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.

Patterning Metallic Nanostructures by Ion-Beam-Induced Dewetting and Rayleigh Instability

Abstract: Alternative fabrication and patterning of ordered nanostructures has become critically important as the size of devices reaches the nanoscale and the resolution of conventional optical lithography approaches its physical limit. Here, we have developed a simple method that allows one to pattern metallic surface nanostructures with precisely controlled size, spacing, and location using ion-beam-induced dewetting and Rayleigh instability. Predefined patterns by focused ion beam direct-writing were used as the templates for the self-organization of ordered nanostructures. Single or double chains, concentric rings, and two-dimensional arrays of metallic nanoparticles with a well-controlled spacing, diameter, and location were fabricated. This approach represents a maskless process that combines the top-down and bottom-up patterning methods, and no chemical etching or pattern transfer steps are involved. This method can be applied to many metallic systems in constructing complex, higher-order functional nanostr...

Focused-ion-beam-induced deposition of superconducting nanowires

Abstract: Superconducting nanowires, with a critical temperature of 5.2K, have been synthesized using an ion-beam-induced deposition, with a gallium focused ion beam and tungsten carboxyl, W(CO)6, as precursor. The films are amorphous, with atomic concentrations of about 40%, 40%, and 20% for W, C, and Ga, respectively, 0K values of the upper critical field and coherence length of 9.5T and 5.9nm, respectively, are deduced from the resistivity data at different applied magnetic fields. The critical current density is Jc=1.5×105A∕cm2 at 3K. This technique can be used as a template-free fabrication method for superconducting devices.

Imaging three-dimensional tissue architectures by focused ion beam scanning electron microscopy

Abstract: In this protocol, we describe a 3D imaging technique known as 'volume electron microscopy' or 'focused ion beam scanning electron microscopy (FIB/SEM)' applied to biological tissues. A scanning electron microscope equipped with a focused gallium ion beam, used to sequentially mill away the sample surface, and a backscattered electron (BSE) detector, used to image the milled surfaces, generates a large series of images that can be combined into a 3D rendered image of stained and embedded biological tissue. Structural information over volumes of tens of thousands of cubic micrometers is possible, revealing complex microanatomy with subcellular resolution. Methods are presented for tissue processing, for the enhancement of contrast with osmium tetroxide/potassium ferricyanide, for BSE imaging, for the preparation and platinum deposition over a selected site in the embedded tissue block, and for sequential data collection with ion beam milling; all this takes ~90 h. The imaging conditions, procedures for alternate milling and data acquisition and techniques for processing and partitioning the 3D data set are also described; these processes take ~30 h. The protocol is illustrated by application to developing chick cornea, in which cells organize collagen fibril bundles into complex, multilamellar structures essential for transparency in the mature connective tissue matrix. The techniques described could have wide application in a range of fields, including pathology, developmental biology, microstructural anatomy and regenerative medicine.

Minimizing damage during FIB sample preparation of soft materials

Abstract: Summary Although focused ion beam (FIB) microscopy has been used successfully for milling patterns and creating ultra-thin electron and soft X-ray transparent sections of polymers and other soft materials, little has been documented regarding FIB-induced damage of these materials beyond qualitative evaluations of microstructure. In this study, we sought to identify steps in the FIB preparation process that can cause changes in chemical composition and bonding in soft materials. The impact of various parameters in the FIB-scanning electron microscope (SEM) sample preparation process, such as final milling voltage, temperature, ion beam overlap and mechanical stability of soft samples, was evaluated using two test-case materials systems: polyacrylamide, a low melting-point polymer, and Wyodak lignite coal, a refractory organic material. We evaluated changes in carbon bonding in the samples using X-ray absorption near-edge structure spectroscopy (XANES) at the carbon K edge and compared these samples with thin sections that had been prepared mechanically using ultramicrotomy. Minor chemical changes were induced in the coal samples during FIB-SEM preparation, and little effect was observed by changing ion-beam parameters. However, polyacrylamide was particularly sensitive to irradiation by the electron beam, which drastically altered the chemistry of the sample, with the primary damage occurring as an increase in the amount of aromatic carbon bonding (C=C). Changes in temperature, final milling voltage and beam overlap led to small improvements in the quality of the specimens. We outline a series of best practices for preparing electron and soft X-ray transparent samples, with respect to preserving chemical structure and mechanical stability of soft materials using the FIB.