Elastic constants of tetrahedral amorphous carbon films by surface Brillouin scattering

1999 ◽  
Vol 75 (13) ◽  
pp. 1893-1895 ◽  
Author(s):  
A. C. Ferrari ◽  
J. Robertson ◽  
M. G. Beghi ◽  
C. E. Bottani ◽  
R. Ferulano ◽  
...  
Keyword(s):  
Amorphous Carbon ◽  
Elastic Constants ◽  
Brillouin Scattering ◽  
Carbon Films ◽  
Amorphous Carbon Films ◽  
Tetrahedral Amorphous Carbon

scholarly journals Elastic Constants of Diamond-Like Carbon Films by Surface Brillouin Scattering

1999 ◽  
Vol 593 ◽  
Author(s):  
A.C. Ferrari ◽  
J. Robertson ◽  
R. Pastorelli ◽  
M.G. Beghi ◽  
C.E. Bottani
Keyword(s):  
Thin Films ◽  
Amorphous Carbon ◽  
Elastic Constants ◽  
Acoustic Waves ◽  
Brillouin Scattering ◽  
Surface Acoustic Waves ◽  
Carbon Films ◽  
Diamond Like Carbon ◽  
Amorphous Carbon Films ◽  
Tetrahedral Amorphous Carbon

ABSTRACTThe elastic constants of thin Diamond-Like Carbon (DLC) films supply important information, but their measurement is difficult. Standard nanoindentation does not directly measure the elastic constants and has strong limitations particularly in the case of hard thin films on softer substrates, such as tetrahedral amorphous carbon on Si. Surface acoustic waves provide a better mean to investigate elastic properties. Surface Brillouin scattering (SBS) intrinsically probes acoustic waves of the wavelength which is appropriate to test the properties of films in the tens to hundreds of nanometers thickness range. SBS can be used to derive all the isotropic elastic constants of hard-on-soft and soft-on-hard amorphous carbon films of different kinds, with thickness down to less than 10 nm. The results help to resolve the previous uncertainties in mechanical data. The Young's modulus of tetrahedral amorphous carbon (ta-C) turns out to be lower than that of diamond, while the moduli of hydrogenated ta-C (ta-C:H) are considerably lower than those of ta-C because of the weakening effect of C-H bonding.

scholarly journals Elastic Constants of Diamond Like Carbon Films by Surface Brillouin Scattering

1999 ◽  
Vol 594 ◽  
Author(s):  
A. C. Ferrari ◽  
J. Robertson ◽  
R. Pastorelli ◽  
M. G. Beghi ◽  
C. E. Bottani
Keyword(s):  
Thin Films ◽  
Amorphous Carbon ◽  
Elastic Constants ◽  
Acoustic Waves ◽  
Brillouin Scattering ◽  
Surface Acoustic Waves ◽  
Carbon Films ◽  
Diamond Like Carbon ◽  
Amorphous Carbon Films ◽  
Tetrahedral Amorphous Carbon

AbstractThe elastic constants of thin Diamond-Like Carbon (DLC) films supply important information, but their measurement is difficult. Standard nanoindentation does not directly measure the elastic constants and has strong limitations particularly in the case of hard thin films on softer substrates, such as tetrahedral amorphous carbon on Si. Surface acoustic waves provide a better mean to investigate elastic properties. Surface Brillouin scattering (SBS) intrinsically probes acoustic waves of the wavelength which is appropriate to test the properties of films in the tens to hundreds of nanometers thickness range. SBS can be used to derive all the isotropic elastic constants of hard-on-soft and soft-on-hard amorphous carbon films of different kinds, with thickness down to less than 10 nm. The results help to resolve the previous uncertainties in mechanical data. The Young's modulus of tetrahedral amorphous carbon (ta-C) turns out to be lower than that of diamond, while the moduli of hydrogenated ta-C (ta-C:H) are considerably lower than those of ta-C because of the weakening effect of C-H bonding.

scholarly journals Elastic Constants of Nanometer Thick Diamond-like Carbon Films

2001 ◽  
Vol 675 ◽  
Author(s):  
Marco G. Beghi ◽  
Carlo E. Bottani ◽  
Andrea LiBassi ◽  
Rosanna Pastorelli ◽  
Brian K. Tanner ◽  
...  
Keyword(s):  
Thick Film ◽  
Amorphous Carbon ◽  
Elastic Constants ◽  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
Carbon Films ◽  
Dispersion Relations ◽  
Elastic Model ◽  
Amorphous Carbon Films ◽  
Tetrahedral Amorphous Carbon

ABSTRACTCarbon films of thickness down to 2 nanometers are necessary to achieve a storage density of 100 Gbit/in2 in magnetic hard disks. Reliable methods to measure the properties of these ultrathin films still have to be developed. We show for the first time that combining Surface Brillouin Scattering (SBS) and X-ray reflectivity measurements the elastic constants of such films can be obtained. Tetrahedral amorphous carbon films were deposited on silicon, by an S bend filtered cathodic vacuum arc, which provides a continuous coverage on large areas free of macroparticles. Films of thickness down to 2 nm and density of ∼3 g/cm3 were produced and characterized. The dispersion relations of surface acoustic waves are measured by SBS for films of different thickness and for the bare substrate. Waves can be described by a continuum elastic model. Fitting of the dispersion relations, computed for given film properties, to the measured dispersion relations allows the derivation of the elastic constants. Fora 8 nm thick film we find a Young's modulus E around 400 GPa, with a shear modulus G lying in the 130 – 210 GPa interval. For a 4.5 nm thick film, E is around 240 GPa, with G lying in the 70 – 130 GPa interval. Results for even thinner films become highly sensitive to the precision of the substrate properties, and indicate that the above values are lower bounds. We thus show that we can grow and characterize nanometer size tetrahedral amorphous carbon films, which maintain their density and mechanical properties down to the nm range.

Ultraviolet and visible Raman studies of nitrogenated tetrahedral amorphous carbon films

2000 ◽  
Vol 366 (1-2) ◽  
pp. 169-174 ◽  
Author(s):  
J.R. Shi ◽  
X. Shi ◽  
Z. Sun ◽  
E. Liu ◽  
B.K. Tay ◽  
...  
Keyword(s):  
Amorphous Carbon ◽  
Carbon Films ◽  
Amorphous Carbon Films ◽  
Tetrahedral Amorphous Carbon
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