Current-voltage characteristics of Schottky barriers with barrier heights larger than the semiconductor band gap:: The case of NiGe/n-(001)Ge contact -: art. no. 113706

Current-voltage-temperature characterization has been performed on NiGe/n-(100)Ge Schottky contacts that were formed by the solid-state reaction of Ni with Ge. An effective barrier height of 0.732-0.735 eV, which is larger than the band-gap 0.66 eV of Ge, was obtained. A physical model describing the current transport mechanism in a Schottky contact with a barrier height larger than the semiconductor band gap is proposed and discussed on the basis of thermionic-field emission as the dominant transport mechanism. The observation of a barrier height larger than the semiconductor band gap should be of technological importance as it suggests that NiGe is an ideal contact and Schottky source/drain material in Ge-based p-metal-oxide-semiconductor field-effect-transistors. (C) 2005 American Institute of Physics.