Correlation of W-Si-N Film Microstructure with     Barrier Performance against Cu Diffusion

Shimooka, Y.; Iijima, Tadashi; Nakamura, Shigenari; Suguro, K.

doi:10.1143/jjap.36.1589

Cited by 15 publications

(6 citation statements)

References 9 publications

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“…It was reported that the amorphous structure of reactive-sputter-deposited WSiN layers can be preserved even after annealing at 850ЊC. 33 It was also reported that a very thin (4 nm) WSiN layer can be formed on the WSi x surface by ECR N 2 plasma nitridation and that it functioned as an excellent barrier to dopant diffusion. 34 In this work, the very thin and thermally very stable WSiN layers gave a great help to suppress the Cu diffusion.…”

Section: Resultsmentioning

confidence: 99%

Barrier Capabilities of Selective Chemical Vapor Deposited W Films and WSiN / WSi x / W Stacked Layers Against Cu Diffusion

Wang

Chen

1999

J. Electrochem. Soc.

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This work investigates the barrier capability of W layers as well as WSiN/WSi x /W stacked layers against Cu diffusion. The W layers were selectively chemical vapor deposited (CVD) in contact holes to a thickness of about 450 nm using SiH 4 reduction of WF 6 . We found that the CVD-W layers functioned as effective barriers against Cu diffusion, and the Cu/W(450 nm)/p ϩ -n junction diodes were able to sustain a 30 min furnace annealing up to 650ЊC without causing degradation in electrical characteristics. The use of WSiN/WSi x /W stacked layers as diffusion layers further improved the thermal stability of Cu/WSiN/WSi x /W(450 nm)/p ϩ -n junction diodes to at least 700ЊC. The WSi x layers were deposited by CVD to a thickness of 75 nm using SiH 4 /WF 6 chemistry, and the subsequent in situ N 2 plasma treatment produced a very thin layer of WSiN on the WSi x surface. This thin WSiN layer was very thermally stable and effective in suppressing Cu diffusion. Failure of barrier capability for the W films was presumably due to interdiffusion of Cu and Si along grain boundaries of the W films, and the interdiffusion was probably enhanced by the formation of WSi 2 . The formation of WSi 2 consumed the W layer and Si substrate, resulting in a volume change in barrier layer, which, in turn, developed local defects, such as microcracks and stress-induced weak points, and thus provided fast paths for Cu diffusion.

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Section: Resultsmentioning

confidence: 99%

Barrier Capabilities of Selective Chemical Vapor Deposited W Films and WSiN / WSi x / W Stacked Layers Against Cu Diffusion

Wang

Chen

1999

J. Electrochem. Soc.

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“…In the equilibrium structure of W 2 N, all the N atoms are accommodated in half of the available octahedral interstitial sites. 18,25,29 It was reported that nitrogen in the W 2 N film started to evaporate to vacuum at about 820°C, and was fully released after annealing at 900°C. The thermal annealing above 800°C has removed part of the excessive interstitial N atoms, and consequently the W 2 N ͑111͒ interplanar distance shifts closer to the standard value.…”

Section: Discussionmentioning

confidence: 99%

Thermal stability of sputter deposited nanocrystalline W2N/amorphous Si3N4 coatings

Shen

Zhou

et al. 2006

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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The thermal stability of nanocomposite W-Si-N coatings, which had been sputter deposited at increased silicon target currents, was studied by annealing at 800 or 900°C in vacuum by using x-ray diffraction, x-ray photoelectron spectroscopy, electron probe microanalysis, scanning electron microscopy, atomic force microscopy, and microhardness testing. The crystalline W 2 N coatings were decomposed to W with the loss of interstitial N atoms and the presence of microcracks at their surfaces after annealing at 900°C. The coating consisting of nanocrystalline ͑nc-͒ W 2 N imbedded in amorphous ͑a-͒ Si 3 N 4 matrices and the amorphous coatings underwent partial recrystallization, the loss of interstitial N atoms, and morphological changes upon annealing. The nc-W 2 N/a-Si 3 N 4 coating had the least N in grain boundaries and the lowest atomic O / N ratio, and it had no failure after annealing at 900°C, showing high thermal stability. The hardness of the coatings was decreased, but the nc-W 2 N/a-Si 3 N 4 coating maintained the highest hardness ͑46.6± 3.7 GPa͒ after annealing at 900°C.

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“…Ternary amorphous metallic thin films such as Ti–Si–N [ 1 , 2 , 3 , 4 ], Mo–Si–N [ 5 , 6 ], Zr–Si–N [ 7 , 8 , 9 , 10 ], Ta–Si–N [ 11 , 12 , 13 , 14 , 15 , 16 ], and W–Si–N [ 17 , 18 , 19 , 20 , 21 , 22 , 23 ] have received considerable attention for high temperature diffusion barrier applications. These materials have shown to be chemically inert against reactions with gold [ 4 , 11 , 24 ], silver [ 11 ], copper [ 12 , 13 , 14 , 16 , 17 , 20 ], aluminum [ 18 , 25 ], and platinum [ 26 , 27 , 28 ] metallization at elevated temperatures, thereby providing the low diffusivities required for a diffusion barrier. Moreover, their amorphous structure sustains even at temperatures above 800 °C [ 15 , 20 , 21 ], preventing the formation of grain boundaries which act as rapid diffusion paths.…”

Section: Introductionmentioning

confidence: 99%

“…These materials have shown to be chemically inert against reactions with gold [ 4 , 11 , 24 ], silver [ 11 ], copper [ 12 , 13 , 14 , 16 , 17 , 20 ], aluminum [ 18 , 25 ], and platinum [ 26 , 27 , 28 ] metallization at elevated temperatures, thereby providing the low diffusivities required for a diffusion barrier. Moreover, their amorphous structure sustains even at temperatures above 800 °C [ 15 , 20 , 21 ], preventing the formation of grain boundaries which act as rapid diffusion paths.…”

Section: Introductionmentioning

confidence: 99%

A WSi–WSiN–Pt Metallization Scheme for Silicon Carbide-Based High Temperature Microsystems

et al. 2016

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In this paper, we present and discuss our new WSi–WSiN–Pt metallization scheme for SiC-based microsystems for applications in harsh environments. Stoichiometric material WSi was selected as contact material for SiC. The diffusion barrier material WSiN was deposited from the same target as the contact material in order to limit the number of different chemical elements in the scheme. Our scheme was kept as simple as possible regarding the number of layers and chemical elements. Our scheme shows very good long-term stability and suitability for SiC-based microsystems. The experimental evaluation concept used here includes a combination of physical, electrical, and mechanical analysis techniques. This combined advance is necessary since modern physical analysis techniques still offer only limited sensitivity for detecting minimal changes in the metallization scheme.

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Correlation of W-Si-N Film Microstructure with Barrier Performance against Cu Diffusion

Cited by 15 publications

References 9 publications

Barrier Capabilities of Selective Chemical Vapor Deposited W Films and WSiN / WSi x / W Stacked Layers Against Cu Diffusion

Barrier Capabilities of Selective Chemical Vapor Deposited W Films and WSiN / WSi x / W Stacked Layers Against Cu Diffusion

Thermal stability of sputter deposited nanocrystalline W2N/amorphous Si3N4 coatings

A WSi–WSiN–Pt Metallization Scheme for Silicon Carbide-Based High Temperature Microsystems

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