Improvement of Ag(1 1 1) epitaxy on Si(1 1 1) by mev si⁺ irradiation and ion microbeam analysis of thermally induced morphology

Epitaxial Ag(1 1 1) thin films (~125 nm) have been grown on Br-passivated Si(1 1 1) surfaces under high vacuum. Growth features observed from XRD, RBS/channeling and TEM/TED experiments are comparable to those grown under UHV conditions. RBS/channeling measurements on the Ag layer showed a minimum yield (&#967;<SUB>min</SUB>) of 62% indicating a poor crystalline quality. We irradiated the Ag(1 1 1) layer with 1 MeV Si<SUP>+</SUP> at fluences of 5&#215;10<SUP>15</SUP> and 1&#215;10<SUP>16 </SUP>ions/cm<SUP>2</SUP> with the substrate at room temperature and an ion current density of 50 nA/cm<SUP>2</SUP>. Following irradiation, the measured &#967;<SUB>min</SUB> 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&#176;C due to some grain boundary melting. In thermal annealing at &#8805;600&#176;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<SUP>+</SUP> ions