Poly-Si films 200–600 nm thick deposited on (100) Si substrates having SiO2 stripe patterns have been transformed by Q-switched pulse ruby laser irradiation with energy densities between 1.0 and 2.0 J/cm2 into single crystals on the SiO2 patterns as well as on the Si. The regrowth of poly-Si on SiO2 starts laterally from regrown poly-Si on Si just after or during the vertical growth of poly-Si on Si by liquid phase epitaxy. Such lateral growth of poly-Si on SiO2 makes single crystal Si film formation possible on entire SiO2 patterns up to 4 µm wide under appropriate laser power and poly-Si thickness conditions. However, straight stacking faults in the direction remain in Si films grown on SiO2, although dislocations generated in the Si regrown on Si escape to the sample surface along the inclined plane of the SiO2 window edges.