Strongly adhering and thick highly tetrahedral amorphous carbon (ta–C) thin films via surface modification by implantation

2001 ◽  
Vol 16 (1) ◽  
pp. 5-8 ◽  
Author(s):  
M. Chhowalla ◽  
G. A. J. Amaratunga
Keyword(s):  
Thin Films ◽  
Amorphous Carbon ◽  
Ion Bombardment ◽  
Vacuum Arc ◽  
Growth Surface ◽  
Simple Modification ◽  
Metallic Substrates ◽  
Tetrahedral Amorphous Carbon ◽  
Protective Overcoats ◽  
Poor Adhesion

Highly tetrahedral amorphous carbon thin films have exceptional mechanical properties that make them ideal for many challenging wear applications such as protective overcoats for orthopaedic prostheses and aerospace components. However, the use of ta–C in many wear applications is limited due to the poor adhesion and the inability to grow thick films because of the large compressive stress. Here we report on a simple modification of the substrate growth surface by 1-keV ion bombardment using a cathodic vacuum arc (CVA) plasma prior to deposition of ta–C films at 100 eV. The 1-keV C+ ion bombardment created a thin intermixed layer consisting of substrate and carbon atoms. The generation of the intermixed carbide layer improved the adhesion and allowed the growth of thick (several μm) ta–C layers on metallic substrates.

X-RAY REFLECTIVITY STUDY OF TETRAHEDRAL AMORPHOUS CARBON FILMS

2000 ◽  
Vol 14 (02n03) ◽  
pp. 181-187 ◽  
Author(s):  
B. K. Tay ◽  
X. Shi ◽  
S. P. Lau ◽  
Q. Zhang ◽  
H. C. Chua ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Amorphous Carbon ◽  
Mass Density ◽  
Ion Bombardment ◽  
Carbon Films ◽  
Vacuum Arc ◽  
Amorphous Carbon Films ◽  
X Ray ◽  
Tetrahedral Amorphous Carbon ◽  
Bombardment Energy

Hydrogen-free amorphous carbon films were deposited at different deposition bais voltage on a single silicon wafer by a process known as Filtered Cathodic Vacuum Arc (FCVA). The influences of different deposition bias voltages on the microstructure and the properties of thin tetrahedral amorphous carbon (ta-C) films, such as surface roughness, film mass density and thickness, have been studied by means of the x-ray reflectivity technique (XRR) for the first time. The microstructure of these films deposited on silicon wafers was stimulated by a four-layer model consisting of a ta-C layer, a mixed ta-C:Si layer, Si-O layer and the silicon subtrate. The mixed ta-C:Si layer consisting of the mixture of ta-C and silicon simulates the carbon ion impinging / diffusion into the surface of the silicon substrate. The mass density and the roughness of the film are found to be dependent on the impinging ion bombardment energy. The mass density increases with increase in ion bombardment energy up to 100 eV. Beyond 100 eV, the mass density decreases with further increase in ion bombardment energy up to 100 eV. Beyond 100 EV, the mass density decreases with further increase in ion bombardment energy. The surface roughness decreases with increasing ion bambardment energy to a minimum value at 100 eV, after which it increases with further increase in ion bombardment energy. The thickness of the films obtained by XRR technique correlates well with the thickness measurement obtained by spectral reflectometry. The existence of the Si-O layer was verified by Auger depth profiling.

FCVA-Synthesized Tetrahedral Amorphous Carbon Films for Biomedical Applications

2007 ◽  
Vol 336-338 ◽  
pp. 1577-1580 ◽  
Author(s):  
Chuan Lin Zheng ◽  
Wu Bao Yang ◽  
X. Chang
Keyword(s):  
Amorphous Carbon ◽  
Biomedical Applications ◽  
Pure Titanium ◽  
Carbon Films ◽  
Vacuum Arc ◽  
Negative Bias Voltage ◽  
Tetrahedral Amorphous Carbon ◽  
In Vitro Measurements ◽  
Filtered Cathodic Vacuum Arc

Tetrahedral amorphous carbon (ta-C) films were deposited onto Si(100) wafers by using filtered cathodic vacuum arc technique (FCVA). The influence of the negative bias voltage applied to substrates on film structures was studied by Raman spectroscopy, X-ray photoemission spectroscopy (XPS). The ta-C films showed maximal sp3 fractions 87%, the hardness and elastic modulus of the ta-C film is 72 and 480 GPa, respectively. In vitro measurements of contact angle and platelet adhesion were applied to evaluate the biocompatibility of the ta-C films in comparison with that of NiTi, 316L and pure titanium. The results show that the ta-C films have hydrophobicity and exhibit better hemocompatibility which are very suitable for biomedical applications.

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.

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