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.

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

Tribological Propertees of Carbon thin Films Prepared by Plasma-Free Sputtering Method

1991 ◽  
Vol 239 ◽  
Author(s):  
T. Hirata ◽  
M. Naoe
Keyword(s):  
Thin Films ◽  
Low Temperature ◽  
Magnetron Sputtering ◽  
Amorphous Carbon ◽  
Carbon Films ◽  
Diamond Like Carbon ◽  
Amorphous Carbon Films ◽  
Magnetic Disk ◽  
Protective Layers ◽  
Better Than

ABSTRACTAmorphous “Diamond-like” carbon films were deposited on plasma-free substrates at low temperature by the Facing Targets Sputtering (FTS) method. Tribological characteristics determined by tap, scratch and slide tests were much better than those for amorphous carbon films deposited by the conventional Magnetron Sputtering (MS) method. Consequently, these films deposited by the FTS method were surely useful for protective layers in rigid magnetic disk.

Tetrahedral Amorphous Carbon With Ultratrace Hydrogen

2014 ◽  
Author(s):  
Hiroshi Inaba ◽  
Toru Matsumura ◽  
Yoko Saito ◽  
Hiroyuki Matsumoto
Keyword(s):  
Amorphous Carbon ◽  
Near Field ◽  
Carbon Films ◽  
Diamond Like Carbon ◽  
Protective Film ◽  
Amorphous Films ◽  
Amorphous Carbon Films ◽  
Tetrahedral Amorphous Carbon ◽  
Crystalline Films ◽  
Heating Up

In heat assisted magnetic recording (HAMR) where near-field light from a head heats up a disk, disk overcoat needs to be heat-resistive and transparent. ta-C (tetrahedral amorphous carbon) films have been considered to be promising for HAMR disk overcoat, because they are denser and harder than diamond-like carbon (DLC) films that have been used as disk overcoat. In the previous study, ta-C did not show any change in the film thickness by heating up to 450 degrees Celsius, approving a heat-resistant high protective film [1]. The purpose of this study is to investigate enhanced ta-C, which is harder, denser and higher-thermostability than those of conventional ta-C in reference to that nanometer-sized diamonds were more stable than graphite by adding the small amount of hydrogen [2]. In this report, ultratrace hydrogenerated ta-C, amorphous films, was investigated to expect similar effect as was observed in the crystalline films.

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