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Optical Properties of Thin-film Uranium Oxide in the XUV. Shannon Lunt, David D. Allred, R. Steven Turley, Elke Jackson, Kristi Adamson, Richard Sandberg Department of Physics and Astronomy, Brigham Young University. Mirrors in the EUV. EUV: 50-1500nm (rough estimate) Difficulties:
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Optical Properties of Thin-film Uranium Oxide in the XUV Shannon Lunt, David D. Allred, R. Steven Turley, Elke Jackson, Kristi Adamson, Richard Sandberg Department of Physics and Astronomy, Brigham Young University
Mirrors in the EUV • EUV: 50-1500nm (rough estimate) • Difficulties: • Absorption of Materials • Need multilayers • High Vacuum • Applications: • XUV Lithography • Soft x-ray Microscopy • Astronomy Index of Refraction: ñ=n+ik
Why Study Uranium Oxide? • IMAGE project showed benefits of UO2: • High reflectivity. • Stability. • Oxidation rate of Uranium: rate=12.52*ln(t)-31 Å/sec or about 40 Å in 5 minutes.1 • Data on optical constants sparse. • Different sources disagree. 1Oliphant, David T. Characterization of Uranium, Uranium Oxide and Silicon Multilayer Thin Films, Masters Thesis, Brigham Young University, 2000.
Diagram of Films and Characterization • Roughness - AFM. • Thickness of Uranium Oxide layer - XRD and ellipsometry. • Thickness of SiO2 - ellipsometry before sputtering. • Composition – XPS.
Reflectivity Measurements • McPherson, Model 225, 1-meter scanning monochromator • 1200 lines/mm grating for 250Å to 1200Å • 600 lines/mm grating for 450Å to 1600Å. • Fit using IMD to calculate optical constants. Diagram of Monochromator
Future Work • Alignment and Focusing of the 1200 lines/mm grating. • Improve the reflectivity measurement system. • Measure the reflectivities of samples at wavelengths of interest. • Calculate optical constants.