Iron, nitrogen and silicon doped diamond like carbon (DLC) thin films: A comparative study

doi:10.1016/j.tsf.2016.04.048

Thin Solid Films

Volume 610, 1 July 2016, Pages 42-47

https://doi.org/10.1016/j.tsf.2016.04.048 Get rights and content

Highlights

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Fe, N and Si doped DLC films deposited by dip, PLD and PECVD methods respectively
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DLC:Fe thin films have higher hardness/Young's modulus than DLC:N(:Si) thin films.
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sp³ and sp² contents are estimated from C K-edge XANES and VB-PES measurements.

Abstract

The X-ray absorption near edge structure (XANES), X-ray photoelectron spectroscopy (XPS), valence band photoemission (VB-PES) and Raman spectroscopy results show that the incorporation of nitrogen in pulsed laser deposited diamond like carbon (DLC) thin films, reverts the sp³ network to sp² as evidenced by an increase of the sp² cluster and I_D/I_G ratio in C K-edge XANES and Raman spectra respectively which reduces the hardness/Young's modulus into the film network. Si-doped DLC film deposited in a plasma enhanced chemical vapour deposition process reduces the sp² cluster and I_D/I_G ratio that causes the decrease of hardness/Young's modulus of the film structure. The Fe-doped DLC films deposited by dip coating technique increase the hardness/Young's modulus with an increase of sp³-content in DLC film structure.

Introduction

Diamond-like carbon (DLC) coatings have been the subject of intensive studies for the last more than 35 years. The general term DLC describes hydrogenated and non-hydrogenated carbon materials prepared by a variety of methods and presenting a wide range of structure, composition and properties, such as low friction, high wear resistance, chemical inertness, a relatively high optical gap and high electrical resistivity [1]. The DLC films contain significant fractions of sp³ type carbon bonds, giving them attractive physical and mechanical properties that are, to a certain extent, similar to diamond. DLC films present a noteworthy example of thin films whose tribological behaviour strongly depends both on the nature of the coating and the testing conditions, including mechanical, physical and chemical parameters; which in turn depend on the technique used for film deposition [1]. The nature and properties of the DLC can also be modified by controlling the incorporation of dopants, such as silicon, fluorine, nitrogen and various metals. Silicon incorporation in the DLC structure is recognized to affect most of the film properties, including a decrease of the surface energy and internal stress, and the tribological behaviour. Friction appears to be significantly reduced compared to conventional undoped DLC in ambient humid air, with a comparable high wear resistance. Therefore, DLC:Si films may be used in applications requiring both low friction and high wear resistance under moderate mechanical conditions, for the protection of low-stress aerospace or automotive components, precision ball bearings and gears, sliding bearings and magnetic recording media. The metal-containing DLC coating films may exhibit promising tribological properties in terms of steady-state friction level and wear rates for many applications. The effect of nitrogen doping DLC film shows the opposite effect on the surface energy than the silicon-doping and even stress also reduced [2]. However, it was reported that doping of non-metal, such as nitrogen (N) resulted in the enhanced adhesion strength of DLC films by increasing sp² bonds and subsequently relaxing residual stress in the films [1]. In addition, the tribological performance of DLC films can be improved by N-doping because the incorporation of N in DLC films promotes the graphitization of the films and reduces the friction of the films via the enhanced lubricating effect [3]. These carbon-based multi-component DLC films may be combined to obtain property-controlled multilayer coatings and could be used in protective and coating technology. The DLC also can be used as an antireflective and scratch-resistant wear-protective coating for IR optics [4]. The low deposition temperatures of DLC allows its use as a wear-protective layer on products made of plastic and is therefore used for protection against abrasion of sunglass lenses made of polycarbonate [5]. The most widespread use of DLC films is in wear and corrosion protection of magnetic storage media [6]. Nano-smooth and very thin (< 50 nm and even < 10 nm) DLC films are used as corrosion and wear-protective coatings for both the magnetic disks and the magnetic heads. Tapes for video recording or magnetic data storage, using ferromagnetic metal as a recording media as well as the metallic capstans in contact with the tapes, are also being protected with DLC coatings to reduce wear and friction, thus extending the life of the tapes and their reliability [6].

The present work deals with the three sets of undoped/doped incorporation of silicon, iron-metal and nitrogen–DLC thin films deposited at three different processes with almost similar quantification ratios [Fe / (Fe + C) = 0.11, Si / (Si + C) = 0.10 and N / (N + C) = 0.13] to understand the electronic structure/bonding properties and hence their hardness for the application in different coating-technologies to increase the lifetime of different DLC coated articles. A similar dopant ratio is considered to compare the differences of effect in each set of DLC thin films prepared at three different deposition processes.

Section snippets

Experimental details

Three sets of undoped/doped thin films were characterized and compared in each set of thin films for their electronic and bonding structure by the measurements of X-ray absorption near edge structure (XANES), valence band photoemission (VB-PES) and Raman spectroscopy. The hardness/Young's modulus was measured using a Nano-indenter XP (Nano Instruments). The C K-edge XANES and VB-PES measurements of these films were performed at the National Synchrotron Radiation Research Centre (NSRRC),

Results and discussion

Fig. 1(a–c) shows the normalized C K-edge XANES spectra of DLC and DLC:Fe (:N, :Si) thin films. Fig. 1(a) shows the positions of π* and σ* resonance features of DLC1 and DLC1:Fe at near ~ 284.9 (± 1) eV and ~ 292.6 (± 1) eV, which were observed by other researchers for carbon related material [11], [12], [13]. The π* feature at ~ 284.9 eV is typical of the C double bond C bond (sp²), while the σ* band feature at ~ 292.6 eV is typical of the tetrahedral C single bond C bond (sp³) [14], [15], [16]. Two additional peaks near 286.6

Conclusion

In conclusion, the study of electronic/micro-structural and mechanical properties of Fe, N and Si-doped alloying DLC thin films is very useful for different coating, protective, and adhesive applications. The nano-indentation measurement shows that the hardness of DLC1 is increased upon Fe doping. This DLC1:Fe is more effective in achieving the wear-durable, nonconductive film and very useful as tool coating and nano-devices due to its hardness and good adhesion. In DLC1 films with metal (Fe)

Acknowledgements

The author S.C.R. acknowledges the National Research Foundation, South Africa (Grant No. EQP13091742446) for financial support.

References (41)

J. Robertson
Diamond-like amorphous carbon
Mater. Sci. Eng.
(2002)
C. Donnet
Recent progress on the tribology of doped diamond-like and carbon alloy coatings: a review
Surf. Coat. Technol.
(1998)
F.M. Kimock et al.
Commercial applications of ion beam deposited diamond-like carbon (DLC) coatings
Surf. Coat. Technol.
(1993)
S.C. Ray et al.
Electronic and bonding properties of Fe- and Ni based hydrogenated amorphous carbon thin films by X-ray absorption, valence-band photoemission and Raman spectroscopy
Diam. Relat. Mater.
(2011)
P. Papakonstantinou et al.
The effects of Si incorporation on the electrochemical and nanomechanical properties of DLC thin films
Diam. Relat. Mater.
(2002)
S.C. Ray et al.
Orientation of graphitic planes during annealing of “dip deposited” amorphous carbon film: a carbon K-edge X-ray absorption near-edge study
Carbon
(2006)
I. Ahmad et al.
Substrate effects on the microstructure of hydrogenated amorphous carbon films
Curr. Appl. Phys.
(2009)
N. Benchikh et al.
Nickel-incorporated amorphous carbon film deposited by femtosecond pulsed laser ablation
Thin Solid Films
(2005)
C. Ziethen et al.
Soft X-ray photoelectron microscopy used for the characterization of diamond, a-C and CNx, thin films
Diam. Relat. Mater.
(2002)
J.S. Chen et al.
Metal-containing amorphous carbon films for hydrophobic application
Thin Solid Films
(2001)

C. Corbella et al.

Structure of diamond-like carbon films containing transition metals deposited by reactive magnetron sputtering

Diam. Relat. Mater.

(2005)

J. Wang et al.

Tailoring the structure and property of silicon-doped diamond-like carbon films by controlling the silicon content

Surf. Coat. Technol.

(2013)

Q. Zhao et al.

Bacterial adhesion on silicon-doped diamond-like carbon films

Diam. Relat. Mater.

(2007)

W.J. Gammon et al.

Hard and elastic amorphous carbon nitride thin films studied by ¹³C nuclear magnetic resonance spectroscopy

Phys. Rev. B

(2002)

P. Koidl et al.

Hard carbon coating for IR-optical components

Proc. SPIE Optic. Surf. Technol.

(1983)

A.C. Ferrari, Diamond-like carbon for magnetic storage disks, Surf. Coat. Technol. 180–181 (2004)...

R. McCann et al.

Spectroscopic analysis of a-C and a-CN_x films prepared by ultrafast high repetition rate pulsed laser deposition

J. Appl. Phys.

(2005)

S.C. Ray et al.

Electronic structure and bonding properties of Si-doped hydrogenated amorphous carbon films

Appl. Phys. Lett.

(2004)

S.C. Ray et al.

X-ray absorption spectroscopy (XAS) study of dip deposited a-C:H(OH) thin films

J. Phys. Condens. Matter

(2004)

S. Anders et al.

Thermal stability of amorphous hard carbon films produced by cathodic arc deposition

Appl. Phys. Lett.

(1997)

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Iron, nitrogen and silicon doped diamond like carbon (DLC) thin films: A comparative study

Highlights

Abstract

Introduction

Section snippets

Experimental details

Results and discussion

Conclusion

Acknowledgements

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Surf. Coat. Technol.

Surf. Coat. Technol.

Diam. Relat. Mater.

Diam. Relat. Mater.

Carbon

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Surf. Coat. Technol.

Diam. Relat. Mater.

Hard and elastic amorphous carbon nitride thin films studied by 13C nuclear magnetic resonance spectroscopy

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Hard carbon coating for IR-optical components

Proc. SPIE Optic. Surf. Technol.

Spectroscopic analysis of a-C and a-CNx films prepared by ultrafast high repetition rate pulsed laser deposition

J. Appl. Phys.

Electronic structure and bonding properties of Si-doped hydrogenated amorphous carbon films

Appl. Phys. Lett.

X-ray absorption spectroscopy (XAS) study of dip deposited a-C:H(OH) thin films

J. Phys. Condens. Matter

Thermal stability of amorphous hard carbon films produced by cathodic arc deposition

Appl. Phys. Lett.

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