Epitaxial Growth of Si(111)/Er₂O₃ (111) Structure on Si(111) by Molecular Beam Epitaxy

The Si overlayers are grown by molecular beam epitaxy on atomically smooth Er₂O₃(111) films prepared on Si(111) substrates. Single crystalline Si overlayers are achieved and are evident due to the spot-like reflective high energy electron diffraction (RHEED) patterns and x-ray diffraction patterns. The epitaxial relationship of the Si overlayer along the surface with respect to the orientation of Er₂O₃ and the Si substrate is as follows: overgrown Si(111)//Er₂O₃(111)//Si(111). The rough surface of Si overlayers, as identified by both RHEED patterns and atomic force microscopy images, indicates a three-dimensional growth mode. The reason for this is based on the interfacial energy argument. Further growth of Er₂O₃ films on this rough Si overlayer leads to the polycrystalline nature of the topmost Er₂O₃ layer.