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The short-range order of molten silicon was investigated in a wide temperature range from 1893 K down to 1403 K, corresponding to an undercooling of 290 K. Energy-dispersive x-ray diffraction was used in combination with electromagnetic levitation. The structure factor and the pair correlation function were determined as a function of temperature from the experimental data. A small hump on the higher wave vector side of the first peak in the structure factor was observed at all temperatures. The position of the first peak in the pair distribution function shifted to shorter distances and its height increased gradually with decreasing temperature. No discontinuous behavior was observed in the entire temperature range investigated.

An x-ray absorption fine-structure (XAFS) spectroscopy beamline, BL01B1, was installed at a bending magnet source at SPring-8 and has been open to users since October 1997. It was designed for XAFS experiments covering a wide energy range. Position tables and automatical control programs were established to adjust the x-ray optics and achieve the designed performance of the beamline under each experimental condition. This has enabled conventional XAFS measurements to be made with a good data quality from 4.5 to 110 keV. Keywords: XAFS; high-energy; beamlines.143 radiation light will be reported elsewhere. The results show that the target specifications for the measured beam have almost been completely achieved except for sagittal focusing: a photon flux of 109-10 ~ phs/s with AE/E of <2x 104, a vertical beam size focused by a mirror of < 0.2 mm, and a ratio of the higher harmonics contaminant of < 10 .5 with mirrors.To achieve the designed performance of the beamline in a wide energy range, the beamline optics should be adjusted to the optimal position for each experiment. Because rearranging the monochromator and/or mirrors involves the realignment of many components, such rearranging can be done a few times per day. To achieve quick and easy adjustment, we prepared tables at the positions of the optical components and developed automatic control programs. This report gives an overview of the beamline status and some representative results highlighting the performance of BL01B 1.

Extended x-ray absorption fine structure (EXAFS) above the Ta L3 edge on tantalum oxide capacitor films has been measured. Tantalum oxide films were prepared by low-pressure chemical vapor deposition (CVD) using a Ta(OC2H5)5 and O2 gas mixture. Four kinds of tantalum oxide films were studied: as-deposited (amorphous), N2 annealed (crystalline), dry O2 annealed (crystalline), and O2-plasma annealed (amorphous). From EXAFS analysis, differences in the local structures of tantalum oxide capacitor films, in terms of oxygen deficiency around Ta, were observed in the various annealed films. The leakage current characteristics of tantalum oxide capacitors correspond to the differences in the local structures around Ta.

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A one-kilometer long synchrotron radiation beamline with an x-ray undulator source was completed at SPring-8. The beamline was planned to facilitate various applications of a wide-area coherent x-ray beam, development of bi-crystal x-ray interferometers for gravitational red-shift measurement and development of highly sensitive diagnostic methods of accelerator dynamics. This paper reports the structure of the long beamline as well as some selected first results including phase contrast imaging and diffraction imaging applications.

The newly installed BL28XU beamline at SPring-8 is dedicated to in situ structural and electronic analysis of rechargeable batteries. It supports the time range (1 ms to 100 s) and spatial range (1 mm to 1 mm) needed for battery analysis. Electrochemical apparatus for battery charging and discharging are available in experimental hutches and in a preparation room. Battery analysis can be carried out efficiently and effectively using X-ray diffraction, X-ray absorption fine-structure analysis and hard X-ray photoelectron spectroscopy. Here, the design and performance of the beamline are described, and preliminary results are presented.

A highly reliable ulirathin tantalum oxide capacitor is fabricated by using oxygen-plasma annealing after the film deposition. A tantalum oxide film is deposited on a nitrided polycrystalline silicon surface using a mixture of pentaethoxy-tantalum [Ta(OC2Hs)5] and oxygen gas. The films are annealed in an oxygen-plasma at less than 400°C. The oxygen-plasma annealing greatly reduces the leakage current through tantalum oxide capacitors and produces better time-dependent dielectric breakdown characteristics than either dry O~ annealing or two-step annealing (oxygen-plasma + dry 02 annealings). The reason for the excellent electrical properties is examined using secondary ion mass spectrometry, extended x~ray absorption fine structure spectroscopy, and transmission electron diffraction patterns. Analytical results show that the oxygen-plasma annealed tantalum oxide films are densified by the elimination of carbon and hydrogen and by the repair by oxygen of vacant sites in the as-deposited films, as the films remain amorphous during oxygen-plasma annealing. In addition, oxygen-plasma annealing suppresses thickening of the interface layer between the tantalum oxide film and polycrystalline silicon bottom electrode. Therefore, highly reliable ultrathin tantalum oxide capacitors with an SiO2 equivalent thickness of less than 3 nm can be fabricated by using oxygen-plasma annealing.