A review of focused ion beam milling techniques for TEM specimen preparation
TL;DR: The use of focused ion beam (FIB) milling for the preparation of transmission electron microscopy (TEM) specimens is described in this article, where the operation of the FIB instrument is discussed and the conventional and lift-out techniques for TEM specimen preparation and the advantages and disadvantages of each technique are detailed.
About: This article is published in Micron.The article was published on 1999-06-01. It has received 1078 citations till now. The article focuses on the topics: Conventional transmission electron microscope & Energy filtered transmission electron microscopy.
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TL;DR: In this paper, a cross sectional TEM view of several graphene and boron nitride heterostructures is presented, showing that the trapped hydrocarbons segregate into isolated pockets, leaving the interfaces atomically clean.
Abstract: Heterostructures of very thin films have been used for decades in research and industry. Now a transmission electron microscopy study demonstrates the possibility of realizing perfect structures built by piling up one-atom-thick layers of graphene and boron nitride. By stacking various two-dimensional (2D) atomic crystals1 on top of each other, it is possible to create multilayer heterostructures and devices with designed electronic properties2,3,4,5. However, various adsorbates become trapped between layers during their assembly, and this not only affects the resulting quality but also prevents the formation of a true artificial layered crystal upheld by van der Waals interaction, creating instead a laminate glued together by contamination. Transmission electron microscopy (TEM) has shown that graphene and boron nitride monolayers, the two best characterized 2D crystals, are densely covered with hydrocarbons (even after thermal annealing in high vacuum) and exhibit only small clean patches suitable for atomic resolution imaging6,7,8,9,10. This observation seems detrimental for any realistic prospect of creating van der Waals materials and heterostructures with atomically sharp interfaces. Here we employ cross sectional TEM to take a side view of several graphene–boron nitride heterostructures. We find that the trapped hydrocarbons segregate into isolated pockets, leaving the interfaces atomically clean. Moreover, we observe a clear correlation between interface roughness and the electronic quality of encapsulated graphene. This work proves the concept of heterostructures assembled with atomic layer precision and provides their first TEM images.
827 citations
TL;DR: In this paper, an overview of the variety of techniques that have been developed to prepare the final transmission electron microscope (TEM) specimen is presented, as well as the problems such as FIB-induced damage and Ga contamination.
Abstract: One of the most important applications of a focused ion beam (FIB) workstation is preparing samples for transmission electron microscope (TEM) investigation. Samples must be uniformly thin to enable the analyzing beam of electrons to penetrate. The FIB enables not only the preparation of large, uniformly thick, sitespecific samples, but also the fabrication of lamellae used for TEM samples from composite samples consisting of inorganic and organic materials with very different properties. This article gives an overview of the variety of techniques that have been developed to prepare the final TEM specimen. The strengths of these methods as well as the problems, such as FIB-induced damage and Ga contamination, are illustrated with examples. Most recently, FIB-thinned lamellae were used to improve the spatial resolution of electron backscatter diffraction and energy-dispersive x-ray mapping. Examples are presented to illustrate the capabilities, difficulties, and future potential of FIB.
791 citations
TL;DR: In this paper, the authors describe the way in which strongly modulated photonic crystals differ from other optical media, and clarify what they can do, including light confinement, frequency dispersion and spatial dispersion.
Abstract: Recently, strongly modulated photonic crystals, fabricated by the state-of-the-art semiconductor nanofabrication process, have realized various novel optical properties. This paper describes the way in which they differ from other optical media, and clarifies what they can do. In particular, three important issues are considered: light confinement, frequency dispersion and spatial dispersion. First, I describe the latest status and impact of ultra-strong light confinement in a wavelength-cubic volume achieved in photonic crystals. Second, the extreme reduction in the speed of light is reported, which was achieved as a result of frequency dispersion management. Third, strange negative refraction in photonic crystals is introduced, which results from their unique spatial dispersion, and it is clarified how this leads to perfect imaging. The last two sections are devoted to applications of these novel properties. First, I report the fact that strong light confinement and huge light–matter interaction enhancement make strongly modulated photonic crystals promising for on-chip all-optical processing, and present several examples including all-optical switches/memories and optical logics. As a second application, it is shown that the strong light confinement and slow light in strongly modulated photonic crystals enable the adiabatic tuning of light, which leads to various novel ways of controlling light, such as adiabatic frequency conversion, efficient optomechanics systems, photon memories and photons pinning.
403 citations
20 Aug 2008-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the authors investigated the uniaxial compression behavior of focused ion beam (FIB) manufactured [1 1 1/1] nickel (Ni) small-scale pillars, ranging in diameter from approximately 25μm to below 200nm, in order to examine the effect of crystallographic orientation on the mechanical properties.
Abstract: This study investigates uniaxial compression behavior of focused ion beam (FIB) manufactured [1 1 1] nickel (Ni) small-scale pillars, ranging in diameter from approximately 25 μm to below 200 nm, in order to examine the effect of crystallographic orientation on the mechanical properties. This study is unique from other micro-pillar studies in that the [1 1 1] orientation has a considerably lower Schmid factor, and has multiple slip systems available. The [1 1 1] Ni pillars show a strong increase in yield stress and work hardening with decreasing diameter. The relationship between yield stress and diameter (σy ∝ d−0.69) matches well with previous small-scale pillar studies. Strain hardening, which has been inconsistently observed in other micro-pillar studies, is found to be a function of both diameter and orientation. Although the precise mechanism for hardening is unknown, transmission electron microscopy reveals dislocations throughout the pillar and into the base material suggesting that dislocation interactions and deformation below the pillar play a role in the observed strain hardening. Furthermore, a slight crystallographic rotation of the pillar is observed likely contributing to the observed mechanical properties. By exploring the role of crystallography on the plastic deformation behavior, this study provides additional insight into the nature of the size effect.
362 citations
TL;DR: Several FIB-based methods that have been developed to fabricate needle-shaped atom probe specimens from a variety of specimen geometries, and site-specific regions are reviewed, which have enabled electronic device structures to be characterized.
Abstract: Several FIB-based methods that have been developed to fabricate needle-shaped atom probe specimens from a variety of specimen geometries, and site-specific regions are reviewed. These methods have enabled electronic device structures to be characterized. The atom probe may be used to quantify the level and range of gallium implantation and has demonstrated that the use of low accelerating voltages during the final stages of milling can dramatically reduce the extent of gallium implantation.
349 citations
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TL;DR: A novel scheme is presented for the preparation of cross‐section transmission electron microscopy (TEM) specimens, with a focused ion beam (FIB), particularly suitable for highly structured substrates, such as integrated circuits.
Abstract: A novel scheme is presented for the preparation of cross‐section transmission electron microscopy (TEM) specimens, with a focused ion beam (FIB). This scheme is particularly suitable for highly structured substrates, such as integrated circuits. The specimen is made by cutting a thin slice of material from the substrate by sputtering with the FIB. The position of the specimen can be selected with submicron resolution. The specimen is subsequently removed from the substrate and transported to a standard TEM‐specimen holder. A specimen, ready for TEM inspection, can be prepared within 2 hs. The samples are of excellent quality as is illustrated with cross‐section TEM images of FIB‐made specimens of an electrically programmable read‐only memory.
248 citations
TL;DR: A site specific technique for cross-section transmission electron microscopy specimen preparation of difficult materials is presented in this paper, where focused ion beams are used to slice an electron transparent sliver of the specimen from a specific area of interest.
Abstract: A site specific technique for cross-section transmission electron microscopy specimen preparation of difficult materials is presented. Focused ion beams are used to slice an electron transparent sliver of the specimen from a specific area of interest. Micromanipulation lift-out procedures are then used to transport the electron transparent specimen to a carbon coated copper grid for subsequent TEM analysis. The experimental procedures are described in detail and an example of the lift-out technique is presented.
165 citations
TL;DR: In this article, the FIB lift-out method was used to produce a site-specific TEM specimen from a difficult material in under 3 hours. But the results of the TEM analysis revealed a large amount of thin area free from characteristic signs of damage that may be observed as a result of conventional argon ion milling.
Abstract: Particles of Zn powder have been studied to show that high-quality scanning electron microscope (SEM) and transmission electron microscope (TEM) specimens can be rapidly produced from a site-specific region on a chosen particle by the focused ion beam (FIB) lift-out technique. A TEM specimen approximately 20-µm long by 5-µm wide was milled to electron transparency, extracted from the bulk particle, and micromanipulated onto a carbon coated copper mesh TEM grid. Using the FIB lift-out method, we were able to prepare a site-specific TEM specimen from a difficult material in under 3 hours. The TEM analysis of the lift-out specimen revealed a large amount of thin area free from characteristic signs of damage that may be observed as a result of conventional argon ion milling. The overall microstructure of the specimen prepared by the FIB lift-out method was consistent with samples prepared by conventional metallographic methods. A grain size of ∼10 to 20 µm was observed in all specimens by both TEM and SEM analysis. Light optical microscopy revealed the presence of internal voids in ∼10 to 20 pct of all particles. The SEM analysis showed the voids to extend over ∼70 pct of the particle volume in some cases.
75 citations
TL;DR: Focused ion beam (FIB) systems using gallium liquid metal ion sources can remove material with a lateral resolution below 50 nm and can produce metal deposition at a similar resolution with ion beam-enhanced chemical vapour deposition as mentioned in this paper.
Abstract: Focused ion beam (FIB) systems using gallium liquid metal ion sources can remove material with a lateral resolution below 50 nm and can produce metal deposition at a similar resolution with ion beam-enhanced chemical vapour deposition. These capabilities have resulted in many valuable applications for the microelectronics industry. Circuit modifications are possible because existing connections can be severed and reconnected to different locations. Testing of circuitry can be enhanced by isolation of specific circuits, removal of overlayers and by creation of probe pads where desired. Grain sizes can be determined from secondary electron images by the delineation of individual grains due to orientation-dependent channeling of the ion beam. Secondary ion mass spectrometry analyses of small areas can provide ion images, elemental identification of small areas and endpoint detection with depth profiles. Scanning electron microscopy and transmission electron microscopy sections are prepared routinely using the FIB. These FIB-prepared sections are notable because specific features, such as defects, can be exposed and a range of materials including silicon, indium phosphide, gallium arsenide and even metal layers can be cut without distortion. Transmission electron micrographs of superior quality have been obtained with a large area of very uniform thickness that permits identification of features such as areas under stress.
67 citations