Beam-Induced Nanoscale Ripple Formation On Silicon With The Metal-Cluster-Complex Ion Of Ir-4(Co)(7)(+)

The surface topography of Si(100) bombarded with 2.5-10 keV Ir-4(CO)(7)(+) at an incident angle of 45 degrees was investigated by atomic force microscopy. Experimental results showed that self-organized ripple structures with a wavelength below 30 nm were produced at a beam energy of 5 keV. It was found that the wavelength of the ripples increased with decreasing beam energy. which is different from results obtained using conventional ion beams. In addition, surface roughness proved to increase with decreasing beam energy. The phenomena were explained by considering a substantial decrease in sputtering yield and the subsequent compositional change in the target at lower-beam-energy Ir-4(CO)(7)(+) bombardment. Furthermore, the surface roughness was also confirmed to increase with increasing oxygen partial pressure.