In situ X-ray multilayer reflectometry based on the energy dispersive method

We demonstrate the capacities of the energy dispersive method (EDM) by measuring in situ and during deposition the reflectivity of 5 and 9.2 nm period Mo/Si multilayers in the 5 to 40 keV energy range. The required X-ray continuum spectrum was emitted by an X-ray tube with an Ag anode and the reflected spectra were analyzed in energy by a Si(Li) detector. Kapton windows allow the source and the detector to be set outside the deposition chamber. The absolute intensity and FWHM of several Bragg peaks orders are measured after deposition of successive periods. The EDM method is compared with two others established in situ angular dispersive methods (ADM).