Hillock formation in co-deposited thin films of immiscible metal alloy systems
Abstract
Hillocks are protruding sections of a surface that can influence the electronic and mechanical properties of a thin film. In monolithic films, these hillocks are formed due to thermally induced stress gradients during deposition. In this study, the surface morphology of co-sputtered immiscible Cu-X (X is a body centered cubic (BCC) group V or VI metal) thin films is characterized to elucidate the conditions that lead to hillock formation. Cu-Ta and Cu-Mo-Ag films were co-deposited with physical vapor deposition (PVD) magnetron sputtering at 25, 400, 600, and 800°C. A significant number of homogeneously distributed surface hillocks were observed only in the 600 and 800°C films. High-angle annular dark field (HAADF) cross-sectional imaging revealed significant Cu agglomerations underneath the protruding features. For the Cu-Ta films, the Cu was enveloped in a Cu-Ta nanocrystalline matrix. For Cu-Mo-Ag, the Cu was surrounded by Mo-Ag concentration modulations. While thermal stress gradients arise during deposition of immiscible metal films, biaxial stress calculations and literature cases reveal that they are not solely responsible for hillock formation. The observed morphologies align with a surface diffusion kinetic model that evaluates diffusion length of adatoms during deposition as a function of deposition temperature. Finally, this indicates a phase separationmore »
- Authors:
-
- Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Materials Science and Engineering
- Publication Date:
- Research Org.:
- Univ. of Michigan, Ann Arbor, MI (United States)
- Sponsoring Org.:
- USDOE National Nuclear Security Administration (NNSA)
- OSTI Identifier:
- 1574372
- Alternate Identifier(s):
- OSTI ID: 1776253
- Grant/Contract Number:
- NA0003857
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Thin Solid Films
- Additional Journal Information:
- Journal Volume: 693; Journal Issue: C; Journal ID: ISSN 0040-6090
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 36 MATERIALS SCIENCE; copper tantalum; thin films; hillock formation; immiscible alloys; sputtering
Citation Formats
Powers, Max, Derby, Benjamin, Raeker, Evan, Champion, Nicholas, and Misra, Amit. Hillock formation in co-deposited thin films of immiscible metal alloy systems. United States: N. p., 2019.
Web. doi:10.1016/j.tsf.2019.137692.
Powers, Max, Derby, Benjamin, Raeker, Evan, Champion, Nicholas, & Misra, Amit. Hillock formation in co-deposited thin films of immiscible metal alloy systems. United States. https://doi.org/10.1016/j.tsf.2019.137692
Powers, Max, Derby, Benjamin, Raeker, Evan, Champion, Nicholas, and Misra, Amit. Fri .
"Hillock formation in co-deposited thin films of immiscible metal alloy systems". United States. https://doi.org/10.1016/j.tsf.2019.137692. https://www.osti.gov/servlets/purl/1574372.
@article{osti_1574372,
title = {Hillock formation in co-deposited thin films of immiscible metal alloy systems},
author = {Powers, Max and Derby, Benjamin and Raeker, Evan and Champion, Nicholas and Misra, Amit},
abstractNote = {Hillocks are protruding sections of a surface that can influence the electronic and mechanical properties of a thin film. In monolithic films, these hillocks are formed due to thermally induced stress gradients during deposition. In this study, the surface morphology of co-sputtered immiscible Cu-X (X is a body centered cubic (BCC) group V or VI metal) thin films is characterized to elucidate the conditions that lead to hillock formation. Cu-Ta and Cu-Mo-Ag films were co-deposited with physical vapor deposition (PVD) magnetron sputtering at 25, 400, 600, and 800°C. A significant number of homogeneously distributed surface hillocks were observed only in the 600 and 800°C films. High-angle annular dark field (HAADF) cross-sectional imaging revealed significant Cu agglomerations underneath the protruding features. For the Cu-Ta films, the Cu was enveloped in a Cu-Ta nanocrystalline matrix. For Cu-Mo-Ag, the Cu was surrounded by Mo-Ag concentration modulations. While thermal stress gradients arise during deposition of immiscible metal films, biaxial stress calculations and literature cases reveal that they are not solely responsible for hillock formation. The observed morphologies align with a surface diffusion kinetic model that evaluates diffusion length of adatoms during deposition as a function of deposition temperature. Finally, this indicates a phase separation driving force paired with the constituent elements’ dissimilar mobilities at elevated deposition temperatures contribute to the presence of hillocks.},
doi = {10.1016/j.tsf.2019.137692},
journal = {Thin Solid Films},
number = C,
volume = 693,
place = {United States},
year = {Fri Nov 08 00:00:00 EST 2019},
month = {Fri Nov 08 00:00:00 EST 2019}
}
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Works referenced in this record:
Hillock growth in thin films
journal, October 1974
- Chaudhari, P.
- Journal of Applied Physics, Vol. 45, Issue 10
In situ study of stress relaxation mechanisms of pure Al thin films during isothermal annealing
journal, June 2006
- Hwang, Soo-Jung; Lee, Yong-Duck; Park, Young-Bae
- Scripta Materialia, Vol. 54, Issue 11
Whisker and Hillock formation on Sn, Sn–Cu and Sn–Pb electrodeposits
journal, November 2005
- Boettinger, W. J.; Johnson, C. E.; Bendersky, L. A.
- Acta Materialia, Vol. 53, Issue 19, p. 5033-5050
Stress relaxation and hillock growth in thin films
journal, November 1982
- Jackson, M. S.; Che-yu, Li
- Acta Metallurgica, Vol. 30, Issue 11
Formation of hillocks in Pt/Ti electrodes and their effects on short phenomena of PZT films deposited by reactive sputtering
journal, August 2000
- Nam, Hyo-Jin; Choi, Duck-Kyun; Lee, Won-Jong
- Thin Solid Films, Vol. 371, Issue 1-2
Stress distribution and hillock formation in Au/Pd thin films as a function of aging treatment in capacitor applications
journal, August 2009
- Nazarpour, S.; Jambois, O.; Zamani, C.
- Applied Surface Science, Vol. 255, Issue 22
Stability of amorphous Cu/Ta and Cu/W alloys
journal, October 1985
- Nastasi, M.; Saris, F. W.; Hung, L. S.
- Journal of Applied Physics, Vol. 58, Issue 8
Influence of apparatus geometry and deposition conditions on the structure and topography of thick sputtered coatings
journal, July 1974
- Thornton, John A.
- Journal of Vacuum Science and Technology, Vol. 11, Issue 4
Effects of substrate temperature and deposition rate on the phase separated morphology of co-sputtered, Cu-Mo thin films
journal, February 2018
- Derby, B.; Cui, Y.; Baldwin, J. K.
- Thin Solid Films, Vol. 647
Processing of novel pseudomorphic Cu–Mo hierarchies in thin films
journal, November 2018
- Derby, Benjamin; Cui, Yuchi; Baldwin, JonKevin
- Materials Research Letters, Vol. 7, Issue 1
A structure zone diagram including plasma-based deposition and ion etching
journal, May 2010
- Anders, André
- Thin Solid Films, Vol. 518, Issue 15
Design of bicontinuous metallic nanocomposites for high-strength and plasticity
journal, March 2019
- Cui, Yuchi; Derby, Benjamin; Li, Nan
- Materials & Design, Vol. 166
Suppression of shear banding in high-strength Cu/Mo nanocomposites with hierarchical bicontinuous intertwined structures
journal, December 2017
- Cui, Yuchi; Derby, Benjamin; Li, Nan
- Materials Research Letters, Vol. 6, Issue 3
Stability of interfaces in Mo/Cu multilayered metallization
journal, May 1996
- Luby, S.; Majkov, E.; Jergel, M.
- Thin Solid Films, Vol. 277, Issue 1-2
Investigation on the interfacial stability of multilayered Cu–W films at elevated deposition temperatures during co-sputtering
journal, August 2019
- Xue, Jiawei; Li, Yanhuai; Hao, Liucheng
- Vacuum, Vol. 166