Structural and mechanical properties of sputtered cubic and hexagonal NbNx thin films

Benkahoul, M.; Martínez, E.; Karimi, A.; Sanjinés, R.; Lévy, F.

doi:10.1016/j.surfcoat.2003.10.040

Cited by 111 publications

(58 citation statements)

References 12 publications

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“…This means that interface formation does not result in a strengthening of the nanocomposites based on NbN/SiN x from a chemical bonding perspective, as was shown for TiN/SiN x heterostructures [53]. Due to symmetry and the specific electronic structure of different phases of NbN [54] the values of s T for the hexagonal structures are higher than for the cubic ones, for which reason the mechanical characteristics for ε-NbN films should be higher than for δ-NbN ones, in agreement with experiments [14,15]. Several important features can be gained from these calculations to understand experimental findings.…”

Section: Theoretical Results and The Interpretation Of Experimental Datasupporting

confidence: 85%

“…The hardness of the NbN films deposited by different arc deposition systems reaches 34-49 GPa [8][9][10][11][12][13]. The NbN films were also prepared by using magnetron sputtering (MS) [14][15][16][17][18], ion Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/ceramint beam assisted deposition [19], pulsed laser deposition [20]. An increase in hardness was reached by the formation of the nanocomposite or nanolayered structures in ternary Nb-Si-N films [21][22][23][24][25][26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

“…It was shown that the NbN system crystallizes in different structural phases: cubic δ-NbN (a small number of vacancies are present in both the sublattices, space group Fm-3m) and hexagonal ε-NbN (space group P-6 m2) and δ ′-NbN (space group P6 3 /mmc), depending on deposition parameters. The formation of the hexagonal phases occurs at high nitrogen partial pressures and substrate biases [14][15][16]18]. The hardness of the hexagonal δ′ and ε phases of NbN is higher compared to that of the cubic δ-NbN [14,15].…”

Section: Introductionmentioning

confidence: 99%

“…The formation of the hexagonal phases occurs at high nitrogen partial pressures and substrate biases [14][15][16]18]. The hardness of the hexagonal δ′ and ε phases of NbN is higher compared to that of the cubic δ-NbN [14,15]. The addition of silicon up to 3.4 at% led to an increase in hardness up to 53 GPa [21].…”

Section: Introductionmentioning

confidence: 99%

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Structural and mechanical properties of NbN and Nb-Si-N films: Experiment and molecular dynamics simulations

Pogrebnjak

Бондар

Abadias

et al. 2016

Ceramics International

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a b s t r a c tThe structural and mechanical properties of NbN and Nb-Si-N films have been investigated both experimentally and theoretically, in their as-deposited and annealed states. The films were deposited using magnetron sputtering at substrate bias (U B ) between 0 and À 70 V. While NbN films were found to crystallize in the cubic δ-NbN structure, Nb-Si-N films with Si content of 11-13 at% consisted of a twophases nanocomposite structure where δ-NbN nanocrystals were embedded in SiN x amorphous matrix.Films deposited at U B ¼0 V were highly (001)-textured. Application of substrate bias potential led to a depletion of light atoms, and caused a grain size refinement concomitantly with the increase of (111) preferred orientations in both films. The maximum hardness was 28 GPa and 32 GPa for NbN and Nb-Si-N films, respectively. NbN and Nb-Si-N films deposited at U B ¼ À70 V exhibited compressive stress of À 3 and À 4 GPa, respectively. After vacuum annealing, a decrease in the stress-free lattice parameter was observed for both films, and attributed to alteration of film composition. To obtain insights on interface properties and related mechanical and thermal stability of Nb-Si-N nanocomposite films, first principles molecular dynamics simulations of NbN/SiN x heterostructures with different structures (cubic and hexagonal) and atomic configurations were carried out. All the hexagonal heterostructures were found to be dynamically stable and weakly dependent on temperature. Calculation of the tensile strain-stress curves showed that the values of ideal tensile strength for the δ-NbN(111)-and ε-NbN(001)-based heterostructures with coherent interfaces and Si 3 N 4 -like Si 2 N 3 interfaces were the highest with values in the range 36-65 GPa, but lower than corresponding values of bulk NbN compound. This suggests that hardness enhancement is likely due to inhibition of dislocation glide at the grain boundary rather than interfacial strengthening due to Si-N chemical bonding.

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Section: Theoretical Results and The Interpretation Of Experimental Datasupporting

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Structural and mechanical properties of NbN and Nb-Si-N films: Experiment and molecular dynamics simulations

Pogrebnjak

Бондар

Abadias

et al. 2016

Ceramics International

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“…Note that the cubic ␦-NbN superconducting phase has a the bulk modulus of 348 GPa, comparable to that of cubic boron nitride, and a Vickers hardness of 20 GPa, the same as sapphire. Recent studies in films (23) revealed that the hardness of the hexagonal ␦Ј-NbN phase with high nitrogen concentration can reach to 40 GPa. The relatively large bulk modulus and high hardness in the superconducting cubic ␦-NbN phase are favorable for potential hard-device applications.…”

Section: Resultsmentioning

confidence: 99%

Hard superconducting nitrides

Chen

Struzhkin²,

Wu³

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

269

137

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Detailed study of the equation of state, elasticity, and hardness of selected superconducting transition-metal nitrides reveals interesting correlations among their physical properties. Both the bulk modulus and Vickers hardness are found to decrease with increasing zero-pressure volume in NbN, HfN, and ZrN. The computed elastic constants from first principles satisfy c11 > c12 > c44 for NbN, but c11 > c44 > c12 for HfN and ZrN, which are in good agreement with the neutron scattering data. The cubic ␦-NbN superconducting phase possesses a bulk modulus of 348 GPa, comparable to that of cubic boron nitride, and a Vickers hardness of 20 GPa, which is close to sapphire. Theoretical calculations for NbN show that all elastic moduli increase monotonically with increasing pressure. These results suggest technological applications of such materials in extreme environments.elasticity ͉ elastic constants ͉ equations of state ͉ hardness ͉ binary compounds H ard superconducting materials are of considerable interest for specific electronic applications. Superconductivity has been discovered in diamond, generally believed to be the hardest material having very high shear and bulk moduli (1, 2), with a superconducting transition temperature (T c ) near 4 K when doped with boron (3). However, the transition-metal compounds having the sodium chloride (B1) structure (e.g., NbN, NbC, ZrN, or HfN) are also hard superconductors but with relatively higher T c s. The transition temperatures of solid solutions of NbN and NbC can reach a maximum value of 17.8 K, which is close to those found for the cubic A15-type compounds such as Nb 3 Sn and V 3 Si (4). The refractory characteristics of these transitionmetal nitrides and carbides have been applied as coatings to increase the wear resistance, for instance, in cutting tools as well as for magnetic storage devices. The unusual hardness enhancement in these materials has been theoretically shown to originate from a particular -band of bonding states between the nonmetal p orbitals and the metal d orbitals that strongly resists shearing strains (5). At the moment, there is a need to investigate elastic and mechanical properties of these superconductors under simulated extreme working conditions.Here, we report both experimental and theoretical studies of the equation of state, elasticity, and hardness of selected superconducting transition-metal nitrides. We find that the cubic ␦-NbN superconducting phase possesses a bulk modulus of 348 GPa, comparable to that of cubic boron nitride, and a Vickers hardness of 20 GPa, which is close to sapphire (Al 2 O 3 ) (6). The results indicate that these nitrides are good candidates for engineering hard superconducting materials. Experimental and Theoretical DetailsEquations of state studies were based on angle-dispersive synchrotron powder x-ray diffractometry with a diamond anvil cell. The diffraction experiments were carried out at the synchrotron beam line 16ID-B of the Advanced Photon Source High Pressure Collaborative Access Team. A 500 ϫ 500-m ...

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Investigation of the Crystal Structure on the Nanomechanical Properties of Pulsed Laser Deposited NbN Thin Films

Mamun

Farha

Ufuktepe

et al. 2012

Supplemental Proceedings

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Structural and mechanical properties of sputtered cubic and hexagonal NbNx thin films

Cited by 111 publications

References 12 publications

Structural and mechanical properties of NbN and Nb-Si-N films: Experiment and molecular dynamics simulations

Structural and mechanical properties of NbN and Nb-Si-N films: Experiment and molecular dynamics simulations

Hard superconducting nitrides

Investigation of the Crystal Structure on the Nanomechanical Properties of Pulsed Laser Deposited NbN Thin Films

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