STRUCTURAL STUDY OF AG OVERLAYERS DEPOSITED ON A SI(111) SUBSTRATE BY IMPACT-COLLISION ION-SCATTERING-SPECTROSCOPY WITH TIME-OF-FLIGHT DETECTION

Using the technique of time-of-flight mode impact-collision ion-scattering-spectroscopy, we have studied the structure of two kinds of Ag thin films deposited onto Si(111)7×7 substrates. We have shown that (1) the RT deposited Ag thin film of 10 ML thickness consists of type-A and type-B domains of Ag(111), with type-B being rotated 180° about the surface normal, (2) the experimental ICISS angle scans for the Si(111)√3×√3R30°-Ag surface cannot be explained by the embedded-Ag model proposed so far, (3) the Ag honeycomb structure residing on top of Si is unlikely for the √3 × √3-Ag surface, and (4) both the Ag-trimer and the HCT model, residing on top of Si are more likely, though a clear preference between these two models has not been obtained as yet. © 1989.