Characterization of microstructures formed on MeV ion-irradiated silver films on Si(111) surfaces

Ag epitaxial layers on silicon single crystal surfaces, upon MeV Si ion irr adiation, undergo improvement in crystalline quality. This is often associa ted with remarkable changes in surface morphology. Growth of micron-sized ( 1-30 tm) islands has been observed on epitaxial Ag(I 1 1) thin films (simil ar to 100 nm), deposited on Br-passivated Si(I 1 1) surfaces, when irradiat ed with energetic Si ions (1-12 MeV). This shows ion beam-induced mass tran sport in the Ag layer. The islands on the surface of the Ag films show a va riation in height, diameter and number density as a function of ion energy as well as fluence. A detailed analysis with ion microprobe and atomic forc e microscopy is presented. Many islands interestingly appear to have a trip let pattern - the island, a depleted region around the island and a frozen wave packet. A tentative explanation for the formation of the triplet struc ture is given. (C) 2001 Elsevier Science B.V. All rights reserved.