FABRICATION OF A GROOVED SINGLE-CRYSTAL SILICON X-RAY ANALYZER

Silion x-ray analyzer crystals were microfabricated by dicing and etch ing 10.3 cm (4-inch) diam, 1.35 mm thick, undoped float zone (111) sil icon wafers. These analyzer crystals are intended for a beam line at t he Advanced Photon Source synchrotron accelerator ring under construct ion at the Argonne National Laboratory. Parallel and perpendicular, 1 mm spaced grooves were cut on the silicon wafers using an automated di cing saw. The grooves were cut at 15-degrees and 105-degrees to the [1 10] primary flat to avoid crystallographic cleavage directions because mechanical strength was desired. The depth of the grooves was 1.15 mm , which was 85% of the wafer thickness. The two cutting parameters, pr ogressive cutting thickness, and feed rate were optimized to reduce sa w damage and chipping. Saw damage, which extended over a region of abo ut 30 mum from grooves was removed by isotropic etching. The quality o f the single crystal was tested by measuring the width of x-rav rockin g curves with a double-crystal diffractometer. The best width obtained with 11.2 arc-s. Since the ideal full width at half maximum (FWHM) ac cording to x-rav dynamical diffraction theory is 9.7 arc-s, a broadeni ng function with a FWHM of only 5.6 arc-s is present due to residual s trains (quadrature addition is assumed).