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Diamond like carbon Muresan Mihai. Carbon Carbon is the fourth most abundant chemical element in the universe by mass The structures of eight allotropes.

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Presentation on theme: "Diamond like carbon Muresan Mihai. Carbon Carbon is the fourth most abundant chemical element in the universe by mass The structures of eight allotropes."— Presentation transcript:

1 Diamond like carbon Muresan Mihai

2 Carbon Carbon is the fourth most abundant chemical element in the universe by mass The structures of eight allotropes of carbon: a) Diamond b) Graphite c) Lonsdaleite d) C60 Fullerene e) C540 Fullerene f) C70 Fullerene g) Amorphous carbon h) SWCNT

3 Carbon Diamond – the hardest naturally occurring substance Graphite – the cheapest fuel (coal), electrical conductor, heat resistant material and lubricant Fullerenes – potential medical use CNT – strongest and stiffest material, possible high electric conductivity, composite polymers, ultracapacitors Graphene – ballistic electrical conductivity, gas detectors, IC, biodevices a-C – a material that is not diamond or graphite

4 a-C a-C:H can be split in four types: 1.polymer-like a-C:H (PLCH) with the highest H content (40–60%), but soft 2.harder diamond-like a-C:H (DLCH) with intermediate H content (20– 40 at. %), 3.hydrogenated tetrahedral amorphous carbon films (ta-C:H) with fixed H content 25–30 at. % H 4.graphite-like a-C:H with less than 20 at. % of H

5 a-C:H properties  High thermal conductivity  High hardness  Good abrasion coefficient  Low friction coefficient  Gas barrier  Inertness  Wide band gaps

6 a-C problems Bad adhesion (especially on metals) High stressed films Thermal stability under 300 O C (a-C:H) Solving the problems:  Fabrication of intermediate metallic layer  Intermediate compound layer (WC, TiC)  Doping with different elements

7 DLC uses

8 a-C and hard films production 782 mil $ 905 mil $ 1.7 bn $ Arc discharge Magnetron sputtering

9 Why PECVD? Relatively easy to produce plasma Pure deposition due to low pressure Large size depositions Precision of the coating Low melting point substrates Good dielectric properties

10 PECVD System

11 PECVD system PECVD deposition CCP RF MHz Vacuum system (~10 -4 Pa) Gas flow meters 420 mm electrode

12 PECVD chemistry

13 Types of DLC films DLC from CH 4, H 2 DLC:N with N 2 DLC:SiO x with HMDSO/HMDSZ Deposition at room temperature Low cost Relative big substrates

14 Why DLC:N films?

15 Preparation of DLC films

16 Characterization of DLC films ellipsometry - Jobin Yvon UVISEL nm reflectometry - Perkin Elmer Lambda nm FTIR transmittance - Bruker Vertex 80v cm -1 correct transmittance accessory depth sensing indentation - Fischerscope H100 with Vickers indenter ion beam spectroscopies - Rutherford Backscattering Spectroscopy (RBS) and Elastic Recoil Detection Analysis (ERDA)

17 Optical characterization

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20 Mechanical characterization

21 Chemical composition Ar content below 0.3%

22 a-C:H:SiO x films

23 Conclusions Hard DLC films can be produced on low melting point substrates DLC:N films can be used on metallic substrates DLC:SiOx films present higher thermal stability o The method is relatively cheap, can cover large substrates and can be employed for low melting point substrates (plastics)

24 Thank you for your attention


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