Thermal properties of TiO2 films grown by atomic layer deposition

M. R. Saleem*, P. Silfsten, S. Honkanen, J. Turunen

*Corresponding author for this work

    Research output: Contribution to journalArticleScientificpeer-review

    29 Citations (Scopus)

    Abstract

    We study the thermal properties of amorphous TiO 2 thin films of various thicknesses t, grown by atomic layer deposition. The thermo-optic coefficient dn/dT and the temperature coefficient dρ/dT of film density ρ are determined from ellipsometric data in wavelength range 380 < λ < 1800 nm with the Cauchy model and the Lorentz-Lorenz relation. It is found that dn/dT exhibits negative values for films with t < 150 nm and positive values for thicker films, while no significant changes in the two coefficients take place if t < 200 nm. A qualitative physical explanation based on porosity of the thin films is suggested. Films with t = 60 nm are illustrated in detail at λ = 640 nm: the room-temperature values of the coefficients are found to be dn/dT = - 3.1 × 10 - 5°C - 1 and dρ/dT = - 4.8 × 10 - 5g cm - 3°C - 1.

    Original languageEnglish
    Pages (from-to)5442-5446
    Number of pages5
    JournalThin Solid Films
    Volume520
    Issue number16
    DOIs
    Publication statusPublished - 1 Jun 2012
    MoE publication typeA1 Journal article-refereed

    Keywords

    • Atomic layer deposition
    • Thermo-optic coefficient
    • Titanium oxide
    • Thin films
    • Optical materials
    • MODE RESONANCE FILTERS
    • TITANIUM-DIOXIDE
    • DENSITY

    Cite this