Using in-situ scanning tunneling microscopy (STM) we have investigated the evolution of Si(111)-7×7 surfaces, prepared under ultrahigh vacuum condition, upon Ar⁺ion sputtering and subsequent annealing. We have monitored how the surface atomic arrangement changes upon annealing of the sputtered Si(111)-7×7 surface. Sputtering renders the Si(111)-7×7 surface amorphous and rough. Annealing at 500 C causes no recrystallization, although the surface roughness is reduced. When the sample is annealed at 600 C, recrystallization starts producing short-range orders. Flat-top nanoislands with a height distribution appear. The top surface of these nanoislands is ordered; most islands have Si(111)-7×7 surface reconstruction, while there are also islands with other surface reconstructions, such as 5×5, 2×2 etc. Smaller silicon nanodots grow at the edges of these flat-top islands.