We report a modification by thin silicon nitride intralayers of the Au/n-GaAs)(100) Schottky barrier height. Thin intralayers were obtained by nitridation of evaporated Si films on decapped GaAs substrates in an argon-nitrogen mixture plasma. The nitridation was performed at a beam energy <40 eV, with 573 K sample temperature. Gold was deposited to study in situ the Schottky barrier formation process with x-ray photoelectron spectroscopy. Internal photoemission spectroscopy and current-voltage measurements were used to evaluate the barrier modification on fully formed interfaces. Such a modification was analyzed in terms of theoretical calculations of the dipole created by the substrate-intralayer bonds. (C) 1997 American Institute of Physics.