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Title: Direct Observations of Rapid Diffusion of Cu in Au Thin Films Using In-Situ X-Ray Diffraction

Abstract

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 0.4x that for bulk diffusion and 0.8x 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 maymore » be related to grain growth occurring at these temperatures which accounts for the decreasing importance of grain boundaries on diffusion.« less

Authors:
 [1];  [1];  [2]
  1. Lawrence Livermore National Laboratory (LLNL)
  2. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1003602
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Vacuum Science & Technology A; Journal Volume: 24; Journal Issue: 4
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; COPPER; DIFFUSION; GOLD; INCLUSIONS; X-RAY DIFFRACTION; THIN FILMS; ACTIVATION ENERGY; ANNEALING; FCC LATTICES; GRAIN BOUNDARIES; KINETICS; TEMPERATURE DEPENDENCE

Citation Formats

Elmer, J. W., Palmer, T. A., and Specht, Eliot D. Direct Observations of Rapid Diffusion of Cu in Au Thin Films Using In-Situ X-Ray Diffraction. United States: N. p., 2006. Web. doi:10.1116/1.2204926.
Elmer, J. W., Palmer, T. A., & Specht, Eliot D. Direct Observations of Rapid Diffusion of Cu in Au Thin Films Using In-Situ X-Ray Diffraction. United States. doi:10.1116/1.2204926.
Elmer, J. W., Palmer, T. A., and Specht, Eliot D. Sun . "Direct Observations of Rapid Diffusion of Cu in Au Thin Films Using In-Situ X-Ray Diffraction". United States. doi:10.1116/1.2204926.
@article{osti_1003602,
title = {Direct Observations of Rapid Diffusion of Cu in Au Thin Films Using In-Situ X-Ray Diffraction},
author = {Elmer, J. W. and Palmer, T. A. and Specht, Eliot D},
abstractNote = {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 0.4x that for bulk diffusion and 0.8x 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.},
doi = {10.1116/1.2204926},
journal = {Journal of Vacuum Science & Technology A},
number = 4,
volume = 24,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}