It is well known that chemical bonding affects elemental x-ray emission spectra. The spectra of low atomic number elements show energy shifts which depend on the bonding of the element. To observe these shifts, a high resolution wavelength dispersive (WDS) x-ray spectrometer is required. Intensity variations of the L series can be observed with an EDS system which also show chemical effects.

The L Alphal and the L L radiations are produced from a vacancy in the L III shell. Normally the L L line is about 5 to 6% of the intensity of the L Alphal line. However, in the atomic number range of Z=21 to 28, it is easily observed that the L L line becomes more intense. The L Alphal is no longer present at Z=20. These intensity changes are due to the outer electron shells of these atoms being unfilled. The L Alphal comes from the L3-M5 transition, while the L L comes from L3-M1 transition. The M5 (3d level) of the M shell is partially filled for Z=21 to 28; empty for Z<21and full for Z> 28. Holliday observed a Ti LL which was 17% greater than the Ti L Alphal.

Analysis parameters for an electron microprobe are numerous, and the accuracy of the quantitative analysis is very sensitive to the selection of these experimental conditions. The expert system intends to optimize the choice of each analysis parameter as well as to automate the phases of a quantitative analysis on all kinds of materials. To summarise, the aim of the expert system is to simplify the procedures, improve the accuracy of results and control the analysis time. The figure 1 illustrates the various stages of the expert system.

The starting point of the expert system is an interactive questionnaire concerning the sample,( ie, what is already known), and about the expectations on the analysis,( ie, the accuracy of the results and/or the duration of the analysis required by the operator). Then, the expert system performs a semi-quantitative analysis on the sample. Based on the acquisition of a wavelength qualitative spectrum, this method is a way to obtain the sample composition in a short time with the advantages of the WDS system, and with a reasonable accuracy.

Japanese color woodblock prints ("ukiyo-e") from the Edo (1615-1868) and Meiji periods (1868- 1912) are among the most celebrated examples of color printmaking in the world. Full-color prints became technically and commercially viable around 1765. Traditional ukiyo-e colorants were watersoluble, uniform, translucent, organic (vegetal) and inorganic pigments of very small particle size. (Synthetic colorants were also introduced from the West in the 19th C, probably beginning with "Prussian blue" in the 1820s.) A pigment was applied with a brush to a color block, and then rice flour paste was mixed with the pigment to thicken it, facilitate control and rubbing into the paper, improve the uniformity of the colorant, and avoid a dry or granular texture. The dampened paper, sized with cooked bovine skins and alum, was then placed on the block (aligning with registration marks cut into the blocks). The colorants were then pressed into the paper by rubbing a bamboo pad against the back of the paper so that the colors were absorbed on the front surface.

Studies of Pd foil cathodes have indicated that when electrolyzed for long times in electrolytes containing both deuterium and hydrogen ions along with sulfuric acid, the cathodes undergo compositional, topographical, evolutionary, and isotopic changes. The results reported here describe the changes which are produced in Pd cathodes after only a few minutes of electrolysis.

In June 1993 a cold-rolled, Pd (AESAR lot #12E06) cathode of 40μm thickness was submerged at one end into an electrolyte containing 20 ml D2O and 3.5 ml H2SO4 and electrolyzed for six minutes at about 0.6 A/cm2 and 3.65 V. An identical Pd cathode (cut from the same strip) was submerged at one end into an electrolyte containing 20 ml H2O and 3.5 H2SO4 and electrolyzed for six minutes using 0.6 A/cm2 and 4.11 V. A Pt foil acted as the anode in each case. The two cells were connected in series. An ionic current flowed between the electrodes for each system as the voltages were applied.

A series of experiments were conducted with titanium cathodes and platinum anodes electrolyzed in heavy water-sulfuric acid electrolyte in closed cells. Each of the cathodes in these experiments was cut from the same titanium foil (99.99% Ti). Each cathode underwent a pre-experiment and a post-experiment SEM (ISI-SS40) and EDS (LINK AN10000) analysis. Of the eight experimental cathodes, three showed post-experimental evidence of localized chemical changes. This is consistent with other findings from this lab. Results obtained on one of these cathodes are presented here.

This cathode was electrolyzed for 115 hours at 0.40A (current density about 2A/cm2). The cathode was ultrasonically cleaned in deionized water for five minutes prior to the pre experiment analysis. Fig. 1 shows the smooth surface of the cathode before electrolysis. No other elements besides titanium were found. After electrolysis in 19.4g D2O +l.0g H2SO4 the cathode was removed from the cell and rinsed by gentle agitation in deionized water for several minutes.

Conventional water treatment plants that use alum (aluminum sulfate) as a coagulant have been dealing with the issue of residual alum carry over from the treatment plant into the distribution system. The basic product formed whe alum is added to water is aluminum hydroxide floc. This floc grows in size and density as it captures suspended particulates and then is settled out. Smaller floc aggregates that pass through the settling process are in the most part removed by sand filtration. However due to the amphoteric characteristics and solubility properties of aluminum alon with it’s many different compounds, carry over of aluminum compounds through the filter is a phenomena that is a great concern to the water industry. These residual aluminum compounds produce small hydroxide floes that coat the inner surfaces of distribution pipes causing head loss or increased energy requirements for water pumping.In addition phosphate compounds (poly and ortho blends) have recently been added to the distribution system to reduce the leaching and corrosion of lead and copper from pipes.

Solder joints provide mechanical and electronic connections between solders and components for various levels in microelectronic package. However, due to different thermal expansion coefficients and elastic modulus of the associated materials, solder joints are susceptible to fatigue degration, microcracks and fracture. The solder joint reliability is, therefore, critical in the evalution of the joint quality. Recently, the employment of lead-free solder is attractive due to the environmental concern of the Pb-containing solder. Hence, the investigation on the unleaded solder joint is of practical importance in the field of microelectronic package.

Intermetallic compounds (IMC), which form and grow between solders and metallizations, are considered to be a source of mechanical weakness for its brittleness and different coefficient of thermal expansion from the metallization or the solder.

Abstract

Cryogenic detectors with excellent energy resolution and low energy threshold far beyond the level of semiconducting detectors open a variety of new. applications in physics including search for Dark Matter in the universe [2], neutrino physics [3], and IR-, UV- and X-ray astrophysics [4, 9]. Interdisciplinary fields where cryogenic detectors have already shown promising results are the detection of biomolecules [5] and X-ray spectroscopy at synchrotron beam lines [6] and in scanning electron microscopes (SEMs) [7]. For both, astrophysical and analytical use, the development of high resolution microcalorimeters based on iridium/gold phase transition thermometers and aluminum tunnel junctions for use in a compact and universal detector system was initiated.

Our cryogenic microcalorimeters consist of an absorber, a temperature sensor and a weak coupling to a heat sink. An X-ray photon interacts with the absorber and raises its temperature. The sensor measures the temperature increase and the system then, mediated by the coupling, relaxes back to its operating temperature.

Introduction

Radiation curing of polymers, by UV light or E-beam, is of growing interest in the state-of-the-art industry. Radiation curing is solvent free and leads to important energy and money savings. Improved materials characteristics, better control of doses and more accurate application allow radiation curing to take a big part of the surface coating industry and, for the last ten years, the polymeric and microelectronics (lithography) industry. But behaviors of polymers under radiant source is often empirically characterized. In this abstract, it is proposed a way to obtain accurate energy distribution from Monte Carlo simulations. For bulk or thin polymeric films, it is therefore essential to simulate energy distribution, in order to foresee what happens in the sample.

Results

CASINO is a single scattering Monte Carlo Simulation of electroN trajectory in sO lid -particularly designed for low energy beam interaction in a bulk and thin foil.

In the semiconductor industry the importance of Computer Aided Materials Analysis (CAMA) is growing rapidly due to ever decreasing feature sizes on semiconductor wafers. Due to the fact that the excitation volume is often larger than the typical feature size on a processed state-of-the-art semiconductor wafer it was necessary to extend SeSAME, a Monte Carlo simulator for arbitrary 2- dimensional geometries, to be able to handle arbitrarily shaped 3-dimensional structures. This is achieved by using a so called multi-quadtree approach for the discretization of 3-dimensional geometries.

A multi-quadtree consists of several parallel arranged modified quadtrees. This means, an arbitrarily shaped 3-dimensional structure is divided into parallel slices of constant geometry in direction perpendicular to the quadtree plane. The number of such 2-dimensional slices and the thickness of these slices is solely limited by the available memory. Therefore, really 3-dimensional structures may be resolved in principal with any resolution.

Here we demonstrate sub- 1.5 Å resolution in compositionally sensitive high-angle annular dark-field (HAADF) (“Z-contrast”) imaging. For the first time this has been achieved on a 200 kV field-emission transmission electron microscope (FEGTEM), the JEOL JEM-2010F. With a Gatan imaging filter, this type of instrument is then capable of both analytical imaging and electron energy-loss spectroscopy at similar spatial resolution as in the 300 kV dedicated STEM.

The Z-contrast imaging technique has a spatial resolution given by the size of the electron probe. When used to image periodic specimens and their defects, the effective incoherent nature of the Z-contrast method leads to higher resolution for given lens Cs, higher sensitivity to atomic number and easier qualitative image interpretation than in HRTEM.In practice, the ability to form a small (atomic resolution) probe depends on the brightness of the electron source, and achieving low enough levels of mechanical and electrical instabilities that otherwise incoherently broaden the probe.

The trend of replacing trench and stack capacitors in a dynamic random access memory (DRAM) with a planar configuration has stimulated the development of high dielectric constant materials with reliably low leakage current and high dielectric breakdown strength. In this regard, high dielectric constant materials, such as PbZrxTiyO3(PZT), BaTiO3, SrTiO3, PbTiO3, and BaxSr1-xTiO3, have been extensively investigated as dielectrics in the last few decades. Of these, the sol id-solution quaternary BaxSr1-xTiO3, (BST) combines the high dielectric constant of BaTiO3, with the structural stability of SrTiO3, is one of the most promising materials for DRAM cells in very large-scale integrated circuits. BST shows a paraelectric phase for x<0.7 at room temperature, which provides additional features such as no aging or fatigue effects from ferroelectric domain switching. However, so far, there have been few studies of the interfaces between BST and the substrates, particularly at the atomic-resolution level.

MBE techniques allow the fabrication of exceptionally sharp compositional changes such as delta doped layers in semiconductors. Producing these spatially confined doped layers is critical to many innovative device designs. The spatial confinement of these delta doped structures can be less than the measurement resolution of the currently standard SIMS and RBS techniques. This allows only the upper limits on the layer width to be measured. These SIMS and RBS methods are also inadequate for the two dimensional information desired for future device design and development. More recently developed techniques such as Scanning Capacitance Microscopy and spreading resistance measurement give two dimensional information but have similar spatial resolution issues. The Z-contrast nature of Annular Dark Field (ADF) imaging with the complimentary technique of Electron Energy Loss Spectroscopy (EELS) in the Scanning Transmission Electron Microscope (STEM) shows promise for two dimensional dopant profiling with spatial resolution on the atomic scale.

Electron energy-loss spectroscopy (EELS) in the transmission electron microscope (TEM) analyzes the energy distribution of the probe electrons after they have lost energy within the sample. The resultant energy-losses are characteristic of elemental, chemical, and dielectric properties and are typically measured in one of two ways. Parallel-detection EELS spectrometers (PEELS) acquire large energy ranges of the energy-loss spectrum simultaneously for rapid acquisition of spectral data at a single area. In contrast, the energy filtering TEM (EFTEM) acquires only a single energy band at once, but does so for thousands or even millions of image pixels simultaneously.

Spectrum imaging (SI) involves acquisition of detailed spectroscopic data sufficient for rigorous analysis at each pixel in a digital image. (Fig. la) A STEM EELS spectrum image “data cube” can be acquired by stepping a focused electron probe to each pixel and filling the spectrum image one spectrum at a time.

The ability of modern TEMs to acquire a series of energy filtered images opens up new possibilities in energy loss compositional analysis. In particular, an electron spectroscopic imaging (ESI) series may be treated as a 2-D array of spectra whose resolution is dictated by the step size of the image series, as illustrated in Fig (a). This allows standard spectroscopic analysis techniques to be used on the extracted ‘image-spectra’, such as the removal of plural scattering by deconvolution. Examples of this are given in Fig (b) and (c), which show how Fourier-log and Fourier-ratio deconvolution can be used to recover the single scattering distribution (SSD) from both the low-loss and core-loss regions from a Cr specimen. A pure elemental sample is ideal for testing the validity of such analysis techniques for quantitative compositional mapping, and more details of this method will be published elsewhere. Further, for many simple metal systems, such as steels and alloys, and for simple semiconductors it is possible to model the plasmon contribution using a simple Drude-Lorentz model.

The dependence of diffraction contrast on electron energy loss is an important relationship that needs to be understood because of its potential effect on energy-filtering transmission electron microscope (EFTEM) images. Often when either a two-window jump-ratio image or a three-window elemental map is produced diffraction contrast is not totally eliminated and contributes to the intensity of the final EFTEM image. Background removal procedures often are unable to completely account for intensity changes due to dynamical effects (i.e., elastic scattering) that occur between images acquired at different energy losses, leaving artifacts in the final EFTEM image.

In this study, the relationship between diffraction contrast and electron energy loss was investigated by obtaining EFTEM images of a bend contour in aluminum in 100 eV increments from 0 to 1000 eV (Fig. 1). EFTEM images were acquired a JOEL 2010F FEG TEM with a Gatan imaging filter (GIF) at a microscope magnification of 8 kX using a 1 eV/pixel dispersion, 2X binning (512 x 512) and exposure times ranging from 0.25 s for 0 eV energy loss up to 132 sec for 1000 eV energy loss.

The small electron probe available in a scanning transmission electron microscope (STEM), when combined with X-ray energy dispersive spectroscopy (XEDS), enables the acquisition of 2D compositional maps with high spatial resolution and sensitivity. In addition to the spectroscopic information available, images sensitive to atomic number (so called Z-contrast images) can be acquired simultaneously using high-angle annular dark field imaging (HAADF). These capabilities make the STEM an ideal tool to study elemental distributions in catalysts containing 1-2 nm sized metal clusters within a support of low atomic number. The material examined in this work comprises of mesoporous silica in a honeycomb structure with channels of ˜3 nm diameter (designated MCM-41) in which nano-clusters of the bimetallic Pd6Ru6 have been introduced into the channels using metal-cluster carbonyls as precursors. Details of the specimen preparation are similar to that outlined by Shepard et al. for a Cu-Ru bimetallic catalyst.

Fig. 1 shows (a) a bright-field (BF) image, (b) a HAADF image and (c-f) X-ray elemental maps acquired on a VG 603 STEM, operated at 300 keV with probe size of ˜1.4 nm (FWTM) and probe current of ˜0.6 nA.

A common impurity in polycrystalline commercial alumina is Si since silica is often added as a sintering aid. There have been several studies on impurities in alumina, and substantial degree of grain boundary segregation has been found to occur. Alumina-metal composites have found several applications especially in the electronic industry and consequently systems such as alumina-copper have been studied exhaustively. However, the role of impurities in metal-alumina composites has not been fully explored. Studies of Pt-alumina composites has shown that silicon is present at the interface of vacuum, diffusion bonded samples. Our earlier studies have shown that Si indeed segregates to the triple junctions and grain boundaries in alumina and in alumina-copper composites, often Si segregates to the metal-ceramic interfaces as well. This investigation concentrates on the distribution of silicon in copper-alumina in comparison to aluminum-alumina composites.

The metal-ceramic composites were prepared by diffusion bonding 99.99% pure metal foils sandwiched in between commercially available sintered alumina (∼99.5% pure) substrates for several hours in vacuum.

In conventional x-ray mapping, energy regions are defined to straddle the N x-ray spectral peaks of interest. At each pixel position in the digital image, counts are recorded from each energy region and thus give rise to N element maps of intensity distributions over the field of view. Fig. 1 shows an example set of x-ray maps from a polished test sample. It is clear from the images that there are circular regions of differing composition but it is not immediately obvious which regions have the same composition. Furthermore, in a real sample, phases are unlikely to appear in such regular patterns so the correlations between maps are in general much more difficult to notice.

It is possible to choose two x-ray maps and generate a 2D scatter plot showing the intensity values in both maps for all pixels in the image.

A topic of growing importance is the nano-structuring of inorganic materials by exploiting interactions with self assembling polymers. One example are multiphase polymers.

Driven by the mixing enthalpy, most polymers phase separate below their critical solution temperature. The components of block copolymers are covalently linked, restricting separation to microscopic length scales. Depending on composition, block copolymers form different equilibrium morphologies representing the energetically most favorable balance between- interfacial area and chain conformation.

Mass thickness contrast of polymers is often weak and conventional TEM can thus fail to characterize the morphology unless selective staining methods exist. This is the case for the poly(isoprene)-b-poly(ethyleneoxide) diblock copolymer system (PI-b-PEO) used as a structure directing agent and to provide solubility (see below). Fig. 1 shows the micro-domain morphology of PI-b-PEO where the rubbery phase is selectively stained with OsO4 .

Hybrid materials are obtained by addition of an inorganic precursor to a solution of PI-b-PEO in a "mutual" solvent.