Correlation between irradiated Cu²⁺ ion agglomeration and self-organized microdot formation on silicon surfaces

Micro-patterns have been formed as self-organized structures through Cu²⁺ ion beam irradiation at energy of 2.5 MeV and fluence of 3.4 × 10¹⁷ ion cm^-2 on the surface of a silicon wafer (111) of 0.5 mm thickness. The structure of dots has hexagonal shape with average size of 2.3 μm. The dots can be found aligned in arbitrary direction or arranged in a circular shape around bigger dot of 2.5 to 3.3 μm size. The distribution analysis of the Cu²⁺ ions on the silicon substrate surface was conducted using Energy Dispersive X-ray Spectroscopy (EDX) in conjunction with scanning electron microscopy (SEM) imaging of the obtained structures. It was observed that the irradiated ions migrate and accumulate in accordance with surface topographic features. This analysis provides new insights into the dynamic formation process of self-organized structures, highlighting the agglomeration of irradiated Cu²⁺ ions and indicating a clear link between ion distribution and pattern formation.