AVS 50th International Symposium
    High-k Gate Dielectrics and Devices Topical Conference Tuesday Sessions
       Session DI-TuA

Paper DI-TuA8
Medium Energy Ion Scattering Studies of the Structure and Composition of Epitaxial SrTiO@sub 3@ Films on Silicon

Tuesday, November 4, 2003, 4:20 pm, Room 317

Session: High-k Dielectric Characterization
Presenter: L.V. Goncharova, Rutgers University
Authors: L.V. Goncharova, Rutgers University
D.G. Starodub, Rutgers University
E.L. Garfunkel, Rutgers University
T. Gustafsson, Rutgers University
D.G. Schlom, Pennsylvania State University
Correspondent: Click to Email
Thin crystalline oxide films on silicon show a wide range of new electronic, optical, and magnetic properties with potential impact on novel devices. Precision control of the composition, stoichiometry and structure of such films and the ability to characterize the films and their interfaces are therefore of central importance. We have used high-resolution medium energy (~ 100 keV) ion scattering (MEIS) to investigate the composition and structure as a function of depth of thin (40-250 Å) crystalline SrTiO@sub 3@ films on Si (100). As ion beams are penetrating, and the ion-solid interaction is well understood, this technique allows us to get quantitative information both about the film/vacuum and about the film/substrate interface structure. Different channeling and blocking geometries have been utilized to distinguish epitaxial/amorphous regions, to characterize the chemical composition of the SrTiO@sub 3@/Si interface and also to give information about structural parameters. Thin SrTiO@sub 3@ films were grown epitaxially on Si(001) at the low temperatures in an excess of oxygen.@footnote 1@ Our MEIS results show that films grown by this method have A-site (SrO) termination. We further show that submonolayer amounts of strontium silicide, used in the initial stages of growth, are fully eliminated from the interface after growth is completed and that instead Ti has diffused into the interface region. The SrTiO@sub 3@/Si interface was confirmed to be crystalline; however the geometrical structure deviates significantly both from the 'bulk' epitaxial film and from the substrate. Possible structural models for the transition region and mechanisms of titanium incorporation in the interface region will be discussed. @FootnoteText@ @footnote 1@ J. Lettieri, J.H. Haeni, and D.G. Schlom, J.Vac.Sci.Technol. A 20 (2002) 1332.