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.

Highly ordered Ga nanodroplets on a GaAs surface formed by a focused ion beam.

Abstract: The morphological evolution of a GaAs surface induced by a focused ion beam (FIB) has been investigated by in situ electron microscopy. Under off-normal bombardment without sample rotation, Ga droplets with sizes from 70 to 25 nm in diameter on the GaAs surface can self-assemble into a highly ordered hexagonal pattern instead of Ostwald ripening or coalescence. The mechanism relies on a balance between anisotropic loss of atoms on the surface of droplets due to sputtering and an anisotropic supply of atoms on the substrate surface due to preferential sputtering of As. The ratio of wavelength to the droplet diameter predicted by this model is in excellent agreement with experimental observations.

Chemical and structural properties of conducting nanofilaments in TiN/HfO2-based resistive switching structures

Abstract: Structural, chemical and electronic properties of electroforming in the TiN/HfO2 system are investigated at the nanometre scale. Reversible resistive switching is achieved by biasing the metal oxide using conductive atomic force microscopy. An original method is implemented to localize and investigate the conductive region by combining focused ion beam, scanning spreading resistance microscopy and scanning transmission electron microscopy. Results clearly show the presence of a conductive filament extending over 20?nm. Its size and shape is mainly tuned by the corresponding HfO2 crystalline grain. Oxygen vacancies together with localized states in the HfO2 band gap are highlighted by electron energy loss spectroscopy. Oxygen depletion is seen mainly in the central part of the conductive filament along grain boundaries. This is associated with partial amorphization, in particular at both electrode/oxide interfaces. Our results are a direct confirmation of the filamentary conduction mechanism, showing that oxygen content modulation at the nanometre scale plays a major role in resistive switching.

Tensile deformation of electroplated copper nanopillars

Abstract: The results are presented of uniaxial tensile testing of single crystalline electroplated copper nanopillars with diameters between 75 nm and 165 nm fabricated without the use of a focused ion beam (FIB). The experiments were performed in an in situ nanomechanical instrument, SEMentor, and reveal that the pillars’ ultimate tensile strengths follow a similar power law dependence on diameter as reported for microcompression studies on fcc metals fabricated with and without FIB. Further, these pillars are characterized by limited or non-existent initial homogeneous deformation, immediately followed by necking in the top portion of the pillar. The particular deformation attributes are discussed in the context of hardening by dislocation starvation. Site-specific transmission electron microscopy microstructural analysis of as-fabricated nanopillars indicates the presence of scarce twin boundaries in some specimens. We comment on the potential for mechanical effects due to the presence of twins.

Electrochemical Deposition and Stripping Behavior of Lithium Metal across a Rigid Block Copolymer Electrolyte Membrane

Abstract: Author(s): Harry, KJ; Liao, X; Parkinson, DY; Minor, AM; Balsara, NP | Abstract: Replacing the conventional graphite anode in rechargeable batteries with lithium metal results in a significant increase in energy density. However, growth of electronically conductive structures, like dendrites, from lithium anodes causes premature battery failure by short circuit. Mechanically rigid electrolytes are thought to promote smooth lithium deposition by increasing the energy required for lithium reduction at regions of high local strain, like a dendrite tip. The study reported herein used X-ray microtomography, Focused Ion Beam (FIB) milling, and Scanning Electron Microscopy (SEM) imaging to investigate the electrochemical stripping and deposition behavior of lithium in symmetric lithium - polymer cells using a rigid polystyrene-b-poly(ethylene oxide) membrane as the electrolyte. In situ experiments show the formation of globular lithium structures that grow to puncture the polymer electrolyte membrane. They form on faceted impurity particles that are initially located at the lithium/electrolyte interface. While the impurities are uniformly distributed throughout the lithium foil in initial images, their relative concentration near the electrolyte changes as lithium is stripped from one electrode and deposited on the other. Notably, the deposited lithium is devoid of faceted impurities. This electrolytic refining of lithium could be used to prepare anodic lithium foils for batteries with improved cycle life.

Advances in helium ion microscopy

Abstract: With the advent of a reliable high brightness ion source, utilizing helium (He) as the ion species, a new branch of microscopy has emerged. The promise of sub-nm focused probe sizes coupled with the unique He beam/sample interactions has led to a range of both high resolution imaging and high fidelity material modification applications. However, realizing the full potential of the He ion source is not without its challenges. Some of the difficulties are presented, along with a discussion of a systematic effort to overcome these issues. This work has resulted in the ability to routinely take images with an edge resolution of 0.35 nm or better. The nature of the He ion beam interaction with the sample makes possible numerous diverse applications, beyond the high resolution imaging already mentioned. A few of these will be highlighted, including imaging insulating samples, scanning transmission He ion microscopy, and material modification. Finally an extension of the high source brightness technology to utilizing neon (Ne) as the ion species is described. The source properties are given, along with a calculation of the expected probe size from such a Ne ion source and column.