[en] Nanometer sized Au clusters deposited on a silicon substrate forming Au-SiO₂-Si structure are important for the development of contacts in nanotechnology. Systematic x-ray reflectivity, scanning probe microscopy, and scanning tunneling spectroscopy measurements were done to understand the relationship between morphology and electrical transport properties of this nanostructural metal-insulator-semiconductor system. The presence of an interfacial layer at the metal-insulator interface dictates the tunneling current through this structure and exhibits a gap leading to a suppression of current. Local density of states and electron density/thickness of the interfacial layer have been extracted from the measurements to understand the evolution of metallicity of this Au-SiO₂-Si structure