Hardness enhancement in nanocrystalline tantalum thin films

Zhang, M.; Yang, Bin; Chu, Jinn P.; Nieh, T.G.

doi:10.1016/j.scriptamat.2005.12.027

Cited by 80 publications

(34 citation statements)

References 17 publications

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“…15 The scanning electron micrographs of ASDCM-and NDCM-deposited Ta films at different substrate temperatures are shown in Figs. The results of NDCM grown Ta thin films at 673 K are in good agreement with the recently reported values on nanocrystalline Ta thin films.…”

Section: Resultsmentioning

confidence: 99%

Effect of arc suppression on the physical properties of low temperature dc magnetron sputtered tantalum thin films

Subrahmanyam

Valleti

Joshi

et al. 2007

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

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Effects of deposition parameters on residual stresses, hardness and electrical resistivity of nanoscale twinned 330 stainless steel thin films J. Appl. Phys. 97, 094302 (2005); 10.1063/1.1883724Reactive magnetron sputtering of CN x films: Ion bombardment effects and process characterization using optical emission spectroscopy Arcing is a common phenomenon in the sputtering process. Arcs and glow discharges emit electrons which may influence the physical properties of films. This article reports the properties of tantalum ͑Ta͒ thin films prepared by continuous dc magnetron sputtering in normal and arc-suppression modes. The substrate temperature was varied in the range of 300-673 K. The tantalum films were ϳ1.8 m thick and have good adherence to 316 stainless steel and single-crystal silicon substrates. The phase of the Ta thin film determines the electrical and tribological properties. The films deposited at 300 K using both methods were crystallized in a tetragonal structure ͑␤ phase͒ with a smooth surface ͑grain size of ϳ10 nm͒ and exhibited an electrical resistivity of ϳ194 ⍀ cm and a hardness of ϳ20 GPa. When the substrate temperature was 473 K and higher, the arc-suppression mode appears to influence the films to crystallize in the ␣ phase with a grain size of ϳ40 nm, whereas the normal power mode gave mixed phases ␤ and ␣ beyond 473 K, the arc-suppression mode yields larger grain sizes in the Ta thin films and the hardness decreases. These changes in the physical properties in arc-suppression mode are attributed to either the change in plasma characteristics or the energetic particle bombardment onto the substrate, or both.

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Section: Resultsmentioning

confidence: 99%

Effect of arc suppression on the physical properties of low temperature dc magnetron sputtered tantalum thin films

Subrahmanyam

Valleti

Joshi

et al. 2007

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

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“…In the table, it appears that the larger the grain size, the larger the parameter. Examining Equation (3) against reported flow stress data for other nanocrystalline BCC metals, such as Ta and Mo [24], also suggests the correction to . When the correction factor may not be accurately obtained from dislocation theory, Equation (4) provides a means to evaluate it from the Hall-Petch type fitting of experimental data.…”

Section: Prediction For Bcc Metalsmentioning

confidence: 98%

Revisiting the intra-granular dislocation extension model for flow stress in nanocrystalline metals

Kad

Dao

2012

Philosophical Magazine Letters

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In our previous work (R.J. Asaro, P. Krysl and B. Kad, Philos. Mag. Lett. 83 (2003) p.733; P. Gu, B. Kad and M. Dao, Scr. Mater. 62 (2010) p.361), the intra-granular partial dislocation extension model was shown to be consistent with the experimental data of flow stress in nanocrystalline FCC materials. However, since the averaged extension was taken for a nonuniform loop, the model predicted small dislocation extension across the grain. In this article, extending our previous work, we reformulate the intra-granular partial dislocation model for FCC nanocrystalline materials using a more realistic loop. The flow stress obtained from the reformulated model shows good agreement with experimental data for various nanocrystalline FCC materials and expectedly large dislocation extension across the grain. In the second portion of this article, the mechanistic model for partial dislocation extension is extended to develop an intra-granular perfect dislocation extension model. The perfect dislocation model is examined by comparing its prediction of flow stress with experimental data of nanocrystalline Fe. Additionally, activation volume and strain-rate sensitivity are discussed within the mechanistic model in the light of available experimental data on nanocrystalline Fe.

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“…Thus, the use of Ta interlayers gives us the opportunity, in comparison to the studies without interlayer [9,10] to further improve the tolerance to local impact. Due to the difference in the crystallographic unit cells α-Ta is softer and more ductile compared to β-Ta [14][15][16]. Hence, DLC coated Ti substrates with α-and β-Ta interlayer (from now on termed α-Ta/DLC and β-Ta/DLC) are analyzed in this study.…”

Section: Introductionmentioning

confidence: 99%

Improved contact damage resistance of hydrogenated diamond-like carbon (DLC) with a ductile α-Ta interlayer

Bernoulli

Rico

Wyss

et al. 2015

Diamond and Related Materials

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Hardness enhancement in nanocrystalline tantalum thin films

Cited by 80 publications

References 17 publications

Effect of arc suppression on the physical properties of low temperature dc magnetron sputtered tantalum thin films

Effect of arc suppression on the physical properties of low temperature dc magnetron sputtered tantalum thin films

Revisiting the intra-granular dislocation extension model for flow stress in nanocrystalline metals

Improved contact damage resistance of hydrogenated diamond-like carbon (DLC) with a ductile α-Ta interlayer

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