Au(evaporated film) ‐semiconductor(substrate) systems were studied by Auger electron spectroscopy. For semiconductors with energy gaps (Eg) smaller than ∼2.5 eV, even at room temperature a considerable fraction of atoms constituting the semiconductors were found to accumulate on the surfaces of Au films, indicating ready interfacial interaction between these materials. Study of the interface regions of the above systems verified the occurrence of the room‐temperature interfacial reactions.