The technique of atom probe tomography (APT) is reviewed with an emphasis on illustrating what is possible with the technique both now and in the future. APT delivers the highest spatial resolution (sub-0.3-nm) three-dimensional compositional information of any microscopy technique. Recently, APT has changed dramatically with new hardware configurations that greatly simplify the technique and improve the rate of data acquisition. In addition, new methods have been developed to fabricate suitable specimens from new classes of materials. Applications of APT have expanded from structural metals and alloys to thin multilayer films on planar substrates, dielectric films, semiconducting structures and devices, and ceramic materials. This trend toward a broader range of materials and applications is likely to continue.

Invited review article: Atom probe tomography.

Vascular stenosis triggers adaptive cellular responses that induce adverse remodeling, which can progress to partial or complete vessel occlusion. Despite its severity, cellular interactions and biophysical cues that regulate pathological progression are poorly understood. We report the design and fabrication of a three-dimensional in vitro system to model vascular stenosis so that specific cellular interactions and responses to hemodynamic stimuli can be investigated. Tubular cellularized constructs (cytotubes) were produced using a collagen casting system to generate a stenotic arterial model. Fabrication methods were developed to create cytotubes containing co-cultured vascular cells, where cell viability, distribution, morphology, and contraction were examined (Figure). Fibroblasts, bone marrow primary cells, smooth muscle cells (SMCs), and endothelial cells (ECs) remained viable during culture and developed locationand time-dependent morphologies. We found cytotube contraction to depend on cellular composition, where SMC-EC co-cultures adopted intermediate contractile phenotypes between SMCand EC-only cytotubes. Our fabrication approach and resulting artery model can serve as an in vitro 3D culture system to investigate vascular pathogenesis.

Microscopy and Microanalysis

In the world of tomographic imaging, atom probe tomography (APT) occupies the high-spatial-resolution end of the spectrum. It is highly complementary to electron tomography and is applicable to a wide range of materials. The current state of APT is reviewed. Emphasis is placed on applications and data analysis as they apply to many fields of research and development including metals, semiconductors, ceramics, and organic materials. We also provide a brief review of the history and the instrumentation associated with APT and an assessment of the existing challenges in the field.

Atom Probe Tomography 2012

Atom-probe field-ion microscopy

The development of three-dimensional (3-D), characterisation techniques with high spatial and mass resolution is crucial for understanding and developing advanced materials for many engineering applications as well as for understanding natural materials. In recent decades, atom probe tomography (APT), which combines a point projection microscope and time-of-flight mass spectrometer, has evolved to be an excellent characterisation technique capable of providing 3-D nanoscale characterisation of materials with sub-nanometer scale spatial resolution, with equal sensitivity for all elements. This review discusses the current state, as of APT instrumentation, new developments in sample preparation methods, experimental procedures for different material classes, reconstruction of APT results, the current status of correlative microscopy, and application of APT for microstructural characterisation in established scientific areas like structural materials as well as new applications in semiconducting nano...

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Three-dimensional nanoscale characterisation of materials by atom probe tomography

Atom probe tomography and scanning transmission electron microscopy has been used to analyze a commercial microelectronics device prepared by depackaging and focused ion beam milling. Chemical and morphological data are presented from the source, drain and channel regions, and part of the gate oxide region of an Intel® i5-650 p-FET device demonstrating feasibility in using these techniques to investigate commercial chips.

Toward atom probe tomography of microelectronic devices

Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois, USA, July 30 – August 3, 2006

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Instrumentation Developments in Atom Probe Tomography: Applications in Semiconductor Research

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Optimized Laser Thermal Pulsing of Atom Probe Tomography: LEAP 4000X™

Over the past 15 years, the number of peer reviewed publications referencing the use of atom probe tomography (APT) has grown by nearly a factor of five [1]. A number of factors are involved in this very rapid adoption of APT, a microscopy that has been in use since the early 1970s. The performance of the typical atom probe today is orders of magnitude better than the early systems in terms of data collection rate, field of view, mass resolving power, reliability and software. The availability of easy to use laser pulsed systems coupled with the changes in performance and availability of FIB-SEM sample preparation has dramatically opened the array of applications that can be analyzed. These advances, with the improved ease of use and availability of atom probe tomography microscopes, have changed the typical user from an expert in APT to a scientist looking for answers that other microscopies cannot provide.

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Hardware and Software Advances in Commercially Available Atom Probe Tomography Systems

The standard reconstruction model with the IVAS ® software suite has historically relied on a spherical apex model [1]. The assumption of simple projection properties causes well-known issues when trying to reconstruct data from some specimens with structures of different evaporation fields [2] We are introducing a set of tools to facilitate reconstruction of atom probe tomography data to non-spherical apex forms, incorporating the resulting electrostatics.

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D Lenz

Papers

Toward atom probe tomography of microelectronic devices

Instrumentation Developments in Atom Probe Tomography: Applications in Semiconductor Research

Optimized Laser Thermal Pulsing of Atom Probe Tomography: LEAP 4000X™

Hardware and Software Advances in Commercially Available Atom Probe Tomography Systems

A System for Electrostatic Reconstructions