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Title: Epitaxial growth of tungsten layers on MgO(001)

Abstract

Smooth single crystal W(001) layers were grown on MgO(001) substrates by magnetron sputtering at 900 °C. X-ray diffraction ω–2θ scans, ω-rocking curves, pole figures, and reciprocal space maps indicate a 45°-rotated epitaxial relationship: (001){sub W}‖(001){sub MgO} and [010]{sub W}‖[110]{sub MgO}, and a relaxed lattice constant of 3.167 ± 0.001 nm. A residual in-plane biaxial compressive strain is primarily attributed to differential thermal contraction after growth and decreases from −0.012 ± 0.001 to −0.001 ± 0.001 with increasing layer thickness d = 4.8–390 nm, suggesting relaxation during cooling by misfit dislocation growth through threading dislocation glide. The in-plane x-ray coherence length increases from 3.4 to 33.6 nm for d = 4.8–390 nm, while the out-of-plane x-ray coherence length is identical to the layer thickness for d ≤ 20 nm, but is smaller than d for d ≥ 49.7 nm, indicating local strain variations along the film growth direction. X-ray reflectivity analyses indicate that the root-mean-square surface roughness increases from 0.50 ± 0.05 to 0.95 ± 0.05 nm for d = 4.8–19.9 nm, suggesting a roughness exponent of 0.38, but remains relatively constant for d > 20 nm with a roughness of 1.00 ± 0.05 nm at d = 47.9 nm.

Authors:
; ;  [1]
  1. Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)
Publication Date:
OSTI Identifier:
22479672
Resource Type:
Journal Article
Journal Name:
Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films
Additional Journal Information:
Journal Volume: 33; Journal Issue: 6; Other Information: (c) 2015 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0734-2101
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; COHERENCE LENGTH; DISLOCATIONS; EPITAXY; LAYERS; MAGNESIUM OXIDES; MAGNETRONS; MONOCRYSTALS; NEUTRON DIFFRACTION; ROUGHNESS; THICKNESS; TUNGSTEN; X RADIATION; X-RAY DIFFRACTION

Citation Formats

Zheng, Pengyuan, Ozsdolay, Brian D., and Gall, Daniel. Epitaxial growth of tungsten layers on MgO(001). United States: N. p., 2015. Web. doi:10.1116/1.4928409.
Zheng, Pengyuan, Ozsdolay, Brian D., & Gall, Daniel. Epitaxial growth of tungsten layers on MgO(001). United States. https://doi.org/10.1116/1.4928409
Zheng, Pengyuan, Ozsdolay, Brian D., and Gall, Daniel. 2015. "Epitaxial growth of tungsten layers on MgO(001)". United States. https://doi.org/10.1116/1.4928409.
@article{osti_22479672,
title = {Epitaxial growth of tungsten layers on MgO(001)},
author = {Zheng, Pengyuan and Ozsdolay, Brian D. and Gall, Daniel},
abstractNote = {Smooth single crystal W(001) layers were grown on MgO(001) substrates by magnetron sputtering at 900 °C. X-ray diffraction ω–2θ scans, ω-rocking curves, pole figures, and reciprocal space maps indicate a 45°-rotated epitaxial relationship: (001){sub W}‖(001){sub MgO} and [010]{sub W}‖[110]{sub MgO}, and a relaxed lattice constant of 3.167 ± 0.001 nm. A residual in-plane biaxial compressive strain is primarily attributed to differential thermal contraction after growth and decreases from −0.012 ± 0.001 to −0.001 ± 0.001 with increasing layer thickness d = 4.8–390 nm, suggesting relaxation during cooling by misfit dislocation growth through threading dislocation glide. The in-plane x-ray coherence length increases from 3.4 to 33.6 nm for d = 4.8–390 nm, while the out-of-plane x-ray coherence length is identical to the layer thickness for d ≤ 20 nm, but is smaller than d for d ≥ 49.7 nm, indicating local strain variations along the film growth direction. X-ray reflectivity analyses indicate that the root-mean-square surface roughness increases from 0.50 ± 0.05 to 0.95 ± 0.05 nm for d = 4.8–19.9 nm, suggesting a roughness exponent of 0.38, but remains relatively constant for d > 20 nm with a roughness of 1.00 ± 0.05 nm at d = 47.9 nm.},
doi = {10.1116/1.4928409},
url = {https://www.osti.gov/biblio/22479672}, journal = {Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films},
issn = {0734-2101},
number = 6,
volume = 33,
place = {United States},
year = {Sun Nov 15 00:00:00 EST 2015},
month = {Sun Nov 15 00:00:00 EST 2015}
}