A technique to form metallic nanodots in a two-step process involving: (1) reacting a silicon-containing gas precursor (101) (e.g., silane) to form silicon nuclei (117) over a dielectric film layer (103B); and (2) using a metal precursor to form metal nanodots where the metal nanodots use the silicon nuclei (117) from step (1) as nucleation points. Thus, the original silicon nuclei (117) are a core material for a later metallic encapsulation step. Metallic nanodots have applications in devices such as flash memory transistors.