TEM AND RAMAN-SCATTERING INVESTIGATION OF CARBON IN ANNEALED CO C SOFT-X-RAY MULTILAYERS/

The structures of the carbon sublayers in the annealed Co/C soft X-ray multilayers fabricated by using a dual-facing-target sputtering syste m have been characterized by transmission electron microscopy (TEM) an d Raman spectroscopy (RS). The results suggest that the structural var iations in the carbon layers can be roughly divided into three stages, i.e. ordering, crystalline and grain growth stages. At the ordering s tage with annealing temperatures below 400 degrees C, the amorphous ca rbon layers change from ones of bond-angle disorder and fourfold-bondi ng only to ones of threefold-bonding. At the crystalline stage, the am orphous carbon layers in the as-deposited multilayers crystallize to g raphite crystallites in the annealing temperature range of 500-600 deg rees C. At the grain growth stage, the specimens are annealed at tempe ratures higher than 700 degrees C. A growth in the graphite crystallit e dimensions is observed, which is consistent with the TEM results.