Heteroepitaxy of perovskite ferroelectrics on silicon: a path to silicon-integrated ferroelectrics

摘要

We have studied the thin-film heteroepitaxy between simple perovskite oxides and Si as it is accomplished with molecular beam epitaxy growth. Interface chemistry and electrostatics play critical roles in determining whether a commensurate interface develops. Submonolayer silicides are the required precursors for the transition to commensurate epitaxial oxide structures in these systems. This approach is illustrated with BaTiO(sub 3); high crystalline perfection is achieved and resistivities as high as 10(sup 13) ohm-cm can be developed for BaTiO(sub 3) MOS capacitors on (001) Si. The epitaxy is (100)BaTiO(sub 3)//(001)Si with (0001)BaTiO(sub 3) aligned in plane with the polar axis along the (110) of Si. This epitaxy is dominated by a strong propensity for Ba to order along the (110) of Si during the submonolayer silicide formation. This commensurate heteroepitaxial growth leads to a truly monolithic crystal and attendant properties. 9 figs, 23 refs.