We at Oxford Instruments were interested to read the article published in Microscopy and Microanalysis by Newbury (2005). Although our own views differ from those of Dr. Newbury in some respects, we do agree that this is an important matter. If this article generates an interest in the ability of a system and a user to accurately identify elements in a spectrum and encourages people to assess the quality of the qualitative analysis provided by a microanalysis system, then we believe this article has served a very useful purpose. After all, accurate element identification is the core requirement for a microanalysis system.

I am pleased to respond to the letter from Simon Burgess commenting on my article, “Misidentification of Major Constituents by Automatic Qualitative Energy Dispersive X-ray Microanalysis: A Problem That Threatens the Credibility of the Analytical Community” (Newbury, 2005). First, I am grateful for the words of support for my article, even if inevitably qualified, expressed in Mr. Burgess's letter. In response to his specific comments (in boldface), I offer the following:

A systematic distortion in high-angle annular dark-field scanning transmission electron microscope (HAADF-STEM) images, which may be caused by residual electrical interference, has been evaluated. Strain mapping, using the geometric phase methodology, has been applied to images acquired in an aberration-corrected STEM. This allows this distortion to be removed and so quantitative analysis of HAADF-STEM images was enabled. The distortion is quantified by applying this technique to structurally perfect and strain-free material. As an example, the correction is used to analyse an InAs/GaAs dot-in-quantum well heterostructure grown by molecular beam epitaxy. The result is a quantitative measure of internal strain on an atomic scale. The measured internal strain field of the heterostructure can be interpreted as being due to variations of indium concentration in the quantum dot.

Wedge polishing was used to prepare one-dimensional Si n-p junction and Si p-channel metal-oxide-silicon field effect transistor (pMOSFET) samples for precise and quantitative electrostatic potential analysis using off-axis electron holography. To avoid artifacts associated with ion milling, cloth polishing with 0.02-μm colloidal silica suspension was used for final thinning. Uniform thickness and no significant charging were observed by electron holography analysis for samples prepared entirely by this method. The effect of sample thickness was investigated and the minimum thickness for reliable results was found to be ∼160 nm. Below this thickness, measured phase changes were smaller than expected. For the pMOSFET sample, quantitative analysis of two-dimensional electrostatic potential distribution showed that the metallurgical gate length (separation between two extension junctions) was ∼54 nm, whereas the actual gate length was measured to be ∼70 nm by conventional transmission electron microscopy. Thus, source and drain junction encroachment under the gate was 16 nm.

The bulk morphology and surface features that developed upon precipitation on micrometer-size calcite powders and millimeter-size cleavage fragments were imaged by three different microscopic techniques: field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) of Pt-C replicas, and atomic force microscopy (AFM). Each technique can resolve some nanoscale surface features, but they offer different ranges of magnification and dimensional resolutions. Because sample preparation and imaging is not constrained by crystal orientation, FE-SEM and TEM of Pt-C replicas are best suited to image the overall morphology of microcrystals. However, owing to the decoration effect of Pt-C on the crystal faces, TEM of Pt-C replicas is superior at resolving nanoscale surface structures, including the development of new faces and the different microtopography among nonequivalent faces in microcrystals, which cannot be revealed by FE-SEM. In conjunction with SEM, Pt-C replica provides the evidence that crystals grow in diverse and face-specific modes. The TEM imaging of Pt-C replicas has nanoscale resolution comparable to AFM. AFM yielded quantitative information (e.g., crystallographic orientation and height of steps) of microtopographic features. In contrast to Pt-C replicas and SEM providing three-dimensional images of the crystals, AFM can only image one individual cleavage or flat surface at a time.

Here, we describe the development of an inexpensive and versatile manipulation system for in situ experiments in a field emission scanning electron microscope based on a parallel-guiding plate-spring mechanism and low cost materials. The system has been tested for a wide range of applications, such as collecting, moving, and positioning particles, fabricating atomic force microscopy tips based on carbon nanotubes, and characterizing individual nanobjects. The nanomanipulation results demonstrate that there are many opportunities for the use of physical manipulation in the bottom-up approach to fabrication of nanodevices.

This issue of Microscopy and Microanalysis presents nine of the articles from the 9th Workshop of the European Microbeam Analysis Society (EMAS) on “Modern Developments and Applications in Microbeam Analysis” held in conjunction with the 3rd Meeting of the International Union of Microbeam Analysis Societies (IUMAS) in Florence, Italy, on May 22–26, 2005.

Silicon-germanium thin films have been analyzed by EDS microanalysis in a field emission gun scanning transmission electron microscope (FEG-STEM) equipped with a high angular dark-field detector (STEM/HAADF). Several spectra have been acquired in the same homogeneous area of the cross-sectioned sample by drift-corrected linescan acquisitions. The Ge concentrations and the local film thickness have been obtained by using a previously described Monte Carlo based “two tilt angles” method. Although the concentrations are in excellent agreement with the known values, the resulting confidence intervals are not as good as expected from the precision in beam positioning and tilt angle position and readout offered by our state-of-the-art microscope. The Gaussian shape of the SiKα and GeKα X-ray intensities allows one to use the parametric bootstrap method of statistics, whereby it becomes possible to perform the same quantitative analysis in sample regions of different compositions and thicknesses, but by doing only one measurement at the two angles.

During lab-scale experiments on the reforming of methanol by means of water at supercritical conditions (T > 374°C, p > 22.1 MPa), a tubular reactor with a titanium liner was exposed to an aqueous solvent containing methanol (5 wt%) and KHCO3 (0.3 wt%). At the end of the run, a fibrous precipitate was found at two positions in the reactor. The material was studied in a field emission scanning electron microscope equipped with an energy dispersive X-ray analysis unit (FESEM/EDX). A thin-film support technique using carbon-filmed TEM grids was applied to perform scanning transmission-type imaging (STEM-in-SEM operation) and transmission current measurements. The analysis of the hydrothermally grown fibers resulted in a potassium titanate species composed of approximately K2TiO3, which has been confirmed by X-ray diffraction (XRD).

Zinc oxide (ZnO) nanoparticles have been produced using precipitation methods from ethanolic solution. Rare-earth metal doping was performed, and the effect of lithium codoping on the luminescence properties of the rare-earth doped products was assessed. The resulting particles were characterized using cathodoluminescence and scanning electron microscopy. It was found that lithium significantly enhanced the cathodoluminescence signal from the rare-earth ions, which has been attributed to the increased integration of the rare-earth ions into the ZnO structure. The nanophase ZnO products were also annealed in argon, hydrogen, and oxygen, with hydrogen being the most successful for removing the broad defect emission present in as-grown samples and enhancing the ZnO near band edge emission.

The carbon contents in carburized steels were investigated by electron probe microanalysis (EPMA) for a range of carbon levels in the solid solution less than 1 wt%. This article describes the difficulties encountered with the classic analytical procedure using the k ratio of X-ray intensities and the φ(ρz) model. Here, a suitable calibration curve method is presented with emphasis on the metallographic study of standard specimens and on the carbon decontamination of samples.

This article describes the effects of surface controlled decarburization on the structure of a nitrided steel. Samples of quenched and tempered 40CrMo4 steel were decarburized by air heat treatment (800–900°C) at different depths and submitted to gaseous nitriding. The microstructure of surface layers after decarburization and nitriding were investigated by optical (OM) and scanning electron microscopy (SEM). The nitrogen and carbon profiles in the diffusion layers were determined by a scanning electron microscope equipped with a wavelength dispersive spectrometer (EPMA-WDS). The effect of nitriding was determined by microhardness measurements. The increasing of time and temperature of decarburization slightly affect the surface hardness values, while case hardness depths decrease. In all the specimens, the nitriding depth, as determined by the WDS nitrogen profile, is larger than the one determined by the hardness profile.

We describe the recent introduction of low energy X-ray emission spectrometry as a metrology technique to control the fabrication process in the integrated circuit industry. The benefits of this particular analytical method and the wide field of potential applications are addressed.

Microanalysis on the 10-nm level using imaging, diffraction, and spectroscopy of slow photo-emitted and reflected electrons is discussed. The instrumentation that uses a cathode lens is briefly reviewed, and a number of applications illustrate the power of this microanalysis method.

The focus of this review is on trace-element quantitation of microstructures in solids. This review is aimed at the nonspecialist who wants to know how secondary ion mass spectrometry (SIMS) quantitation is achieved. Despite 35 years of SIMS research and applications, SIMS quantitation remains a fundamentally empirical enterprise and is based on standards. The most used standards are “bulk standards”—solids with a homogeneous distribution of a trace element—and ion-implanted solids. The SIMS systematics of bulk standards and ion-implanted solids are reviewed.

Deposition of Ti/N compositionally gradient film onto Ti-6Al-4V alloy substrates was carried out by reactive DC sputtering, not only to improve the blood compatibility of the alloy but also to relax the stress concentrated at the interface between the film and the alloy substrate. The compositional gradient was realized by varying continuously the nitrogen content in Ar-N2 sputter gas during deposition. In Auger electron spectroscopy (AES) analysis, Auger spectra were acquired in the N(E) mode using the beam brightness modulation (BBM) method to overcome the problem of the peak overlap of the principal Auger nitrogen transition peak (N-KLL) with one of titanium peaks (Ti-LMM). The deposited film appeared to be uniform and adhesive. TiN formation at the surface of the film was assumed, because of its yellow gold color and the X-ray diffraction (XRD) pattern for it. Under scanning electron microscopy, it was found that the surface had fine particles dispersed on a smooth accumulated deposit and that this depositing method improved the structural property of the film at the surface. According to AES in-depth profiles, the nitrogen (N) concentration in the film gradually decreased in the depth direction from the surface toward the alloy, confirming that a Ti/N compositionally gradient film had formed on the alloy substrate.

Calendar of meetings and courses.