The formation mechanism of Si nanocrystals in SiO2

Si nanocrystals (Si nc) were formed by the implantation of Si+ into a SiO2 film followed by high-temperature annealing. The microstructural evolution of Si nc with annealing time has been investigated by high-resolution transmission electron microscopy (HRTEM) in detail. Three evident growth phases have been observed: formation of amorphous Si-rich SiOx nodules; transformation of the amorphous nodules into Si nc and coalescence of small particles into larger ones. Based on the HRTEM results, a formation mechanism has been proposed for the Si nc embedded in SiO2.