Effects of post-deposition annealing on different DLC films

Wächter, R.; Cordery, A.

doi:10.1016/s0925-9635(98)00395-1

Cited by 35 publications

(15 citation statements)

References 22 publications

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“…As the temperature is increased, the structure of DLC films, which is claimed to be a metastable form of carbon with mixture of sp 3 /sp 2 bonds [1,2] , collapses into a more sp 2 -bonded network by a sp 3 diamond-like domains conversion. This instability, denominated as graphitization process, is extremely noticeable in the one of the major DLC family, the H-containing form of amorphous carbon (a-C:H) [3][4][5][6][7][8][9][10][11] . It is well known that hydrogen stabilizes the diamond structure by maintaining the sp 3 hybridization configuration.…”

Section: Introductionmentioning

confidence: 99%

Thermal stability in oxidative and protective environments of a-C:H cap layer on a functional gradient coating

Louro

Moura²,

Carvalho

et al. 2011

Diamond and Related Materials

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Three types of hydrogenated amorphous carbon (a-C:H) coatings were synthesized on stainless steel substrates by a Plasma Assisted CVD process, containing hydrogen contents in the range from 25 to 29 at.%. The effect of annealing up to 600 ºC in two different environments on both the structure and the mechanical properties of the coatings was investigated by means of Differential Scanning Calorimetry/Thermogravimetry (DCS/TG), Raman Spectroscopy and Depth Sensing Indentation. The results indicate that the structural modifications occurred in the coatings in both protective and oxidative atmospheres up to 400ºC were due to a complex atomic rearrangement involving the dehydrogenation reaction. A small weight loss, detected by isothermal TG analysis confirmed the H 2 effusion. This dense effect proceeds without a change of hardness which was maintained in the diamond-like regime. The annealing in non-oxidative ambiance at temperatures above 500ºC causes both gaseous products effusion and sp 3 to sp 2 transformation. Raman parameters and hardness values were, under these conditions, similar to those known for a typical graphite-like regime. While the onset temperature of the graphitization process was found to be almost independent of the H content range investigated, the situation was completely different inrelation to the oxidation reaction. The highest oxidation resistance was found for coatings with the lowest H content.

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Section: Introductionmentioning

confidence: 99%

Thermal stability in oxidative and protective environments of a-C:H cap layer on a functional gradient coating

Louro

Moura²,

Carvalho

et al. 2011

Diamond and Related Materials

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“…In nanosecond laser processing, thermal gradient parallel to the interface was less than perpendicular gradient by orders of magnitude due to a small thermal diffusion distance and large dimensions of the laser beam as compared to the thickness of a melted DLC layer. This quasi-stationary laser annealing [6] is a one-dimensional problem, in which the structural transformations of a-C:H films depend on temperature, decreasing from the surface towards the bulk. Thus, the laser-modified surface layer appears to be non-uniform in depth.…”

Section: Introductionmentioning

confidence: 99%

Modification of amorphous a-C:H films by laser irradiation

Grigonis¹

2007

Lithuanian J. Phys.

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Amorphous diamond-like hydrogenated carbon films a-C:H were formed on Si wafers by a direct ion beam deposition method from acetylene or a gas mixture of acetylene and hydrogen. The samples were irradiated in a scanning mode by second harmonic (wavelength λ = 532 nm) of a Q-switched YAG : Nd laser. The effect of laser irradiation was studied by Raman and infrared spectroscopy and spectroscopic ellipsometry. The changes in the optical spectra of the samples with different H amount were investigated in the dependence on laser intensity. Experimental data were interpreted taking into account the structural transformations of a-C:H films.

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“…26,27) Table 2 also implies that the DLCH is more stable and has slight graphitization when heating up to 300 C. This critical temperature is in agreement with the study that thermal annealing treatment would result in the conversion from amorphous carbon into graphite and soften the DLCH structure. [7][8][9] …”

Section: Contact Angle Testmentioning

confidence: 99%

“…The combination of PI's residual tensile stress and thermal annealing relief effect on DLCH film can partially release some DLCH's residual compressive stress. [7][8][9] Adhesion strength can be evaluated by using the crosscut tool and tape test method. The results show a white and small area, which indicates the crosscut paths for remained DLCH surface due to PI film have been scratched out.…”

Section: Residual Stressmentioning

confidence: 99%

“…However, such treatments will cause hardness significantly decreasing when annealed temperature is above certain critical transition point. [7][8][9] Other methods use the additive layer under the DLCH film, such as the interlayer structure (DLCH/Ti/substrate), multilayer structure (DLCH/TiCN/TiN/Ti/substrate) and special graded structure to improve the DLCH adhesion. 10) In addition, many studies have been reported about the property in DLCH over polymer structure.…”

Section: Introductionmentioning

confidence: 99%

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Spin-Coating Polyimide Film on Hydrogenated DLC Film Surface Prepared by Ion Beam Deposition Method

2006

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The present work describes the hybrid layers consisting of 1-mm-thick hydrogenated diamond-like carbon (DLCH) film deposited by ion beam deposition (IBD) method as the bottom layer and spin coating polyimide (PI) film at a thickness of 6 mm as the top layer. Optical microscopy shows that all DLCH film, PI film and PI/DLCH film have smooth surface and are free from cracks or wrinkles. Water contact angle measurement shows that the annealed DLCH film has the higher relative adhesive tension and adhesive work than that of PI film. Raman spectra show that the DLCH film can avoid severe graphitization & degradation at 300 C during annealing treatment, and FTIR spectra also exhibit that the PI film will reach 95% imidization during the curing step at 300 C. PI film can act on DLCH film as the stress buffer. This is demonstrate from warpage measurement showing that top PI film with tensile stress can partially reduce the compressive stress over bottom DLCH film with 6.7% warpage reduction. The electrical resistivity of PI/DLCH/Si is similar to that of PI/Si is resulted from the PI passivation effect.

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Effects of post-deposition annealing on different DLC films

Cited by 35 publications

References 22 publications

Thermal stability in oxidative and protective environments of a-C:H cap layer on a functional gradient coating

Thermal stability in oxidative and protective environments of a-C:H cap layer on a functional gradient coating

Modification of amorphous a-C:H films by laser irradiation

Spin-Coating Polyimide Film on Hydrogenated DLC Film Surface Prepared by Ion Beam Deposition Method

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