Wavelength-dispersive X-ray (WDX) spectroscopy was used to measure silicon atom concentrations in the range 35–100 ppm [corresponding to (3–9) × 1018 cm−3] in doped AlxGa1–xN films using an electron probe microanalyser also equipped with a cathodoluminescence (CL) spectrometer. Doping with Si is the usual way to produce the n-type conducting layers that are critical in GaN- and AlxGa1–xN-based devices such as LEDs and laser diodes. Previously, we have shown excellent agreement for Mg dopant concentrations in p-GaN measured by WDX with values from the more widely used technique of secondary ion mass spectrometry (SIMS). However, a discrepancy between these methods has been reported when quantifying the n-type dopant, silicon. We identify the cause of discrepancy as inherent sample contamination and propose a way to correct this using a calibration relation. This new approach, using a method combining data derived from SIMS measurements on both GaN and AlxGa1–xN samples, provides the means to measure the Si content in these samples with account taken of variations in the ZAF corrections. This method presents a cost-effective and time-saving way to measure the Si doping and can also benefit from simultaneously measuring other signals, such as CL and electron channeling contrast imaging.

For a long time, secondary ion mass spectrometry (SIMS) was the only technique allowing impurity concentrations below 1 at% to be precisely measured in a sample with a depth resolution of few nanometers. For example, SIMS is the classical technique used in microelectronics to study dopant distribution in semiconductors and became, after radiotracers were forsaken, the principal tool used for atomic transport characterization (diffusion coefficient measurements). Due to the lack of other equivalent techniques, sometimes SIMS could be used erroneously, especially when the analyzed solute atoms formed clusters, or for interfacial concentration measurements (segregation coefficient measurements) for example. Today, concentration profiles measured by atom probe tomography (APT) can be compared to SIMS profiles and allow the accuracy of SIMS measurements to be better evaluated. However, APT measurements can also carry artifacts and limitations that can be investigated by SIMS. After a summary of SIMS and APT measurement advantages and disadvantages, the complementarity of these two techniques is discussed, particularly in the case of experiments aiming to measure diffusion and segregation coefficients.

A multidisciplinary approach has been used to study Au occurrences within pyrite and arsenopyrite in four refractory Au ores from Colombia, France (Le Châtelet and Villeranges) and Portugal (Neves Norte). The Au was characterized by optical and scanning electron microscopy and analysed using electron and ion microprobes to determine Au distribution, with particular attention to spectral interferences in electron and ion microprobes, background measurements in electron probes, and quantitative analysis using external standardization in ion probes. The ionic emission rate is proven to be dependent on the Au status; combined Au has a greater ion emission than metallic Au. Invisible Au occurrences are closely linked to As distribution. Gold bonding in arsenopyrite, examined by transmission electron microscopy, is shown to be dispersed within the FeAsS crystal structure. Typical growth patterns and As-Au diffusion zoning in pyrite and arsenopyrite may account for the very irregular distribution of Au in these minerals.

Owing to the development of new ion source technology, users of focused ion beams (FIBs) have access to superior performance when compared with the industry standard Ga+ liquid metal ion source. FIBs equipped with an inductively coupled plasma (ICP) ion source are better able to carry out large volume milling applications by providing up to 2 µA of Xe+ ions focused into a sub-5 µm spot. However, ICP FIBs are presently limited to 25 nm imaging resolution at 1 pA.The gas field ionization source (GFIS) relies upon an ion source that is the size of a single atom and correspondingly gains high brightness through its very small source size. The high brightness allows the GFIS to produce a very small focused probe size (<0.35 nm for helium), but with comparatively small beam currents (less than 2 pA). The Cs+ low temperature ion source, still being developed, has a projected sub-nm focal spot size at 1 pA, a maximum current of several nanoamps, and has the potential to offer integrated secondary ion mass spectrometry capabilities.

Laser surface melting is one of the most important processes in laser material processing. Selective vaporization of alloying elements in laser melting offers fundamental understanding of laser processing on metallic alloys. This work provides linkage between laser melting and material properties using secondary ion mass spectrometry (SIMS) for tiny vaporized species in laser-generated plume and energy dispersive spectroscopy (EDS) for solid solution range in molten pool, both qualitatively and quantitatively (up to hundreds of micron). Silicon wafer was used to collect the generated plume. Chemical analysis was carried out on top surface and sub-surface of the deposited plume. Transport behavior as well as distribution of the vaporized species inside the plume was further proposed.

Environmental sampling (ES) is a powerful technique used by safeguards inspectors of the International Atomic Energy Agency and the European Safeguards Office for the detection of undeclared nuclear activities. Since its implementation in the 1990s, ES has proven to be very sensitive and effective. Considering the consequences, the measurements should be carried out under a quality management programme. At the Institute for Reference Materials and Measurements, a new production method is under development for the preparation of reference uranium particles from well-certified UF6, allowing uranium particles with certified isotopic abundances to be prepared that are representative of those found in uranium enrichment facilities. Using an aerosol deposition chamber designed and built for the purpose, particles are formed by the hydrolysis of UF6 and their morphology and (isotopic) composition measured using SEM-EDX and SIMS. The SEM measurements show that by varying the relative humidity of the air in the reaction chamber, the morphology of the particles can be changed. By making a distribution map of the chemical composition of the particles, the relationship between fluorine and uranium as main constituents of the particle could be established. The presence of fluorine is a valuable indicator for the occurrence of nondeclared enrichment activities.

Imaging techniques often suffer from distortion effects. Former methods of reducing these distortions have been based either on improving the imaging technique (i.e., to avoid distortions) or on the use of reference samples (i.e., to determine the distortion field by imaging of a known structure. We present a novel method of correcting image distortion by evaluating the imaged position changes due to two small sample position shifts. The algorithm allows us to calculate a vector field, which enables us to determine the “undistorted” position of any point of the image. The presented method has very low presuppositions about the sample, requires no reference samples, and is applicable to any type of image distortion. In addition to the presentation of the method's theoretical basis and a description of the computational method, we present corrected secondary ion mass spectroscopy (SIMS) images of a regular structure (a copper grid) as well as a stochastic distribution (sodium impurities) to show the results of empirical data.

This article will discuss the importance of Raimond Castaing’s thesis on the genesis of a nondestructive and truly quantitative microanalytical method that assisted the scientific community in moving forward in the development of microanalytical instruments. I will also share with you my recollection of the decades of improvement in the electron probe microanalyzer (EPMA), that has allowed us to reach our present level of instrument sophistication, and I will explore with you my thoughts on the future evolution of this technique. To conclude, I will present the current status of related microanalysis techniques developed under Castaing in Orsay in the 1960s, as Castaing’s interest in microanalysis was not limited to electron probe microanalysis alone.