Electron interferometry at a metal-semiconductor interface

The tunneling microscope is used to excite electron standing waves at the ${\mathrm{NiSi}}_2$Si(111) metal-semiconductor interface. Conductivity mappings show contrast between type-A and type-B domains of nickel disilicide, as well as contrast between domains of type-B disilicide of varying thicknesses. We demonstrate the presence of buried steps, and that these steps can act as diffusion barriers in the reaction that leads to the formation of the nickel disilicide overlayer.