Molecular beam epitaxial growth of BaTiO3 single crystal on Ge-on-Si(001) substrates

Thin films of perovskite type BaTiO3 (BTO) oxide have been grown epitaxially directly on Ge(001) surface at high temperature using molecular beam epitaxy. A stable (2×1) BaGex surface periodicity is the critical enabling template for subsequent BTO heteroepitaxy on Ge(001). Reflection high energy electron diffraction (RHEED) and transmission electron microscopy indicate that high quality heteroepitaxy on Ge-on-Si(001) take place with ⟨100⟩BTO(001)∥⟨110⟩Ge(001) confirming a 45° rotation epitaxial relationship. X-ray diffraction has been used to study the BTO lattice parameters and we evidenced that both tetragonal and cubic phases of BTO are present in the epilayer.