Platinum/carbon multilayer reflectors for soft-x-ray optics

We have fabricated platinum/carbon (Pt/C) multilayer reflectors with 2d spacaings between 50 and 200 Å, using an electron-beam evaporator. We investigated the effects of 2d values, the number of layer pairs, substrate temperature, coatings, and the long-term stability on the reflectivity performance by using characteristic x rays and monochromatized synchrotron radiation in the 0.8-8-keV region. In this study we show that Pt/C multilayers with 10-20 layer pairs exhibit high and stable soft-x-ray reflectivity. The interfacial roughness was measured in the range of 5 Å and becomes lower for structures deposited at liquid-nitrogen temperatures. Coating these reflectors with a 100-Å-thick platinum layer increased the grazing angle reflectivity without significantly lowering the Bragg peak reflectivity.