microscopy (TEM) in the 1950’s represented a fundamental step in the study of neuronal circuits. The application of this technique soon led to the realization that the number of synapses changes during the course of normal life, as well as under certain pathological or experimental circumstances. Since then, one of the main goals in neurosciences has been to define simple and accurate methods to estimate the magnitude of these changes. Contrary to analysing single sections, TEM reconstructions are extremely time-consuming and difficult. Therefore, most quantitative studies use stereological methods to define the three-dimensional characteristics of synaptic junctions that are studied in two dimensions. Here, to count the exact number of synapses per unit of volume we have applied a new three-dimensional reconstruction method that involves the combination of focused ion beam milling and scanning electron microscopy (FIB/SEM). We show that the images obtained with FIB/SEM are similar to those obtained with TEM, but with the advantage that FIB/SEM permits serial reconstructions of large volumes of tissue to be generated rapidly and automatically. Furthermore, we compared the estimates of the number of synapses obtained with stereological methods with the values obtained by FIB/SEM reconstructions. We concluded that FIB/SEM not only provides the actual number of synapses per volume but it is also much easier and faster to use than other currently available TEM methods. More importantly, it also avoids most of the errors introduced by stereological methods and overcomes the difficulties associated with these techniques.

Fabrication of symmetric sub-5 nm nanopores using focused ion and electron beams

Abstract: Nanopores fabricated in solid-state membranes have previously been used for the rapid electrical detection and characterization of single biopolymer molecules. Various methods for producing solid-state nanopores have been reported, but fabricating nanopores of desired sizes controllably is still challenging. Here we report a fabrication technique which uses a focused ion beam (FIB) system to engineer nanopores precisely. This technique provides visual feedback over the formation process. The present method can produce highly symmetrical nanopores with diameters smaller than ~5?nm and can be used to create an array of multiple nanopores simultaneously. In addition, nanopores produced using the focused ion beam sculpting technique can be tailored down to less than 1?nm in diameter using high-energy electron radiation.

Three-Dimensional Reconstruction of Porous LSCF Cathodes

Abstract: Solid oxide fuel cells ! SOFCs" are efficient, environmentally friendly, and fuel-flexible electrochemical devices for the generation of electrical power and heat. 1 They consist of three basic layers: cathode, electrolyte, and anode. The cathode is a porous, conductive catalyst for the reduction of O2 and for the oxidation of fuel. Between the cathode and anode is the dense electrolyte. The circuit is completed via cathode and anode contacts to an external load. The basic chemical formula for the cathodic reduction reaction is 1 2 O2 +V o ·· +2 e! =O o x ! 1" Current SOFC performance is limited by cathode polarization, which increases with decreasing operational temperatures. 2,3 Cathode microstructure and morphology have a strong effect on this polarization. 2-4 In this initial study a dual-beam focused ion beam/scanning electron microscope ! FIB/SEM" was utilized to reconstruct an actual three-dimensional ! 3D" model of a La0.8Sr0.2Co0.2Fe0.8O3! ! ! LSCF" cathode and its interface with a dense yttrium-stabilized zirconia ! YSZ" electrolyte. This highresolution, 3D technique advances the understanding of the cathode microstructure’s effect on performance. The identification of critical microstructural properties such as surface area, tortuosity, and interfacial porosity may be correlated with the ionic, electronic, and catalytic processes for a better fundamental understanding of electrochemical performance. With this tool, SOFC material and microstructural design can be more effective in reducing cathodic polarization at lower operational temperatures. The semiconductor industry has used the FIB since the 1980s to deposit, etch, micromachine, and image specimens during different stages of circuit processing. 5,6 This technology was brought forward to reconstruct 3D, geometrically complex submicrometer structures. 7-11 With the advent of 3D modeling software, nanotomography utilizing the dual-beam FIB/SEM technique was used to quantify nanoceramic suspended powders. 10-12 This technique was applied to SOFC cermet anodes to quantify microstructural properties such as porosity, triple-phase-boundary ! TPB" length, and degree of anisotropy via tortuosity. 13 Such a technique has never before been applied to reconstruct a cathode and the cathode/ electrolyte interface.

Enhanced FIB-SEM Systems for Large-Volume 3D Imaging

Abstract: A microscopy system for imaging a sample can include a scanning electron microscope system configured for imaging a surface layer of the sample and a focused ion beam system configured for generating an ion beam for milling the surface layer away from a sample after it has been imaged. A movable mechanical shutter can be configured to be moved automatically into a position between the sample and the scanning electron microscope system, so that when the electron beam is not imaging the sample the movable mechanical shutter is positioned between the sample and the scanning electron microscope system.