Sputtering of Si with decaborane cluster ions

Decaborane cluster ions (B₁₀H_x⁺) may play an important role in the manufacturing of future MOS devices, as they facilitate a very shallow implantation of B with relatively high beam energy, which is partitioned among the constituent atoms. While the formation of B-doped shallow junctions in Si has been demonstrated, little is known about other effects of these complex ions on a solid. We have measured the sputtering yield of Si with decaborane cluster ions at 12 keV and demonstrated, by atomic force microscopy of the surface, that their impacts smooth rather than roughen the surface, similarly to much larger Ar cluster ions. This unexpected result has implications for the understanding of the mechanism of impacts of molecular and cluster ions.