AVS 52nd International Symposium
    Thin Films Wednesday Sessions
       Session TF-WeA

Paper TF-WeA7
Strontium Oxide Template Monolayers by Surface Reactions of Metal-Organic Precursors with Si(100)

Wednesday, November 2, 2005, 4:00 pm, Room 306

Session: Fundamentals of Thin Films
Presenter: A.C. Cuadra, University of Delaware
Authors: A.C. Cuadra, University of Delaware
D. Skliar, University of Delaware
B.G. Willis, University of Delaware
Correspondent: Click to Email
The crystalline structure of strontium titanate (SrTiO@sub3@) consists of alternating 'sublayers' of SrO and TiO@sub 2@. Investigations by molecular beam epitaxy using elemental sources have shown that the heteroepitaxy of SrTiO@sub 3@ on Si(100) 2x1 surfaces can be nucleated with the SrO/Si(100) interface.@footnote 1@ This talk presents the experimental approach for monolayer growth of a SrO 'template' on a Si(100) 2x1 surface using strontium dipivaloylmethanate [Sr(dpm)@sub 2@] and water precursors as the sources of Sr and oxygen, respectively. To nucleate SrO on Si(100), the surface chemistry of the substrate must be tuned to direct the surface reactions of the strontium metal-organic precursor. Following native oxide desorption, dissociative chemisorption of H@sub 2@O is carried out in UHV to hydroxyl terminate Si(100) and initiate two-dimensional nucleation of the metal oxide while avoiding incubation periods common to the atomic layer deposition (ALD) of metal oxides. Metal oxide growth has been correlated to the concentration of hydroxyl groups on the substrate surfaces because they facilitate ligand exchange from the surface.@footnote 2@ Results show that thick SrO films with low carbon contamination can be grown on Si(100) and SiO@sub 2@ terminated with hydroxyl groups through wet chemical methods; this talk focuses on the initial SrO nucleation layer. In situ Auger electron spectroscopy (AES), low energy electron diffraction (LEED), and reflection high energy electron diffraction (RHEED) are used to investigate the crystalline quality of the nucleation monolayers and to verify the epitaxial orientation of SrO films on Si(100) 2x1 surfaces. @FootnoteText@ @footnote 1@ G.Y. Yang, et al., Journal of Material Research, 17 (1), 204-213 (2002)@footnote 2@ R.L. Puurunen, Applied Surface Science, 245, 6-10 (2005).