Pustaka Ilmiah Universitas Padjadjaran

Abstrak

Glancing Ion Incidence On Si(100): Influence Of Surface Reconstruction On Ion Subsurface Channeling

We demonstrate that a Si target may exhibit the phenomenon of subsurface channeling for glancing incidence ions. To this end, we perform molecular-dynamics simulations of 3 keV Ar ion impact at grazing incidence(83 o toward the surface normal) on a Si (100) surface. Both an unreconstructed and a (2 × 1) dimer-reconstructed surface are investigated. In both cases, the ion is re?ected from the ?at terrace and creates neither damage nor sputtering. The situation changes when a surface step is introduced on the surface; ion incidence in the vicinity of the step induces both damage and sputtering. We find that the phenomenon of subsurface channeling plays a dominant role in damage creation at the step edge. Subsurface channels aligned in the #110$ direction are created under the reconstructed surface; they run parallel to the dimer rows. If the ion incidence geometry is favorable—incidence azimuth aligned along #110$ and the ion approaching an unbonded B step—the ion can enter these channels. Without surface reconstruction no subsurface channeling can occur. Subsurface-channeled ions generate peculiar surface damage patterns which may allow their identi?cation in experiment.