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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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.}",
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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