Hard x-ray emission spectroscopy (XES) has been used to study buried layers and interfaces in a Fe/Si periodic multilayer. Until now, buried layers could be studied using the XES in the soft x-ray range. Here, we extend the methodology to study the buried interfaces in hard x-ray region (photon energy ≥ 5 keV). We report the formation of FeSi 2 at all the interfaces with thicknesses of 1.4 nm. X-ray reflectivity measurements enable us to deduce the structure and thickness of the multilayer stack, thereby confirming the presence of FeSi 2 .