Electron Induced X-Ray Emission Spectroscopy as a Method for Interface Study

It is shown that from X-ray emission spectroscopy induced by electrons having appropriate kinetic energy, it is possible to analyze the valence electron distribution of solid/solid interfaces with a resolution equal to a few Å. Ni 3d states are obtained for metal/metal (Ni/Al) and metal/insulator (Ni/MgF2 and Ni/SiO) interfaces. The structure of the interface, i.e. whether it is steep or diffuse can be determined. Chemical bonding between atoms in contact, when it exists, is evidenced. The method can be applied to systems such as they are encountered in fields like adhesion and microelectronics. The only limitation is that the element, which is studied in one of the materials in contact, must not be a constituent of the other material