Roles of Buffer Layers in Epitaxial Growth of SrTiO3 Films on Silicon Substrates

Heteroepitaxial growth of SrTiO3 (STO) films with and without buffer layers on Si(100) and (111) substrates has been conducted by a focused electron beam evaporation method. It has been found that thin metallic layers such as Ti and Sr are effective for improving the quality of overgrown STO films, which is probably due to the fact that the metallic layers deoxidize the surface SiO2 layers on Si substrates. It has also been found that a Sr buffer layer is effective for obtaining fairly good epitaxial films on both Si(100) and (111) substrates, while a Ti buffer layer is effective for obtaining good electrical properties of the film and interface.