The synchrotron x-ray source provides a unique opportunity to observe many “in-situ” processes. The formation of the “short-lived” intermediate species, Ta2C, during the combustion synthesis of TaC, has been observed and reported by monitoring the Bragg diffraction peaks of the reactants and products, Similarly, the synthesis of the ferroelectric material, BaTiO3, and subsequent phase transfonnation from cubic to tetragonal have also been investigated. These experiments would not have been possible without the high incident x-ray flux available at a synchrotron source.

There are several methods for the measurement of retained austenite in steels, which influences mechanical behavior and corrosion resistance of steels. Among them, X-ray diffraction methods using a wide angle goniometer or X-ray stress analyzer are commonly used because the methods are non-destructive, giving useful information about residual stress or lattice strain as well.

X-ray characterizations of coals and coal products have occurred for many years. Hirsch and Cartz measured the diffraction from several coals over the reciprocal space region from s = 0.12 Å-1 to 7.5 Å-1 where s = (4πλ) sine). In these studies, a 9 cm powder camera was used to study the high angle region, and a transmission type focussing camera equipped with a LiF monochromator was used for the low angle measurements. They reported that the height of the graphene peak (ca. 3.5 Å) measured for each coal is proportional to the % carbon in the coals. Hirsch also suggested that the ontyberem anthracite (94.1% carbon, 3.0% hydrogen, and 5.3% volatile matter with a specific gravity of 1.46) has a lamellar diameter of ca. 16 Å corresponding to an aromatic lamellae of ca. C87. For coals with lower carbon content, Hirsch proposed much smaller lamellae; C19 for a coal with 80% carbon, and C24 for a coal with 89% carbon.

Capillary collimators have found a number of uses in fluorescence, diffraction and other x-ray fields. Most of these applications are realized with single, straight glass capillaries. Focussing of synchrotron x-radiation beams has been shown with tapered capillaries. In addition, numerous straight and bent capillaries, bundled into lens-like optics, offer experimenters many other possibilities for better use of the x-radiation from tubes, synchrotron radiation, and plasma sources or the x-ray intensity collected from samples.

In the late 1980s, a new X-ray focusing system, X-ray lens, capable of adjusting and controlling high power, white X-ray beams, has been created. This X-ray lens can collect X-rays in a large angle range, increasing the utilization efficiency of an Xray source. It can focus X-rays into a small spot, improving X-ray power density 104 to 106 times when compared to the same source at the same distance without the focusing system. It can also transfer diverging X-ray beam to a nearly parallel one. These properties make the focusing system potentially useful in many Xray applications.

X-ray reflectors bent into a transcendental profile have been considered. When combined with a log spiral cut-off filter/reflector, these reflectors can produce either parallel beams or focused beams.

The characteristic 17.441 keV Mo-Kα tube line yields an exceedingly strong reflection at a Bragg angle of 6.0710 on Highly Oriented Pyrolytic Graphite (IIOPG). Using doubly bent toroidally shaped crystals we were able to concentrate the characteristic radiation from a Mo anode fine focus tube onto a small focal spot area of about 1 mm. FWHM diameter, as was observed by an X-Ray sensitive CCD. The radiation of the Mo anode fine focus tube is emitted at a take-off angle of 60 into a total solid angle with an aperture of 120. About 90 percent of this primary radiation solid angle can be used for the desired Bragg reflection on the designed toroidal crystal surface. This feature ensures the high beam intensity needed for special excitation problems.

A toroidal focLising W/Si multilayer and a planar W/Si multilayer were tested for the possible usefulness for the Energy Dispersive X-Ray Fluorescence Analysis (EDXXRF) of low Z elements.

A highly oriented pyroliiic graphite crystal is commonly used as a monochromator for X-ray diffraction and fluorescence analysis (l)-(6). Improvements in the monocliromator performance is desired to increase the range of practical applications.

Micro-SRXRF (Synchrotron Radiation induced X-ray Fluorescence) is ti microanalytical technique which, utilizes an intense, polarized X-ray micro beam originating from the storage ring to induce X-ray fluorescence in a microscopic volume of the sample under investigation. The emerging fluorescent and scattered radiation is normally detected by an energy-dispersive Si(Li) detector. The recorded fluorescent spectra provide qualitative and quantitative information on the examined material yielding minimum, detection limits in the ppm and in favourable cases in the sub-ppm range at current SRXRF-facilities. Possible applications of synchrotron X-ray microprobes are the mapping of chemical elements in biological tissues, investigation of element migration and partitioning in geological systems, the analysis of individual microscopic particles and a variety of topics in applied research.

This is a review of Total reflection X-Ray Fluorescence (TXRF) applications for semiconductors. This review is limited to surface analysis of contamination for semiconductors and does not include chemical analysis in semiconductor processing. TXRF for surface analysis is a relatively new technology. One of the first publications occurred in 1986 using synchrotron radiation. Publications using commercially available TXRF instruments for semiconductor applications began in 1988. Today there are on the order of 100 TXRF instruments worldwide in the semiconductor industry. Since 1988 there have been about 100 publications in this field, but this number does not include numerous abstracts and publications in Japan where the majority of the commercial instruments are found today. The commercial instruments were developed for the primary application of characterizing the cleaning of planar silicon wafers, however, numerous unforeseen applications were developed by users and many of those applications are reported here. In essence TXRF has much broader application today in the semiconductor industry than supporting the cleaning of silicon wafers.

Total Reflection X-Ray Fluorescence Analysis (TXRF) has been proved to be well suited for the energy dispersive analysis of light elements using a special spectrometer, which is equipped with an energy dispersive detector having all properties for the detection of low energy radiation. The detection of the light elements is strongly influenced by the excitation source which should provide a large number of photons with energies near the K-absorption edge of these elements (0.2 - 3 keV). Various standard tubes with Be-window as well as a homemade windowless tube are compared, all differing in focal size, total power and anode material. Optimized excitation conditions are provided by synchrotron radiation meeting all requirements for excellent excitation of light elements in total reflection geometry such as high brilliance and ideal spectral distribution specially in the low energy region. A comparison of excitation with X-ray tubes as well as with synchrotron radiation is shown. Detection limits of 200 fg for Mg have been obtained with synchrotron radiation.

This article explores applications of total reflection x-ray fluorescence (TRXRF) to GaAs processes. The applications include determination of surface contamination and InGaAs layer thicknesses. Surface contamination can deteriorate device performance and can occur in starting substrates and in subsequent processing. We demonstrate that TRXRF is a quick, nondestructive method for identifying sulfur contamination on incoming wafers and low levels of metallic impurities from device fabrication. Variable angle TRXRF has been used to determine heterostmeture film thickness, measuring films of InGaAs on GaAs as thin as 4 nm.

A nickel-coated glass plate was used as a reflecting surface in the TRXF spectrometer with a log spiral bent cut-off filter. Optimal choice of the reflecting material has enabled us to lower the detection limit up to five times. A possibility to increase the spectrometer sensitivity by using an additional reflector bent into a transcendental profile to provide a required angular divergence of the exciting beam has been discussed.

Total reflection X-ray Fluorescence (TXRF) has been applied to the detection and quantification of metal contamination on the surface and near-surface regions of silicon wafers in the semiconductor industry The need for improving the sensitivity and detection limit of the TXRF technique is driven by the progress in producing thinner films and finer features in the development of larger Mbit DRAMS.

The development of intense synchrotron radiation sources during the last twenty years has enabled several types of x-ray spectroscopy and scattering techniques to come into practical use. One of the most significant methods for the characterization of extremely dilute samples is high resolution x-ray absorption-edge spectroscopy. The technique is usually divided into two separate methods according to whether the x-ray absorption near edge structure (XANES) or the extended x-ray absorption fine structure (EXAFS) is analyzed. XANES features are due mainly to bound-state electronic transitions just below, and on the low energy side of the edge, and to multiple scattering resonances on the top of the edge and at somewhat higher energies. EXAFS features are oscillations due to ejected photoelectron back scattering interference processes in the close vicinity of the absorber atom. XANES analysis is used to determine atom valence, atom site distortion from regular geometries, and other details of the atom site. EXAFS features can be analyzed to recover interatomic distances between the absorber atom and its first few shells of neighbors, as well as the number and types of these neighbors. Together these techniques can provide an atomspecific probe of die short-range structure within almost any type of condensed matter.

The x-ray source of our instrument is a rotating anode system with a silver target. It is flanged to a He-filled monochromator chamber. The photon energy of the x-rays for the excitation of characteristic specimen radiation can be tuned continuously from IkeV to 30 keV. The cross-section of the beam - monochromatic or polychromatic tube radiation - leaving the monochromator chamber is variable within 0.1 and 100mm2. A Be-window separates the evacuable specimen chamber from the monochromator chamber. The specimen holder allows for a linear movement of the specimen in x- and y-direction normal to the beam of incident x-radiation and allows a laterally resolved analysis. A rotation around an axis normal to the incident x-ray beam enables investigations under variable incidence- and take-off angles. X-ray detection is performed by an energy dispersive system.

Many light and ultra-light element analysis problems have been addressed by X-ray fluorescence. Recent innovative features of X-ray spectrometers have extended the applicability of X-ray fluorescence to ultra-light element analysis. Sensitivities have improved through the use of a newly developed end window X-ray tube. Selection of analyzing optics conditions optimize to some degree the sensitivity/resolution/intensity problems. Instrument stability is greatly improved by simply monitoring and controlling the vacuum within the analyzing chamber. Data are presented to illustrate the effects of these novel instrument components as well as describing several new application techniques for ultra-light element analysis.

In X-ray fluorescence (XRF) analysis, one of the major problems is the correction for matrix effects (absorption and enhancement). One of the solutions proposed was the use of influence coefficients, which are numerical coefficients that correct for the effect of each matrix element on the analyte. For many years, these coefficients were considered as an empirical approach having little connection with X-ray fluorescence theory. They were considered useful only when no other alternative was available to solve the problem of matrix effect.

It will be demonstrated that the Lachance-Traill, and Lucas-Tooth and Price matrix correction algorithms can easily be applied to spreadsheet stored XRF data.

The structure of spreadsheet stored data in Quantitative XRF Analysis, the utilization of built-in spreadsheet functions essential for data processing and the utilization of Spreadsheet Graphics for plotting of corrected and uncorrected XRF data will be presented.

Development of modern Electronic Spreadsheets has reached the point where they can readily be used for almost any type of laboratory task, including: Data Plotting, Statistical Data Analysis, Report Writing and Publishing, Slide Presentations, etc. This valuable tool can easily be added to older equipment that usually lacks sophisticated XRF software. It can also become an auxiliary tool to modern XRF spectrometers equipped with advanced XRF software.

The spreadsheet approach gives the analyst freedom of choice to process data according to personal/analytical preferences circumventing the rigidity of software supplied with the equipment. The spreadsheet approach also possesses educational value since it presents the basic ingredients of Matrix Correction in clear and concise table fashion. Addrtionaliy, the spreadsheet program is an excellent tool for demonstrating and evaluating different matrix correction models commonly used in X-ray Spectroscopy.

It will also be shown tliat Spreadsheet Graphics are capable of handling the two-theta scans of XRF or XRD data gathered from older DEC/PDP-11 based Rigaku Equipment. This results in excellent hard copies of the two-theta scans, regardless of the output device.

A mathematical background leading to the spreadsheet approach was partially presented in the paper “A mathematical comparison of the Lachance-Traill Matrix correction procedure with statistical multiple linear regression analysis in XRF applications” (41st Annual Denver X-ray Conference, Colorado Springs, 1992).