Fermi-level depinning at the metal-germanium interface by the formation of epitaxial nickel digermanide NiGe2 using pulsed laser anneal

A reduced effective electron Schottky barrier height ΦBn,eff of 0.37 eV is obtained at the epitaxial-NiGe2/Ge(100) interface. This is substantially lower than an ΦBn,eff of 0.60 eV obtained at the NiGe/Ge(100) interface. The Fermi-level pinning effect, which is commonly observed between metals and Ge, is reduced at the NiGe2/Ge(100) interface. This is attributed to the formation of epitaxial NiGe2 on Ge(100), which is expected to have a lower density of interface states due to reduced number of dangling bonds.