Si/SiO2 interface structures in laser-recrystallized Si on SiO2

Si/SiO2 interface structures in laser-recrystallized Si on SiO2 were studied with a high-resolution transmission electron microscope. The (001) Si/SiO2 interface with (001) Si substrate as a seed was excellent in flatness, flatter than that of the initial interface before recrystallization. However, the (11̄5) Si/SiO2 interface with (11̄5) Si substrate was saw-toothed with {100}T and {111}T microfacets. After twin boundary generation, the interface was changed to {110}T or {111}T and was flattened considerably. A Si/SiO2 interface reaction occurred during laser recrystallization. Since low-index Si planes are thought to have low interface energies with SiO2 at their interface, atomically flat or saw-toothed interfaces appeared as a result of this interface reaction. Moreover, twin boundaries, rather than saw-toothed interfaces, might have been generated for the reduction of the interface energy.