The electrical behavior of Au/SiOx/n-GaAs Schottky structures has been studied using a statistical approach. II has been concluded that the obtained unusual electrical behavior is connected mainly with different Fermi-level pinning position and lateral microinhomogeneities of the barrier height induced by different average thickness of the SiOx interlayer along the wafer. The results of cross-sectional transmission electron microscopy and the temperature dependence of the electrical characteristics confirm this conclusion. (C) 1998 Elsevier Science Ltd. All rights reserved.