Microstructure of β-FeSi2 thin films prepared by pulsed laser deposition

Tsuyoshi Yoshitake, Tatsuya Nagamoto, Kunihito Nagayama

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    Abstract

    Iron disilicide thin films were prepared by pulsed laser deposition (PLD) on Si (100) substrates using a FeSi2 alloy target. Droplet-free films could be deposited at a fluence between 2 and 4 J/cm2 using a 193-nm laser. Polycrystalline films of β-FeSi2 phase could be formed even at a substrate temperature of 20 °C. In addition to the β-FeSi2 phase, the FeSi phase was observed for substrate temperatures between 400 and 600 °C. This is attributed to the mobility enhancement of Si atoms. At 700 °C, the FeSi phase disappeared and β-FeSi2 single-phase films having a columnar structure were grown due to the mobility enhancement of both the Fe and Si atoms. At the substrate temperatures of less than 600 °C, the lattices of β-FeSi2 were distorted. At substrate temperatures higher than 700 °C, the lattice constants approached the bulk values. The films deposited at more than 700 °C were grown epitaxially on Si(100) with the relation of β-FeSi2 (041) or (014) ∥ Si (220) at the beginning of deposition. As the film thickness increases, the epitaxial growth becomes disordered and finally becomes non-oriented near the film surface. For all films deposited at various substrate temperatures, the stoichiometry was constant in the depth direction. Thus, it is suggested that Si atoms from the substrate hardly diffused into the film. The generation of iron disilicide in the PLD deposition mechanism is also discussed.

    Original languageEnglish
    Pages (from-to)236-243
    Number of pages8
    JournalThin Solid Films
    Volume381
    Issue number2
    DOIs
    Publication statusPublished - Jan 15 2001

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    All Science Journal Classification (ASJC) codes

    • Electronic, Optical and Magnetic Materials
    • Surfaces and Interfaces
    • Surfaces, Coatings and Films
    • Metals and Alloys
    • Materials Chemistry

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