Irradiation characteristics of metal-cluster-complex ions containing diverse multi-elements with large mass differences

Tetrairidium dodecacarbonyl, Ir-4(CO)(12), is a metal cluster complex which has a molecular weight of 1104.9. Using a metal-clustercomplex ion source, the interaction between Ir-4(CO)(n)(+) ions (n = 0-12) and silicon substrates was studied at a beam energy ranging from 2 keV to 10 keV at normal incidence. By adjusting Wien-filter voltage, the influence of CO ligands was investigated. Experimental results showed that sputtering yield of silicon bombarded with Ir-4(CO)(n)(+) ions at 10 keV decreased with the number of CO ligands. In the case of 2 keV, deposition tended to be suppressed by removing CO ligands from the impinging cluster ions. The influence of CO ligands was explained by considering changes in surface properties caused by the irradiation of Ir-4(CO)(n)(+) ions. It was also found that the bombardment with Ir-4(CO)(n)(+) ions at 2.5 keV caused deposition on silicon target. (c) 2007 Elsevier B.V. All rights reserved.