Low-pressure diamond: from the unbelievable to technical products

AbstractThe idea to grow diamond from the gas phase was born in the 1950s but it took about 30 years until first diamond layers directly grown from the gas phase on substrates were shown in Japan by Matsumoto and co-workers. During the first years of research the function of atomic hydrogen, various growth methods and process parameters were investigated. Research was primarily focused on applications for wear-resistant tools. For this topic the interactions of substrates like hardmetals and ceramics, with diamond deposition gas atmosphere, were investigated. Beside its superior hardness, diamond exhibits the highest heat conductivity, high transparency, high chemical inertness and suitable semiconducting properties. The various requirements for the areas of application of diamond required a division of diamond research into corresponding sub-areas. The hot-filament method is used mainly for wear applications, because it is highly suited to coat complex geometries, but the diamond contains some impurities. Another method is the microwave plasma system which allows the growth of pure diamond used for optical windows and applications requiring high thermal conductivity. Other research areas investigated include doped diamond for microelectronic or electrochemical applications (e.g. waste water treatment); ballas (polycrystalline, spherical diamond), NCD (nanocrystalline diamond) and UNCD (ultra-nanocrystalline diamond) for wear applications.It should be noted that CVD (chemical vapour deposition) diamond synthesis has reached the stage of industrial production and several companies are selling different diamond products. This work is intended to convey to the reader that CVD diamond is an industrially manufactured product that can be used in many ways. With correspondingly low costs for this diamond, new innovative applications appear possible.

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Evaluation of Wear Rate of Nanocrystalline Diamond Films Using Abbott Curve

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.267.185 ◽

2017 ◽

Vol 267 ◽

pp. 185-189

Author(s):

Andrei Bogatov ◽

Vitali Podgursky

Keyword(s):

Wear Rate ◽

Cross Sections ◽

Vapour Deposition ◽

Microwave Plasma ◽

Diamond Films ◽

Chemical Vapour ◽

Nanocrystalline Diamond ◽

Wear Rates ◽

Nanocrystalline Diamond Films ◽

Worn Surface

The nanocrystalline diamond films were deposited by microwave plasma enhanced chemical vapour deposition (PE-CVD) on Si (100) substrate. Reciprocating sliding tests were conducted using Si3N4 balls as a counter body. A method based on the construction of the Abbott curve representing the areas of pristine and worn surface in the wear scars was applied for estimation of the wear rate. The calculated wear rates were compared with the results obtained by profilometric measurements and direct measurement of the wear scars cross sections by scanning electron microscopy (SEM).

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Self-Supporting Nanocrystalline Diamond Foils – A New Concept for Crystalline Diamond on any Technical Surface

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.438.163 ◽

2010 ◽

Vol 438 ◽

pp. 163-169 ◽

Cited By ~ 10

Author(s):

Matthias A. Lodes ◽

Stefan M. Rosiwal ◽

Robert F. Singer

Keyword(s):

Thermal Conductivity ◽

Friction And Wear ◽

Vapour Deposition ◽

Chemical Vapour ◽

High Hardness ◽

Nanocrystalline Diamond ◽

Temperature Sensitive ◽

Light Metals ◽

Temperature Application ◽

Hot Filament

The manufacturing and application of self-supporting nanocrystalline diamond foils is introduced. The high temperature manufacturing of nanocrystalline diamond foils by hot-filament chemical vapour deposition (HFCVD) is separated from the low temperature application, allowing the coating of temperature sensitive materials, which cannot be coated by HFCVD conventionally. By coating appropriate template materials and stripping-off after the CVD-process, self-supporting, flexible nanocrystalline diamond foils with high hardness (> 70 GPa) and very low thermal conductivity (< 1 W/mK) with thicknesses of up to 100 µm can be produced. Lasercutting is an appropriate method for machining any desired geometry. Thus the possibility to use the extreme properties of diamond for protection against friction and wear on new substrate materials, e.g. steels, light metals and polymers, is generated.

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A Comparison of the Surface Properties of DLC and Nanocrystalline Diamond

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.336-338.1776 ◽

2007 ◽

Vol 336-338 ◽

pp. 1776-1779

Author(s):

Chong Mu Lee ◽

Kyung Ha Kim

Keyword(s):

Chemical Vapour Deposition ◽

Amorphous Carbon ◽

Photoelectron Spectroscopy ◽

Vapour Deposition ◽

Microwave Plasma ◽

Diamond Films ◽

Chemical Vapour ◽

Scanning Force Microscopy ◽

Nanocrystalline Diamond ◽

Hard Coatings

Diamond-like carbon (DLC) films have been deposited by radio frequency plasma enhanced chemical vapour deposition (rf-PECVD) with different Ar-CH4 mixtures. Nanocrystalline diamond films have been deposited by microwave plasma-enhanced chemical vapour deposition (MPCVD), using Ar-H2-CH4 mixtures. X-ray photoelectron spectroscopy (XPS) and nanotribological investigation (by scanning force microscopy) have been used to compare the mechanical properties and structures of these films. Highly orientated and non-orientated microcrystalline diamond films and MPCVD-produced amorphous carbon have also been studied by way of comparison. The diamond films exhibit a linear relationship between roughness and the coefficient of friction. The DLC and amorphous carbon have higher friction coefficients than the best performing diamond film, but may more easily be deposited as smooth coating. Possible applications for these various carbon-based films include microelectromechanical components, for which smooth, hard coatings are required.

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Effects of Surface Modification of Nanodiamond Particles for Nucleation Enhancement during Its Film Growth by Microwave Plasma Jet Chemical Vapour Deposition Technique

Advances in Materials Science and Engineering ◽

10.1155/2014/937159 ◽

2014 ◽

Vol 2014 ◽

pp. 1-5 ◽

Cited By ~ 3

Author(s):

Chii-Ruey Lin ◽

Da-Hua Wei ◽

Minh-Khoa BenDao ◽

Hong-Ming Chang ◽

Wei-En Chen ◽

...

Keyword(s):

Surface Modification ◽

Chemical Vapour Deposition ◽

Vapour Deposition ◽

Microwave Plasma ◽

Diamond Films ◽

Chemical Vapour ◽

Plasma Jet ◽

Nanocrystalline Diamond ◽

Initial Growth ◽

Nanocrystalline Diamond Films

The seedings of the substrate with a suspension of nanodiamond particles (NDPs) were widely used as nucleation seeds to enhance the growth of nanostructured diamond films. The formation of agglomerates in the suspension of NDPs, however, may have adverse impact on the initial growth period. Therefore, this paper was aimed at the surface modification of the NDPs to enhance the diamond nucleation for the growth of nanocrystalline diamond films which could be used in photovoltaic applications. Hydrogen plasma, thermal, and surfactant treatment techniques were employed to improve the dispersion characteristics of detonation nanodiamond particles in aqueous media. The seeding of silicon substrate was then carried out with an optimized spin-coating method. The results of both Fourier transform infrared spectroscopy and dynamic light scattering measurements demonstrated that plasma treated diamond nanoparticles possessed polar surface functional groups and attained high dispersion in methanol. The nanocrystalline diamond films deposited by microwave plasma jet chemical vapour deposition exhibited extremely fine grain and high smooth surfaces (~6.4 nm rms) on the whole film. These results indeed open up a prospect of nanocrystalline diamond films in solar cell applications.

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Nanocrystalline Diamond as a Dielectric for SOD Applications

MRS Proceedings ◽

10.1557/proc-1039-p13-02 ◽

2007 ◽

Vol 1039 ◽

Cited By ~ 1

Author(s):

Mose Bevilacqua ◽

Niall Tumilty ◽

Aysha Chaudhary ◽

Haitao Ye ◽

James E Butler ◽

...

Keyword(s):

Electrical Properties ◽

Grain Boundary ◽

Grain Boundaries ◽

Microwave Plasma ◽

Chemical Vapour ◽

Polycrystalline Diamond ◽

Growth Conditions ◽

Nanocrystalline Diamond ◽

Free Standing ◽

Single Crystal Diamond

AbstractNanocrystalline diamond (NCD) has been grown on oxide coated silicon wafers by microwave plasma assisted chemical vapour deposition using a novel seeding technique followed by optimised growth conditions, and leads to a highly-dense form of this material with grain sizes around 100nm for films approximately 1.5 microns thick. The electrical properties of these films have been investigated using Impedance Spectroscopy, which enables the contributions from sources characterised by differing capacitances, such as grain boundaries and grain interiors, to be isolated. After an initial acid clean the electrical properties of the film are not stable, and both grain boundaries and grains themselves contribute to the frequency dependant impedance values recorded. However, following mild oxidation grain boundary conduction is completely removed and the films become highly resistive (>1013 ohm/sq). This is most unusual, as conduction through NCD material is more normally dominated by grain boundary effects. Interestingly, the AC properties of these films are also excellent with a dielectric loss value (tan δ) as low as 0.002 for frequencies up to 10MHz. The dielectric properties of these NCD films are therefore as good as high quality free-standing (large grain) polycrystalline diamond films, and not too dissimilar to single crystal diamond, and are therefore ideally suited to future ‘silicon-on-diamond’ applications.

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Phase Transformation of Nanocrystalline Diamond Films: Effect of Methane Concentration

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.831.127 ◽

2020 ◽

Vol 831 ◽

pp. 127-131

Author(s):

S.Tipawan Khlayboonme ◽

Thowladda Warawoot

Keyword(s):

Phase Transformation ◽

Gas Phase ◽

Electron Density ◽

Microwave Plasma ◽

Diamond Films ◽

Chemical Vapor ◽

Nanocrystalline Diamond ◽

Graphite Phase ◽

Diamond Phase ◽

Nanocrystalline Diamond Films

Ultra-nanocrystalline diamond films were prepared by a microwave plasma-enhanced chemical vapor deposition reactor using CH4/H2 gas mixture with a power as low as 650 W. The effects of CH4 concentration on nanostructure of the films and gas-phase species in plasma were investigated. The CH4 concentrations of 1.5%, 3.0%, 3.5%, and 4.0% were used and balanced with H2 to a total flow rate of 200 sccm. Morphology and composition of the films were characterized by SEM, Raman spectroscopy and Auger spectroscopy. The gas-phase species and electron density in the plasma were explored by optical emission spectroscopy and plasma-impedance measurement. The increasing CH4 concentration from 1.5% to 4.0% increased C2Hx species and decreased electron density. Phase of the film transform from nano- into ultranano- diamond phase but the growth rate revealingly decreased from 300 to 210 nm/h. Raman spectra indicate the higher CH4 concentration promted phase of the film transiton from NCD to UNCD. While Auger spectra revealed that UNCD film deposited with 4.0%CH4 was composed of 90.52% diamond phase but only 9.48% of graphite phase. The relation between phase transformation of the films and growth mechnism controlled by gas-phase species in the plasma will be dissused.

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