Specifications for Hard Condensed Matter Specimens for Three-Dimensional High-Resolution Tomographies

Abstract

Tomography is a standard and invaluable technique that covers a large range of length scales. It gives access to the inner morphology of specimens and to the three-dimensional (3D) distribution of physical quantities such as elemental composition, crystalline phases, oxidation state, or strain. These data are necessary to determine the effective properties of investigated heterogeneous media. However, each tomographic technique relies on severe sampling conditions and physical principles that require the sample to be adequately shaped. For that purpose, a wide range of sample preparation techniques is used, including mechanical machining, polishing, sawing, ion milling, or chemical techniques. Here, we focus on the basics of tomography that justify such advanced sample preparation, before reviewing and illustrating the main techniques. Performances and limits are highlighted, and we identify the best preparation technique for a particular tomographic scale and application. The targeted tomography techniques include hard X-ray micro- and nanotomography, electron nanotomography, and atom probe tomography. The article mainly focuses on hard condensed matter, including porous materials, alloys, and microelectronics applications, but also includes, to a lesser extent, biological considerations.

3D correlative morphological and elemental characterization of materials at the deep submicrometre scale

“…Moreover, relatively large samples (up to hundreds of micrometres) can be precisely shaped due to the wide range of available currents (from 1.5 pA to 1.3 A). In order to obtain a cylindrical sample, the lift‐out technique (Bleuet et al ., ) has been used. Initially, a ring pattern with the external diameter of 165 m, the internal diameter of 60 m and the depth of around 85 m has been milled in the plate perpendicularly to its surface.…”

Nanoscale voxel spectroscopy by simultaneous EELS and EDS tomography

“…[33][34][35][36][37] Nevertheless the modification and refinement mechanisms are still a matter of debate and require understanding of the elemental distribution down to the atomic level. 35 A needle shaped sample, suitable for tomography, was prepared from the surface of the Al-Si sample using focused ion beam (FIB) milling 38,39 (see ESI †).…”

Doping porous silicon with erbium: pores filling as a method to limit the Er-clustering effects and increasing its light emission

“…Needle-ET needs a needle-shaped sample with a diameter of a few hundred nanometers. Needle-shaped samples are prepared using a Focus Ion Beam (FIB) FEI Strata instrument 75 . After depositing protective layers (Tetraethyl orthosilicate (TEOS) followed by W) on the surface of the specimen, a chunk containing the PSi thin film is extracted.…”