ALD Al2O3 from TMA and water on Si: residual stress, elastic modulus, hardness and adhesion: residual stress, elastic modulus, hardness and adhesion

Oili Ylivaara (Corresponding author), Xuwen Liu, Lauri Kilpi, Jussi Lyytinen, Dieter Schneider, Mikko Laitinen, Jaakko Julin, Saima Ali, Sakari Sintonen, Maria Berdova, Eero Haimi, Timo Sajavaara, Helena Ronkainen, Harri Lipsanen, Jari Koskinen, Simo-Pekka Hannula, Riikka L. Puurunen

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

    Abstract

    Use of atomic layer deposition (ALD) in microelectromechanical systems (MEMS) has increased as ALD enables conformal growth on 3-dimensional structures at relatively low temperatures. For MEMS device design and fabrication, understanding of the residual stress and mechanical properties of thin film is crucial as these influence directly the device properties and performance. Al2O3 from Me3Al and H2O is one of the most often used materials, but even for that, a detailed study of the mechanical properties as a function of ALD temperature is missing. In this work a comprehensive study of the stress, elastic modulus, hardness and adhesion of atomic layer deposited (ALD) Al2O3 films grown at 110 - 300 °C from trimethylaluminum and deionized water is presented. Film stress was analysed by wafer curvature measurements and Stoney's equation, elastic modulus by nanoindentation and surface-acoustic wave measurements, hardness by nanoindentation, and adhesion by microscratch testing and scanning nanowear measurements. The films were also analysed by ellipsometry, optical reflectometry, x-ray refl ectivity and time-of-flight elastic recoil detection for refractive index, thickness, density and impurities. The ALD Al2O3 films were under tensile stress, in the scale of hundreds of MPa. The magnitude of the residual stress decreased strongly with increasing ALD temperature. Growth-induced stress accounted for most of the stress at low ALD temperature and its importance decreased with increasing ALD temperature. The stress was independent of the type of ALD reactor used. Films grown at 150 to 300 °C had a fairly constant elastic modulus about 170 GPa and hardness of 10-11 GPa. Films grown at 110 °C were softer with a lower elastic modulus, which can at least partly explained by the higher residual hydrogen content in the films. ALD Al2O3 films adhered strongly on RCA-cleaned silicon with SiOx termination. The large set of data obtained in this work as a function of ALD temperature allowed a more detailed observation of the trends in the measured properties than has been possible before. For example, a continuously increasing elastic modulus as a function of ALD temperature was not observed in this study. Instead, after initial increase at low temperature elastic modulus settled to approximately constant value at 150 °C.
    Original languageEnglish
    Title of host publicationTechnical Program & Abstracts, published abstract of a poster
    PublisherAmerican Vacuum Society AVS
    Publication statusPublished - 2013
    Event13th International Conference on Atomic Layer Deposition, ALD 2013 - San Diego, California, San Diego, United States
    Duration: 28 Jul 201331 Jul 2013
    Conference number: 13

    Conference

    Conference13th International Conference on Atomic Layer Deposition, ALD 2013
    Abbreviated titleALD 2013
    CountryUnited States
    CitySan Diego
    Period28/07/1331/07/13

    Fingerprint

    atomic layer epitaxy
    residual stress
    modulus of elasticity
    adhesion
    hardness
    water
    nanoindentation
    microelectromechanical systems
    temperature
    mechanical properties
    tensile stress
    ellipsometry
    reactors
    curvature
    wafers
    refractivity
    trends
    impurities
    fabrication
    scanning

    Keywords

    • ALD
    • Atomic Layer Deposition
    • Al2O3

    Cite this

    Ylivaara, O., Liu, X., Kilpi, L., Lyytinen, J., Schneider, D., Laitinen, M., ... Puurunen, R. L. (2013). ALD Al2O3 from TMA and water on Si: residual stress, elastic modulus, hardness and adhesion: residual stress, elastic modulus, hardness and adhesion. In Technical Program & Abstracts, published abstract of a poster American Vacuum Society AVS.
    Ylivaara, Oili ; Liu, Xuwen ; Kilpi, Lauri ; Lyytinen, Jussi ; Schneider, Dieter ; Laitinen, Mikko ; Julin, Jaakko ; Ali, Saima ; Sintonen, Sakari ; Berdova, Maria ; Haimi, Eero ; Sajavaara, Timo ; Ronkainen, Helena ; Lipsanen, Harri ; Koskinen, Jari ; Hannula, Simo-Pekka ; Puurunen, Riikka L. / ALD Al2O3 from TMA and water on Si: residual stress, elastic modulus, hardness and adhesion : residual stress, elastic modulus, hardness and adhesion. Technical Program & Abstracts, published abstract of a poster. American Vacuum Society AVS, 2013.
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    title = "ALD Al2O3 from TMA and water on Si: residual stress, elastic modulus, hardness and adhesion: residual stress, elastic modulus, hardness and adhesion",
    abstract = "Use of atomic layer deposition (ALD) in microelectromechanical systems (MEMS) has increased as ALD enables conformal growth on 3-dimensional structures at relatively low temperatures. For MEMS device design and fabrication, understanding of the residual stress and mechanical properties of thin film is crucial as these influence directly the device properties and performance. Al2O3 from Me3Al and H2O is one of the most often used materials, but even for that, a detailed study of the mechanical properties as a function of ALD temperature is missing. In this work a comprehensive study of the stress, elastic modulus, hardness and adhesion of atomic layer deposited (ALD) Al2O3 films grown at 110 - 300 °C from trimethylaluminum and deionized water is presented. Film stress was analysed by wafer curvature measurements and Stoney's equation, elastic modulus by nanoindentation and surface-acoustic wave measurements, hardness by nanoindentation, and adhesion by microscratch testing and scanning nanowear measurements. The films were also analysed by ellipsometry, optical reflectometry, x-ray refl ectivity and time-of-flight elastic recoil detection for refractive index, thickness, density and impurities. The ALD Al2O3 films were under tensile stress, in the scale of hundreds of MPa. The magnitude of the residual stress decreased strongly with increasing ALD temperature. Growth-induced stress accounted for most of the stress at low ALD temperature and its importance decreased with increasing ALD temperature. The stress was independent of the type of ALD reactor used. Films grown at 150 to 300 °C had a fairly constant elastic modulus about 170 GPa and hardness of 10-11 GPa. Films grown at 110 °C were softer with a lower elastic modulus, which can at least partly explained by the higher residual hydrogen content in the films. ALD Al2O3 films adhered strongly on RCA-cleaned silicon with SiOx termination. The large set of data obtained in this work as a function of ALD temperature allowed a more detailed observation of the trends in the measured properties than has been possible before. For example, a continuously increasing elastic modulus as a function of ALD temperature was not observed in this study. Instead, after initial increase at low temperature elastic modulus settled to approximately constant value at 150 °C.",
    keywords = "ALD, Atomic Layer Deposition, Al2O3",
    author = "Oili Ylivaara and Xuwen Liu and Lauri Kilpi and Jussi Lyytinen and Dieter Schneider and Mikko Laitinen and Jaakko Julin and Saima Ali and Sakari Sintonen and Maria Berdova and Eero Haimi and Timo Sajavaara and Helena Ronkainen and Harri Lipsanen and Jari Koskinen and Simo-Pekka Hannula and Puurunen, {Riikka L.}",
    note = "CO:K University of Jyv{\"a}skyl{\"a}, Finland CO:Aalto University CO:U Fraunhofer IWS Dresden CA2: TK203 CA2: TK610 SDA: MEL Project code: 74717",
    year = "2013",
    language = "English",
    booktitle = "Technical Program & Abstracts, published abstract of a poster",
    publisher = "American Vacuum Society AVS",
    address = "United States",

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    Ylivaara, O, Liu, X, Kilpi, L, Lyytinen, J, Schneider, D, Laitinen, M, Julin, J, Ali, S, Sintonen, S, Berdova, M, Haimi, E, Sajavaara, T, Ronkainen, H, Lipsanen, H, Koskinen, J, Hannula, S-P & Puurunen, RL 2013, ALD Al2O3 from TMA and water on Si: residual stress, elastic modulus, hardness and adhesion: residual stress, elastic modulus, hardness and adhesion. in Technical Program & Abstracts, published abstract of a poster. American Vacuum Society AVS, 13th International Conference on Atomic Layer Deposition, ALD 2013, San Diego, United States, 28/07/13.

    ALD Al2O3 from TMA and water on Si: residual stress, elastic modulus, hardness and adhesion : residual stress, elastic modulus, hardness and adhesion. / Ylivaara, Oili (Corresponding author); Liu, Xuwen; Kilpi, Lauri; Lyytinen, Jussi; Schneider, Dieter; Laitinen, Mikko; Julin, Jaakko; Ali, Saima; Sintonen, Sakari; Berdova, Maria; Haimi, Eero; Sajavaara, Timo; Ronkainen, Helena; Lipsanen, Harri; Koskinen, Jari; Hannula, Simo-Pekka; Puurunen, Riikka L.

    Technical Program & Abstracts, published abstract of a poster. American Vacuum Society AVS, 2013.

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

    TY - CHAP

    T1 - ALD Al2O3 from TMA and water on Si: residual stress, elastic modulus, hardness and adhesion

    T2 - residual stress, elastic modulus, hardness and adhesion

    AU - Ylivaara, Oili

    AU - Liu, Xuwen

    AU - Kilpi, Lauri

    AU - Lyytinen, Jussi

    AU - Schneider, Dieter

    AU - Laitinen, Mikko

    AU - Julin, Jaakko

    AU - Ali, Saima

    AU - Sintonen, Sakari

    AU - Berdova, Maria

    AU - Haimi, Eero

    AU - Sajavaara, Timo

    AU - Ronkainen, Helena

    AU - Lipsanen, Harri

    AU - Koskinen, Jari

    AU - Hannula, Simo-Pekka

    AU - Puurunen, Riikka L.

    N1 - CO:K University of Jyväskylä, Finland CO:Aalto University CO:U Fraunhofer IWS Dresden CA2: TK203 CA2: TK610 SDA: MEL Project code: 74717

    PY - 2013

    Y1 - 2013

    N2 - Use of atomic layer deposition (ALD) in microelectromechanical systems (MEMS) has increased as ALD enables conformal growth on 3-dimensional structures at relatively low temperatures. For MEMS device design and fabrication, understanding of the residual stress and mechanical properties of thin film is crucial as these influence directly the device properties and performance. Al2O3 from Me3Al and H2O is one of the most often used materials, but even for that, a detailed study of the mechanical properties as a function of ALD temperature is missing. In this work a comprehensive study of the stress, elastic modulus, hardness and adhesion of atomic layer deposited (ALD) Al2O3 films grown at 110 - 300 °C from trimethylaluminum and deionized water is presented. Film stress was analysed by wafer curvature measurements and Stoney's equation, elastic modulus by nanoindentation and surface-acoustic wave measurements, hardness by nanoindentation, and adhesion by microscratch testing and scanning nanowear measurements. The films were also analysed by ellipsometry, optical reflectometry, x-ray refl ectivity and time-of-flight elastic recoil detection for refractive index, thickness, density and impurities. The ALD Al2O3 films were under tensile stress, in the scale of hundreds of MPa. The magnitude of the residual stress decreased strongly with increasing ALD temperature. Growth-induced stress accounted for most of the stress at low ALD temperature and its importance decreased with increasing ALD temperature. The stress was independent of the type of ALD reactor used. Films grown at 150 to 300 °C had a fairly constant elastic modulus about 170 GPa and hardness of 10-11 GPa. Films grown at 110 °C were softer with a lower elastic modulus, which can at least partly explained by the higher residual hydrogen content in the films. ALD Al2O3 films adhered strongly on RCA-cleaned silicon with SiOx termination. The large set of data obtained in this work as a function of ALD temperature allowed a more detailed observation of the trends in the measured properties than has been possible before. For example, a continuously increasing elastic modulus as a function of ALD temperature was not observed in this study. Instead, after initial increase at low temperature elastic modulus settled to approximately constant value at 150 °C.

    AB - Use of atomic layer deposition (ALD) in microelectromechanical systems (MEMS) has increased as ALD enables conformal growth on 3-dimensional structures at relatively low temperatures. For MEMS device design and fabrication, understanding of the residual stress and mechanical properties of thin film is crucial as these influence directly the device properties and performance. Al2O3 from Me3Al and H2O is one of the most often used materials, but even for that, a detailed study of the mechanical properties as a function of ALD temperature is missing. In this work a comprehensive study of the stress, elastic modulus, hardness and adhesion of atomic layer deposited (ALD) Al2O3 films grown at 110 - 300 °C from trimethylaluminum and deionized water is presented. Film stress was analysed by wafer curvature measurements and Stoney's equation, elastic modulus by nanoindentation and surface-acoustic wave measurements, hardness by nanoindentation, and adhesion by microscratch testing and scanning nanowear measurements. The films were also analysed by ellipsometry, optical reflectometry, x-ray refl ectivity and time-of-flight elastic recoil detection for refractive index, thickness, density and impurities. The ALD Al2O3 films were under tensile stress, in the scale of hundreds of MPa. The magnitude of the residual stress decreased strongly with increasing ALD temperature. Growth-induced stress accounted for most of the stress at low ALD temperature and its importance decreased with increasing ALD temperature. The stress was independent of the type of ALD reactor used. Films grown at 150 to 300 °C had a fairly constant elastic modulus about 170 GPa and hardness of 10-11 GPa. Films grown at 110 °C were softer with a lower elastic modulus, which can at least partly explained by the higher residual hydrogen content in the films. ALD Al2O3 films adhered strongly on RCA-cleaned silicon with SiOx termination. The large set of data obtained in this work as a function of ALD temperature allowed a more detailed observation of the trends in the measured properties than has been possible before. For example, a continuously increasing elastic modulus as a function of ALD temperature was not observed in this study. Instead, after initial increase at low temperature elastic modulus settled to approximately constant value at 150 °C.

    KW - ALD

    KW - Atomic Layer Deposition

    KW - Al2O3

    M3 - Conference abstract in proceedings

    BT - Technical Program & Abstracts, published abstract of a poster

    PB - American Vacuum Society AVS

    ER -

    Ylivaara O, Liu X, Kilpi L, Lyytinen J, Schneider D, Laitinen M et al. ALD Al2O3 from TMA and water on Si: residual stress, elastic modulus, hardness and adhesion: residual stress, elastic modulus, hardness and adhesion. In Technical Program & Abstracts, published abstract of a poster. American Vacuum Society AVS. 2013