Solid phase regrowth of Si on sapphire has been investigated in the Si (amorphous)/Al (poly)/Al2O3(crystal) system. Using transmission electron microscopy, scanning electron microscopy, Auger electron spectroscopy, and Hall‐effect measurements, it has been shown that Si is transported through an Al film at 550 °C to producep‐type Si films on the sapphire substrate. The growth process has been shown to be initiated at Si nucleation sites on the substrate. These sites expand by mass accretion, forming island structures that coalesce to yield continuous large grained polycrystalline Si films on the sapphire surface.