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Thin-film and multilayer deposition and characterizationA large part of the activity of the Photon Physics Group consists of research into the characteristics of thin films and multilayers, especially their use as optical elements in the extreme ultraviolet (EUV). We maintain a number of systems for the characterization of thin films and multilayers including the NIST/DARPA EUV Reflectometry Facility and the in-situ optical constants measurement facility. For structural characterization of films and multilayers, we use grazing incidence x-ray diffraction, which allows us to determine thicknesses of layers and diffusion boundaries and surface roughnesses.
Figure 1. The electron-beam evaporation multilayer deposition system. We have a number of systems for thin-film fabrication. A thermal evaporation system is used primarily to fabricate thin-film photocathodes for the Nanodetector x-ray conversion microscope. A second is an ion-beam sputtering system currently under development. The primary system, however, is an electron-beam evaporator shown in the Figure 1. Layer thicknesses are monitored both by a crystal oscillator and by measuring the EUV reflectivity using a line source. Layers can also be ion polished using a noble-gas ion beam. Using this system we have made Co-C films with 9 % normal-incidence reflectivity at 6.35 nm. In test runs for the optics of the Schwarzschild Microscope we have obtained reflectivities of over 50% at 14 nm. For more information contact Charles Tarrio. Online: May 1998 |