Lateral epitaxy by seeded solidification for growth of single-crystal Si films on insulators

Abstract

By using a new method, which we have named the LESS technique (lateral epitaxy by seeded solidification), single-crystal Si films have been grown over insulating layers on single-crystal Si substrates. An amorphous or polycrystalline Si film is deposited on the insulating layer, in which narrow stripes have been opened to expose the substrate. By using two carbon strip heaters, one of which is movable, the Si film is melted and frozen in such a manner that solidification begins within the stripe openings, where it is seeded by the substrate. The resulting single-crystal regions in turn seed lateral single-crystal growth over the adjacent insulating layer. Continuous single-crystal Si films have been obtained over SiO2 layers with openings spaced 50 or 500 mm apart, and single-crystal growth extending as far as 4 mm over Si3N4 has been observed.