The structure and stability of β-Ta thin films

TY - JOUR

T1 - The structure and stability of β-Ta thin films

AU - Jiang, Aiqin

AU - Tyson, Trevor A.

AU - Axe, Lisa

AU - Gladczuk, Leszek

AU - Sosnowski, Marek

AU - Cote, Paul

N1 - Funding Information: This work is supported by the Sustainable Green Manufacturing Program, through the National Defense Center for Environmental Excellence, contract DAAE30-98-C-1050. We would like to thank Dr. L. Keller (CAMET Research, Inc.) for X-ray diffraction measurements and helpful discussions and Dr. N. M. Jisrawi for helpful advice and discussions on the molecular dynamics simulations.

PY - 2005/5/23

Y1 - 2005/5/23

N2 - Ta films with tetragonal crystalline structure (β-phase), deposited by magnetron sputtering on different substrates (steel, silicon, and silicon dioxide), have been studied. In all cases, very highly preferred (001) orientation was observed in X-ray diffraction measurements. All diffraction data revealed two weak reflections corresponding to d-spacing of 0.5272 and 0.1777 nm. The presence of the two peaks, attributed to (001) and (003) reflections, indicates that β-Ta films exhibit a high preference for the space group of P-421m over P42/mnm, previously proposed for β-Ta. Differences in relative intensities of (00l) reflections, calculated for single crystal β-Ta σ-type Frank-Kasper structure and those measured in the films, are attributed to defects in the films. Molecular dynamics simulations performed on tantalum clusters with six different initial configurations using the embedded-atom-method potential revealed the stability of β-Ta, which might explain its growth on many substrates under various deposition conditions.

AB - Ta films with tetragonal crystalline structure (β-phase), deposited by magnetron sputtering on different substrates (steel, silicon, and silicon dioxide), have been studied. In all cases, very highly preferred (001) orientation was observed in X-ray diffraction measurements. All diffraction data revealed two weak reflections corresponding to d-spacing of 0.5272 and 0.1777 nm. The presence of the two peaks, attributed to (001) and (003) reflections, indicates that β-Ta films exhibit a high preference for the space group of P-421m over P42/mnm, previously proposed for β-Ta. Differences in relative intensities of (00l) reflections, calculated for single crystal β-Ta σ-type Frank-Kasper structure and those measured in the films, are attributed to defects in the films. Molecular dynamics simulations performed on tantalum clusters with six different initial configurations using the embedded-atom-method potential revealed the stability of β-Ta, which might explain its growth on many substrates under various deposition conditions.

KW - Clusters

KW - Molecular dynamics

KW - Space group

KW - X-ray diffraction

KW - β-tantalum

KW - σ-type Frank-Kasper structure

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U2 - 10.1016/j.tsf.2004.12.006

DO - 10.1016/j.tsf.2004.12.006

M3 - Article

SN - 0040-6090

VL - 479

SP - 166

EP - 173

JO - Thin Solid Films

JF - Thin Solid Films

IS - 1-2

ER -