Different Ag/Si(111) systems have been examined using synchrotron x-ray diffraction. Multi-atomic-layer deposition of Ag onto a Si(111)-(7×7) surface maintained at room temperature results in an unstrained, (111)-oriented film. The interface shows a Ag-modified (7×7) structure which when annealed above 200-250°C transforms to a (1×1) structure. Although this is near the characteristic temperature for formation of the (3 × 3) R30° surface reconstruction commonly observed for a monolayer of Ag adsorbed on Si(111), no evidence of this (3 × 3) R30° reconstruction was found at the interface. A Ag monolayer (3 × 3) R30° surface, further covered by multilayer Ag deposition at room temperature, also shows no indication of the (3 × 3) R30° reconstruction at the interface. This indicates that the actual interface structure may or may not be related to the clean or adsorbed layer structures. The structure of the Ag-Si interface was further characterized by scans of the crystal truncation rods. Both the (7×7) interface prepared by room-temperature deposition and the annealed (1×1) interface show fairly sharp boundaries. The results suggest some intermixing occurs at the monolayer level for the annealed interface. The structure of the Ag film was also investigated. © 1995 The American Physical Society.