Comparison of interfaces for (Ba,Sr)TiO3 films deposited on Si and SiO2/Si substrates

Alexandra Suvorova, C.M. Lopez, E.A. Irene, Martin Saunders

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7 Citations (Scopus)


(Ba,Sr)TiO3(BST) thin films were deposited by ion sputtering on both bare and oxidized Si. Spectroscopic ellipsometry results have shown that a SiO2 underlayer of nearly the same thickness (2.6 nm in average) is found at the Si interface for BST sputter depositions onto nominally bare Si, 1 nm SiO2 on Si or 3.5 nm SiO2 on Si. This result was confirmed by high-resolution electron microscopy analysis of the films, and it is believed to be due to simultaneous subcutaneous oxidation of Si and reaction of the BST layer with SiO2. Using the conductance method, capacitance-voltage measurements show a decrease in the interface trap density D-it of an order of magnitude for oxidized Si substrates with a thicker SiO2 underlayer. Further reduction of D-it was achieved for the capacitors grown on oxidized Si and annealed in forming gas after metallization. (C) 2004 American Institute of Physics.
Original languageEnglish
Pages (from-to)2672-2675
JournalJournal of Applied Physics
Issue number5
Publication statusPublished - 2004


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