Intrinsic interface states and defect states for Si/NiSi₂(111)

The intrinsic interface states and the states associated with interfacial vacancies have been calculated for the type A Si/NiSi₂(111) interface. A prominent band of intrinsic interface states is predicted near and below the Si valence band maximum, E_v, dispersing downward from an energy in the Si band gap to an energy about 1 eV below E_v. This band should be observable in photoemission experiments. Our calculation for the interfacial Si vacancy on the NiSi₂ side of the interface yields a level, a few tenths of an electron volt above the valence band edge, that can explain observed Schottky barriers at Si/NiSi₂(111) interfaces.