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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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