Production of ordered silicon nanocrystals by low-energy ion sputtering

We report on the production of ordered assemblies of silicon nanostructures by means of irradiation of a Si (100) substrate with 1.2 keV Ar+ ions at n ormal incidence. Atomic force and high-resolution transmission electron mic roscopies show that the silicon structures are crystalline, display homogen eous height, and spontaneously arrange into short-range hexagonal ordering. Under prolonged irradiation (up to 16 h) all dot characteristics remain la rgely unchanged and a small corrugation develops at long wavelengths. We in terpret the formation of the dots as a result of an instability due to the sputtering yield dependence on the local surface curvature. (C) 2001 Americ an Institute of Physics.