Direct observations of rapid diffusion of Cu in Au thin films using in situ x-ray diffraction

Elmer, J. W.; Palmer, T. A.; Specht, E. D.

doi:doi:10.1116/1.2204926

Volume/Page
Keyword
DOI
Citation
Advanced

Volume: Page/Article:

Search Content Type

article doi:

Citation:

You are not logged in to this journal. Log In

Journal of Vacuum Science & Technology A / Volume 24 / Issue 4 / Regular Articles

Previous Article | Next Article

J. Vac. Sci. Technol. A 24, 978 (2006); http://dx.doi.org/10.1116/1.2204926 (10 pages)

Direct observations of rapid diffusion of Cu in Au thin films using in situ x-ray diffraction

J. W. Elmer¹, T. A. Palmer¹, and E. D. Specht²

¹Lawrence Livermore National Laboratory, Livermore, California 94551
²Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831

View Map

(Published online 22 May 2006)

Abstract

References (20)

Citing Articles (4)

Article Objects (14)

Alerts
- Alert Me When Cited
- Alert Me When Corrected
Tools
Share
- Email Abstract
- Connotea
- CiteULike
- del.icio.us
- BibSonomy
- Tweet this Article
- Add to Facebook

Full Text: Read Online (HTML) | Download PDF | Rent Article | Buy PDF (US$28) | View Cart

In situ x-ray diffraction was performed while annealing thin film Au/Cu binary diffusion couples to directly observe diffusion at elevated temperatures. The temperature dependence of the interdiffusion coefficient was determined from isothermal measurements at 700, 800, and 900 °C, where Cu and Au form a disordered continuous face centered cubic solid solution. Large differences in the lattice parameters of Au and Cu allowed the initial diffraction peaks to be easily identified, and later tracked as they merged into one diffraction peak with increased diffusion time. Initial diffusion kinetics were studied by measuring the time required for the Cu to diffuse through the Au thin film of known thickness. The activation energy for interdiffusion was measured to be 65.4 kJ/mole during this initial stage, which is approximately 0.4× that for bulk diffusion and 0.8× that for grain boundary diffusion. The low activation energy is attributed to the high density of columnar grain boundaries combined with other defects in the sputter deposited thin film coatings. As interdiffusion continues, the two layers homogenize with an activation energy of 111 kJ/mole during the latter stages of diffusion. This higher activation energy falls between the reported values for grain boundary and bulk diffusion, and may be related to grain growth occurring at these temperatures which accounts for the decreasing importance of grain boundaries on diffusion.

ACKNOWLEDGMENTS

This work was performed under the auspices of the U.S. Department of Energy, Lawrence Livermore National Laboratory, under Contract No. W-7405-ENG-48. Part of the research was sponsored by the U.S. Department of Energy Division of Materials Sciences and Engineering under contract No. DE-AC05-00OR22725 with UT-Battelle, LLC. The UNICAT facility at the Advanced Photon Source (APS) is supported by the U.S. DOE under Award No. DEFG02-91ER45439, through the Frederick Seitz Materials Research Laboratory at the University of Illinois at Urbana-Champaign, the Oak Ridge National Laboratory (U.S. DOE Contract No. DE-AC05-00OR22725 with UT-Battelle LLC), the National Institute of Standards and Technology (U.S. Department of Commerce) and UOP LLC. The APS is supported by the U.S. DOE, Basic Energy Sciences, Office of Science under Contract No. W-31-109-ENG-38. The authors express gratitude to Ron Forman of LLNL for preparing the PVD coatings and Edwin Sedillo of LLNL for performing scanning electron microscopy.

Article Outline

INTRODUCTION
EXPERIMENTAL PROCEDURES
1. Sample preparation
2. In situ x-ray diffraction experiments
RESULTS
1. General observations and initial sample condition
2. Elevated temperature experiments
DISCUSSION
1. Initial stages of interdiffusion
2. Later stages of diffusion
3. Characterization of the films
CONCLUSIONS

View more related articles.

KEYWORDS and PACS

Keywords

copper, gold, metallic thin films, chemical interdiffusion, X-ray diffraction, lattice constants, grain boundary diffusion

PACS

66.30.Ny

Chemical interdiffusion; diffusion barriers
68.35.Fx

Diffusion; interface formation
61.72.Mm

Grain and twin boundaries

RELATED DATABASES

To view database links for this article, you need to log in.

History

Received 22 December 2005
Accepted 17 April 2006
Published online 22 May 2006

Digital Object Identifier

http://dx.doi.org/10.1116/1.2204926

PUBLICATION DATA

ISSN

0734-2101 (print)

Publisher

American Vacuum Society

For access to fully linked references, you need to log in.

For access to citing articles, you need to log in.

Figures (13) Tables (1)

Access to article objects (figures, tables, multimedia) requires a subscription; log in to view available files.
(Access to supplementary files, where available, is free for this journal.)