Microscopic Compound Formation at the Pd-Si(111) Interface

Photoemission studies of Pd on clean Si(111) surfaces show that formation of the Pd₂Si compound dominates the microscopic chemistry and properties of the Pd-Si interface. No evidence is found for interface dipoles or occupied metal-induced interface states in this system. The Pd₂Si reaction product (a metal) has an electronic structure more like that of the noble metals than the transition metals, with an occupied $4d$ band located {~}2.75 eV below the Fermi energy.