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Title: Effects of thermal annealing on the microstructure of sputtered Al{sub 2}O{sub 3} coatings

Abstract

The morphology and microstructure of Al{sub 2}O{sub 3} thin films deposited by pulsed direct current magnetron sputtering were studied in the as-grown state and after vacuum annealing at 1000 deg. C for 12 h using transmission electron microscopy. For the coating deposited under low ion bombardment conditions, the film consists of small {gamma}- and/or {delta}-Al{sub 2}O{sub 3} grains embedded in an amorphous matrix. The grain size at the region close to the interface to the substrate was much larger than that of the remaining layer. Growth of the {gamma}-Al{sub 2}O{sub 3} phase is promoted during annealing but no transformation to {alpha}-Al{sub 2}O{sub 3} was detected. For high-energetic growth conditions, clear evidence for {gamma}-Al{sub 2}O{sub 3} formation was found in the upper part of the coating with grain size much larger than for low-energetic growth, but the film was predominately amorphous at the interface region. Annealing resulted in the transformation of {gamma}-Al{sub 2}O{sub 3} to {alpha}-Al{sub 2}O{sub 3}, while the mainly amorphous part crystallized to {gamma}-Al{sub 2}O{sub 3}.

Authors:
; ; ; ; ;  [1];  [2];  [3]
  1. Department of Physical Metallurgy and Materials Testing, University of Leoben, A-8700 Leoben (Austria)
  2. (Germany)
  3. (Austria)
Publication Date:
OSTI Identifier:
22054108
Resource Type:
Journal Article
Journal Name:
Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films
Additional Journal Information:
Journal Volume: 29; Journal Issue: 4; Other Information: (c) 2011 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1553-1813
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALUMINIUM OXIDES; AMORPHOUS STATE; ANNEALING; CRYSTAL GROWTH; DEPOSITION; DIRECT CURRENT; GRAIN SIZE; ION BEAMS; MAGNETRONS; MORPHOLOGY; PHASE TRANSFORMATIONS; PROTECTIVE COATINGS; SPUTTERING; THIN FILMS; TRANSMISSION ELECTRON MICROSCOPY

Citation Formats

Edlmayr, V., Harzer, T. P., Hoffmann, R., Kiener, D., Scheu, C., Mitterer, C., Department of Chemistry, Ludwig-Maximilians-University of Munich, D-81377 Munich, and Department of Physical Metallurgy and Materials Testing, University of Leoben, A-8700 Leoben. Effects of thermal annealing on the microstructure of sputtered Al{sub 2}O{sub 3} coatings. United States: N. p., 2011. Web. doi:10.1116/1.3584803.
Edlmayr, V., Harzer, T. P., Hoffmann, R., Kiener, D., Scheu, C., Mitterer, C., Department of Chemistry, Ludwig-Maximilians-University of Munich, D-81377 Munich, & Department of Physical Metallurgy and Materials Testing, University of Leoben, A-8700 Leoben. Effects of thermal annealing on the microstructure of sputtered Al{sub 2}O{sub 3} coatings. United States. doi:10.1116/1.3584803.
Edlmayr, V., Harzer, T. P., Hoffmann, R., Kiener, D., Scheu, C., Mitterer, C., Department of Chemistry, Ludwig-Maximilians-University of Munich, D-81377 Munich, and Department of Physical Metallurgy and Materials Testing, University of Leoben, A-8700 Leoben. Fri . "Effects of thermal annealing on the microstructure of sputtered Al{sub 2}O{sub 3} coatings". United States. doi:10.1116/1.3584803.
@article{osti_22054108,
title = {Effects of thermal annealing on the microstructure of sputtered Al{sub 2}O{sub 3} coatings},
author = {Edlmayr, V. and Harzer, T. P. and Hoffmann, R. and Kiener, D. and Scheu, C. and Mitterer, C. and Department of Chemistry, Ludwig-Maximilians-University of Munich, D-81377 Munich and Department of Physical Metallurgy and Materials Testing, University of Leoben, A-8700 Leoben},
abstractNote = {The morphology and microstructure of Al{sub 2}O{sub 3} thin films deposited by pulsed direct current magnetron sputtering were studied in the as-grown state and after vacuum annealing at 1000 deg. C for 12 h using transmission electron microscopy. For the coating deposited under low ion bombardment conditions, the film consists of small {gamma}- and/or {delta}-Al{sub 2}O{sub 3} grains embedded in an amorphous matrix. The grain size at the region close to the interface to the substrate was much larger than that of the remaining layer. Growth of the {gamma}-Al{sub 2}O{sub 3} phase is promoted during annealing but no transformation to {alpha}-Al{sub 2}O{sub 3} was detected. For high-energetic growth conditions, clear evidence for {gamma}-Al{sub 2}O{sub 3} formation was found in the upper part of the coating with grain size much larger than for low-energetic growth, but the film was predominately amorphous at the interface region. Annealing resulted in the transformation of {gamma}-Al{sub 2}O{sub 3} to {alpha}-Al{sub 2}O{sub 3}, while the mainly amorphous part crystallized to {gamma}-Al{sub 2}O{sub 3}.},
doi = {10.1116/1.3584803},
journal = {Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films},
issn = {1553-1813},
number = 4,
volume = 29,
place = {United States},
year = {2011},
month = {7}
}