We have fabricated the Au/n-InP Schottky barrier diodes (SBDs) with and without an intentionally grown interfacial oxide layer. The oxide layer on chemically cleaned indium phosphide (InP) surface has been obtained by exposure to water vapor at 1 ml/min at 200 degrees C before metal evaporation. The chemical composition of the surface oxides grown on the InP is investigated using x-ray photoelectron spectroscopy. Phosphorus is present as In(Po-3)(3), InPO4, P2O5 and elemental R The influence of the oxide on the Schottky barrier formation and contact stability at the InP (100) surface upon subsequent metal deposition has been investigated. The transport properties of the metal-semiconductor contacts have been observed to be significantly affected by the presence of the interfacial oxide layer. Thus, the barrier height has been increased by similar to 140 meV for the Au/n-InP SBD by means of the interfacial oxide grown by use of absorbed water vapor. Furthermore, in order to observe the effect of the aging in the Au/n-InP SBD with and without the interfacial oxide layer, the current-voltage (I-V) measurements have also been repeated 7, 14, 28, 45, 56, and 70 days after fabrication of these diodes. The obtained diode parameters were examined statistically and it was found that the reference and oxidized Au/n-InP SBDs exhibited stable characteristics 14 days after metal deposition. (c) 2005 American Vacuum Society.