Improvement of Ag(111) epitaxy on Si(111) by MeV Si+ irradiation and ion microbeam analysis of thermally induced morphology

Epitaxial Ag(1 1 1) thin films (similar to 125 nm) have been grown on Br-passivated Si(1 1 1) surfaces under high vacuum. Growth features observed from XRD, RES/channeling and TEM/TED experiments are comparable to those grown under UHV conditions. RBS/channeling measurements on the Ag layer showed a minimum yield (chi(min)) of 62% indicating a poor crystalline quality. We irradiated the Ag(1 1 1) layer with 1 MeV Si+ at fluences of 5 x 10(15) and 1 x 10(16) ions/cm(2) with the substrate at room temperature and an ion current density of 50 nA/cm(2). Following irradiation, the measured chi(min) values are 40% and 38%, respectively, indicating an improvement in crystalline quality of the Ag layer. This behaviour is also seen in thermal annealing upto 500 degrees C due to some grain boundary melting. In thermal annealing at greater than or equal to 600 degrees C desorption of Ag occurs leaving holes in the Ag layer. Morphology of the annealed layer has been analyzed with RBS/PIXE studies with an ion microbeam of He+ ions. (C) 1999 Elsevier Science B.V. All rights reserved.