[en] In principle the brilliance of synchrotron radiation x-ray beams combined with a high degree of linear polarization allows to reach at the same time low LLDs, mapping of the impurity distribution and chemical identification for elements as light as Na. The TXRF facility at the European synchrotron radiation facility is installed along a beamline dedicated to industry and is designed to reach ultimate detection limits of 6 x 10⁷ at/cm² in selected areas, or to map the concentration of contaminants with LLD in the scale 10⁹ at/cm². In the present configuration the facility works in vacuum with a single element detector. Loading, unloading and pump down of wafers is completely automatic. Typical DDLs are of few 10⁹ at/cm² for Na and Al and 10⁸ at/cm² for transition metals. Absorption spectra (XANES and EXAFS) of TM help in the defining the chemistry of the contaminant. (author)

[en] A TXRF industrial facility for the mapping of trace impurities on the surface of 300 mm Silicon wafers is presently under construction at the ESRF, European Synchrotron Radiation Facility, in Grenoble (France) and its commissioning phase will start at the end of 1998. The elements to be detected range from Na to Hg with a target routine detection limit of 10⁸ atoms /cm². The facility is the result of a collaboration between the ESRF and some of the major European semiconductor companies in the framework of the MEDEA consortium. Preliminary experiments at ESRF reached a detection limit of 1.7x10⁸ for Ni atoms (17 fg) in not optimised experimental conditions. The facility will improve the detection limit by a factor of 50. However, this gain in sensitivity will be traded in the possibility of mapping the surface of 300 mm wafer with a resolution of 500 pixels and a throughput of three wafers/h

[en] The pursuit of smaller and smaller circuitry in device manufacturing imposes tight limits on the surface contamination of the wafers. TXRF, Total Reflection X-ray Fluorescence, is the leading technique in device industry for detecting surface impurities. However, laboratory equipments have reached their limit, and the common practice then for reaching the desired sensitivities of ∼109 atoms per cm square, equivalent to 10-6 monolayers, is then to proceed to pre-concentration of the impurities. This operation erases any information on the localisation of the impurities, making much more difficult the identification of their origin. Centralised facilities based on Synchrotron Radiation extend the reach of classical TXRF machines offering new opportunities both in terms of ultimate sensitivity, lateral resolution and detectable range of elements. In this contribution we will describe a dedicated TXRF instrument operational at the European Synchrotron Radiation Facility in Grenoble along with its performances, limitations and future developments

[en] Based on the direct structure determination of the silicide formed at room temperature from <1 monolayer of Ni deposited on Si(111) and from Ni coverages up to five monolayers, a model for silicide growth and interface formation is presented. The model forms a basis for understanding many of the photoemission, ion scattering, and microscopy results from this system

[en] Undulators installed in third-generation synchrotron radiation facilities will provide photon beams with high brilliance and large power densities. The optical quality of these beams allows, in principle, the use of simpler optical systems for focusing and monochromatization. In practice the performance of the optical elements is the physical limit to the exploitation of these high brilliance beams. In double-crystal monochromators the bending of the first crystal due to the thermal load and the anticlastic effect on the sagittally bent second one are among the main sources of problems on the overall performances. Here we have considered a double-crystal monochromator with a meridionally bent first crystal followed by a sagittally focusing one. We show that this geometry offers correction either of thermal loads and anticlastic distortions, or minimization of the bandpass or tangential focusing. This can be particularly useful on the high-energy range and for sharp Bragg reflections

[en] Synchrotron radiation total-reflection X-ray fluorescence (SR-TXRF) has been applied to the impurity analysis of Si wafers using a third-generation synchrotron radiation undulator source. A lower limit of detectability (LLD) for Ni atoms of 17 fg (1.7 x 10⁸ atoms cm^-2) has been achieved with an optical set-up based on an Si(111) double-crystal monochromator and a horizontal sample geometry. These first results are very promising for synchrotron radiation trace element analysis since we estimate that it is possible to lower the LLD by a factor of about 25 by employing appropriate optics and detectors. The use of a crystal monochromator opens new possibilities to perform absorption and scattering experiments (NEXAFS and X-ray standing-wave methods) for chemical and structural analysis of ultratrace elements

[en] The application of near-edge surface, extended x-ray absorption fine structure to the study of a clean surface is reported. Direct evidence is found for surface recrystallization of ion-damaged (amorphized) Si, whereas no such evidence is seen for evaporated (amorphous) Si. The procedures described here are applicable to almost all clean or adsorbate-covered surfaces

No abstract available

[en] We developed and optimised an optics-free Atomic Force Microscope (AFM) that can be directly installed on most of the synchrotron radiation end-stations. The combination of Scanning Probe Microscopies with X-ray microbeams adds new possibilities to the variety of synchrotron radiation techniques. The instrument can be used for atomic force imaging of the investigated sample or to locally measure the X-ray absorption or diffraction, or it can also be used to mechanically interact with the sample while simultaneously taking spectroscopy or diffraction measurements. The local character of these measurements is intrinsically linked with the use of the Atomic Force Microscope tip. It is the sharpness of the tip that gives the opportunity to measure the photons flux impinging on it giving beam position monitor features, or allows to locally measure the absorption coefficient or the shape of the diffraction pattern. As an example of the possibilities opened by the instrument we will show diffraction measurements performed on a Ge/Si island while being indented with the AFM tip providing local measure of the Young coefficient. Three ESRF beamlines are going to be equipped with this new instrument.

[en] The in situ combination of Scanning Probe Microscopies with X-ray microbeams adds a variety of new possibilities to the panoply of synchrotron radiation techniques. This paper describes an optics-free Atomic Force Microscope that can be directly installed on most of the synchrotron radiation end-stations for combined X-ray and atomic force microscopy experiments. The instrument can be used for atomic force imaging of the investigated sample or to locally measure the X-ray absorption or diffraction, or it can also be used to mechanically interact with the sample while simultaneously taking spectroscopy or diffraction measurements. The local character of these measurements is intrinsically linked with the use of the Atomic Force Microscope tip. It is the sharp tip that gives the opportunity to measure the photons flux impinging on it, or to locally measure the absorption coefficient or the shape of the diffraction pattern. At the end an estimation of the limits of the various techniques presented is also discussed.