Experimental studies of the interface between hydrogen-terminated Si(111) and evaporated Au are reported. Anger Electron Spectroscopy (AES) and Scanning Tunneling Microscopy (STM)I in ambient conditions, were used to study the composition and electrical (I-V) properties of the Au/Si junction, as a function of Au film thickness. Au films of 5 nm present a rectifying behavior with the tunneling current for negative tip bias. This result is explained by the fact that Si is known to migrate through the Au layer. The I-V measurements point to the fact that enough Si segregates on top of the Au layer to form a reverse diode. It is also shown that the first monolayers of gold chemically bind to the silicon. Such a surface presents electrical metallic properties at this initial stage of gold growth on silicon.