Residual stress in SiO2 thin films on silicon

Oili Ylivaara (Corresponding author), Matti Putkonen, Kristin Pfeiffer, Adriana Szeghalmi, Riikka Puurunen

    Research output: Chapter in Book/Report/Conference proceedingConference abstract in proceedingsScientific

    Abstract

    Silicon dioxide is common low-refractive index material used for example in optical interference coatings, in active devices as dielectrics or in microelectromechanical systems (MEMS) as sacrificial layers [1]. Depending on device and substrate limitations different process temperatures for film formation are encountered. In addition, required film thicknesses can vary from sub-nanometer to micrometer range thus limiting the applicable deposition methods. The residual stress of conventional silicon dioxide films deposited using thermal and chemical vapour deposition (CVD) has been widely studied, but only a scattered information about the residual stress in silicon dioxide films made by atomic layer deposition (ALD) is available [1, 2]. In this study a matrix of silicon dioxides grown onto 150 mm silicon wafers using thermal oxidation, low-pressure (LP) CVD, plasmaenhanced (PE) CVD and ALD was investigated for residual stress. Thermal oxide was grown from O2. LPCVD TEOS, low temperature oxide (LTO) and PECVD oxide were deposited using tetraethylorthosilicate, O2/SiH4 and N2O/SiH4 as precursors, respectively. ALD SiO2 was grown using AP-LTO-330 as a precursor. The process temperatures varied from 200 to 1050 °C depending on deposition method. For all oxides targeted film thickness was 100 nm. Wafer curvature measurement was used to determine the stress and its stability. Supporting information on thickness was obtained for the same samples by spectroscopic reflectometry. Residual stress varied from tensile to compressive depending on the deposition method. Large differences in stress stability were found for different deposition methods.
    Original languageEnglish
    Title of host publicationStress Evolution in Thin Films and Coatings Book of Abstracts
    PublisherAmerican Vacuum Society AVS
    Publication statusPublished - 2016
    EventStress Evolution in Thin Films and Coatings: from Fundamental Understanding to Control: Joint ICMCTF-SVC Workshop - Chicago, United States
    Duration: 2 Oct 20165 Oct 2016

    Workshop

    WorkshopStress Evolution in Thin Films and Coatings: from Fundamental Understanding to Control
    CountryUnited States
    CityChicago
    Period2/10/165/10/16

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    Keywords

    • ALD
    • SiO2
    • residual stress

    Cite this

    Ylivaara, O., Putkonen, M., Pfeiffer, K., Szeghalmi, A., & Puurunen, R. (2016). Residual stress in SiO2 thin films on silicon. In Stress Evolution in Thin Films and Coatings Book of Abstracts [17] American Vacuum Society AVS. http://www2.avs.org/conferences/STRESS16/pdfs/abstractbook.pdf