Structural Stability of Si-O-a-C:H/Si-a-C:H Layered Systems

AbstractAmorphous hydrogenated carbon films are of technological interest as protection coatings due to their special properties such as high hardness, chemical inertness, electrical insulation and infrared transparency. However, some applications still suffer from the poor thermal stability and adhesion problems of these coatings. To ensure good adhesion, especially on hardened steels and non-carbide forming substrates, an extra interlayer has to be deposited first. Often a silicon containing interlayer, Si-a-C:H for example, is used for this purpose. This Si-a-C:H interface layer was deposited by rf plasma deposition from tetramethylsilane. Then a-C:H films containing Si-O with a varying silicon content were produced from a mixture of acetylene and hexamethyldisiloxane. The structural changes upon annealing of these films were investigated using Raman spectroscopy. The analysis of the development of the different peaks upon annealing temperature reveals the transition from the amorphous structure to the more graphitic-like structure. This transition temperature increases by as much as 100°C when silicon is incorporated into the DLC film. However, when Si-O is incorporated instead of only silicon the same increase in temperature stability is observed.

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Precision Coating of ta-C Films on Quartz Surfaces

JSME 2020 Conference on Leading Edge Manufacturing/Materials and Processing ◽

10.1115/lemp2020-8589 ◽

2020 ◽

Author(s):

Kotaro Kawai ◽

Yuki Hirata ◽

Hiroki Akasaka ◽

Naoto Ohtake

Keyword(s):

Cutting Tools ◽

Three Dimensional ◽

High Hardness ◽

Carbon Films ◽

Vacuum Arc ◽

High Wear Resistance ◽

Chemical Inertness ◽

Filtered Cathodic Vacuum Arc ◽

Surface Morphologies

Abstract Diamond-like carbon (DLC) films have excellent properties such as high hardness, low friction coefficient, high wear resistance, chemical inertness and so on. Because DLC film is considered as an effective coating material to improve their surface properties, this films are used in various applications such as parts for automobiles engines, hard disk surfaces, cutting tools and dies, and so on. DLC films consist of a mixture of sp2 bonded carbon atoms and sp3 bonded carbon atoms. Among them, ta-C film is known as the hardest and strongest film since it mainly consists of sp3 bonded carbon atoms. One of deposition methods to form ta-C is Filtered Cathodic Vacuum Arc (FCVA). The characteristic of this method is that it is possible to remove the droplets and form a high-quality film.. However, even though lots of mechanical components which require ta-C coating have three-dimensionally shapes, it is difficult to coat ta-C film three dimensionally by using FCVA process. At present, researches on 3D deposition of amorphous carbon films on three dimensional components is still insufficient, and investigation reports on the deposition mechanism and characterization of the deposited films are even more limited. In this study, we tried to deposit films on 3D components by the FCVA method and evaluated the microstructure and surface morphologies of films. Although films were coated successfully in the entire surfaces, different properties were showed depending on the location of components. These properties were investigated by Raman spectroscopy and laser microscope.

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Fluctuation Microscopy Studies of Amorphous Diamond-Like Carbon Films

Microscopy and Microanalysis ◽

10.1017/s1431927600034656 ◽

2000 ◽

Vol 6 (S2) ◽

pp. 432-433

Author(s):

X. Chen ◽

J. M. Gibson ◽

J. Sullivan

Keyword(s):

Electronic Devices ◽

High Hardness ◽

Carbon Films ◽

Optical Coatings ◽

Diamond Like Carbon ◽

Electron Loss ◽

Negative Electron Affinity ◽

Chemical Inertness ◽

Potential Applications ◽

Key Questions

Hydrogen-free amorphous diamond-like carbon films have stimulated great interest because of their useful properties, such as high hardness, chemical inertness, thermal stability, wide optical gap, and negative electron affinity[l]. Consequently, they may have various potential applications in mechanical and optical coatings, MEMS systems, chemical sensors and electronic devices. Amorphous diamond-like carbon films often contains significant amounts of four-fold or sp3 bonded carbon, in contrast to amorphous carbon films prepared by evaporation or sputtering which consist mostly of three-fold or sp2 bonded carbon. The ratio and the structure configurations of these three-fold and four-fold carbon atoms certainly decide the properties of these amorphous diamond-carbon films. Although the ratio of three-fold and four-fold carbon has been studied with Raman spectroscopy and electron-loss-energy spectroscopy, very little has been understood regarding key questions such as how the three-fold and the four-fold carbon atoms are integrated in the film, and what structures those three-fold carbon atoms take.

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Some optical properties of amorphous hydrogenated carbon thin films prepared by rf plasma deposition using methane

Microelectronics Journal ◽

10.1016/s0026-2692(01)00046-5 ◽

2001 ◽

Vol 32 (9) ◽

pp. 783-786 ◽

Cited By ~ 4

Author(s):

Marco A.R. Alves ◽

Jônatas F. Rossetto ◽

Olga Balachova ◽

Edmundo da Silva Braga ◽

Lucila Cescato

Keyword(s):

Thin Films ◽

Optical Properties ◽

Plasma Deposition ◽

Rf Plasma ◽

Carbon Thin Films ◽

Amorphous Hydrogenated Carbon

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Annealing effects in amorphous hydrogenated carbon films prepared by plasma deposition from butane gas

phys stat sol (a) ◽

10.1002/pssa.2210950131 ◽

1986 ◽

Vol 95 (1) ◽

pp. 249-254 ◽

Cited By ~ 6

Author(s):

K. Yasuda ◽

H. Masuda ◽

M. Takeda ◽

A. Yoshida

Keyword(s):

Plasma Deposition ◽

Carbon Films ◽

Annealing Effects ◽

Amorphous Hydrogenated Carbon

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Temperature stability of fluorinated amorphous hydrogenated carbon films

Surface and Coatings Technology ◽

10.1016/0257-8972(95)02560-x ◽

1995 ◽

Vol 76-77 ◽

pp. 367-371 ◽

Cited By ~ 26

Author(s):

U. Müller ◽

R. Hauert ◽

B. Oral ◽

M. Tobler

Keyword(s):

Temperature Stability ◽

Carbon Films ◽

Amorphous Hydrogenated Carbon

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Preparation and Characterization of Chromium Containing amorphous Hydrogenated Carbon Films (A-C:H/Cr)

MRS Proceedings ◽

10.1557/proc-388-305 ◽

1995 ◽

Vol 388 ◽

Cited By ~ 5

Author(s):

R. Gampp ◽

P. Gantenbein ◽

P. Oelhafen

Keyword(s):

Chromium Carbide ◽

Photoelectron Spectroscopy ◽

Chemical Vapor ◽

Carbon Films ◽

Rf Plasma ◽

Silicon Substrates ◽

Amorphous Hydrogenated Carbon ◽

High Chemical Stability

AbstractChromium containing amorphous hydrogenated carbon films (a-C:H/Cr) were prepared in a process that combines rf plasma activated chemical vapor deposition of methane and magnetron sputtering of a chromium target. During the deposition the silicon substrates were kept at 200°C and dc biased at -200 V in order to obtain films with high chemical stability which is required for the application as solar selective surfaces. the films with different Cr concentrations (5 to 49 at.%) were characterized by in situ x-ray photoelectron spectroscopy (XPS). Up to 40 at.%, chromium proves to be built into the cermet-like films in the form of chromium carbide clusters. above 40 at.%, chromium is partly metallic. a modification of the a-C:H matrix in the vicinity of the chromium carbide clusters has been observed.

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A Study on the Residual Stress of Diamond-Like Carbon Films Deposited by Magnetically Enhanced RF PECVD

MRS Proceedings ◽

10.1557/proc-441-671 ◽

1996 ◽

Vol 441 ◽

Cited By ~ 2

Author(s):

Woon Choi ◽

Dong-Hoon Shin ◽

Seoung-Eui Nam ◽

Hyoung-June Kim

Keyword(s):

Plasma Deposition ◽

Flux Ratio ◽

Carbon Films ◽

Film Stress ◽

Stress Generation ◽

Rf Plasma ◽

Process Conditions ◽

Working Pressure ◽

Rapid Reduction ◽

Ion Energy

AbstractHydrogenated DLC films were synthesized by RF plasma deposition with and without magnetic enhancement, and their film stresses were investigated as a function of process parameters. Under investigated process conditions, Vb/P1/2 (where Vb is the self-bias voltage and P is the working pressure) is the appropriate scaling factor representing impinging ion energy. Film stress is influenced by not only ion impinging energy but also by ion to adspecies flux ratios. As ion energy increases, film stresses increase to a maximum value corresponding to the highest number of sp3 carbon bonds. As ion/adspecies flux ratio increases, the maximum stress value decreases and the corresponding ion energy increases. Induction of a magnetic field promotes film stresses as high as 15.2 GPa, which is one of the highest value reported in hydrogenated DLC films. The magnetic-induced increase of stress can be explained by increased ion/adspecies flux ratio, thus, enhanced sp3 formation. Rapid reduction of stresses observed at high ion energies may stem from the formation of graphite (sp2 bond) phases. Inclusion of hydrogen in the films is not directly responsible for the stress generation.

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