Measuring the electronic structure of disordered overlayers by electron momentum spectroscopy: The Cu/Si interface

The Cu-Si interface was studied by electron momentum spectroscopy. A thick disordered interface is formed if one material is deposited on the other. Electron momentum spectroscopy measures intensity as a function of binding energy and target electron momentum. Momentum resolution is demonstrated to be very helpful in interpreting the data, even for these disordered interfaces. The interface layer has a well-defined electronic structure, different from either Si or Cu, and consistent with silicide formation. Information is obtained about the total bandwidth of the interface compound, effective Brillouin zone size and Fermi radius. No clear differences are observed in the electronic structure of the interface layer for Si deposited on Cu or Cu deposited on Si.