DIAMOND DEPOSITION ON WC/Co ALLOY WITH A MOLYBDENUM INTERMEDIATE LAYER

2005 ◽  
Vol 12 (04) ◽  
pp. 499-504
Author(s):  
SHA LIU ◽  
ZHI-MING YU ◽  
DAN-QING YI
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Intermediate Layer ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Cvd Diamond ◽  
Diamond Growth ◽  
Diamond Coatings ◽  
Sputter Deposited ◽  
Diamond Grain

It is known that in the condition of chemical vapor deposition (CVD) diamond process, molybdenum is capable of forming carbide known as the "glue" which promotes growth of the CVD diamond, and aids its adhesion by (partial) relief of stresses at the interface. Furthermore, the WC grains are reaction bonded to the Mo 2 C phase. Therefore, molybdenum is a good candidate material for the intermediate layer between WC–Co substrates and diamond coatings. A molybdenum intermediate layer of 1–3 μm thickness was magnetron sputter-deposited on WC/Co alloy prior to the deposition of diamond coatings. Diamond films were deposited by hot filament chemical vapor deposition (HFCVD). The chemical quality, morphology, and crystal structure of the molybdenum intermediate layer and the diamond coatings were characterized by means of SEM, EDX, XRD and Raman spectroscopy. It was found that the continuous Mo intermediate layer emerged in spherical shapes and had grain sizes of 0.5–1.5 μm after 30 min sputter deposition. The diamond grain growth rate was slightly slower as compared with that of uncoated Mo layer on the WC–Co substrate. The morphologies of the diamond films on the WC–Co substrate varied with the amount of Mo and Co on the substrate. The Mo intermediate layer was effective to act as a buffer layer for both Co diffusion and diamond growth.

Effects of CH4 Concentration on CVD Diamond Coatings Deposited on Cemented Carbide Cutting Cools

2006 ◽  
Vol 532-533 ◽  
pp. 480-483 ◽  
Author(s):  
Wen Zhuang Lu ◽  
Dun Wen Zuo ◽  
Min Wang ◽  
Feng Xu
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Great Influence ◽  
Chemical Vapor ◽  
Cvd Diamond ◽  
Cemented Carbide ◽  
Diamond Coatings ◽  
Ch4 Concentration

Chemical vapor deposition (CVD) diamond coatings were deposited on cemented carbide cutting cools by an electron-assisted hot filament chemical vapor deposition (EACVD) equipment developed by the authors. The CVD diamond coatings were studied by Scanning Electron Microscope (SEM) and Raman Scattering Spectroscopy (Raman). The experimental results show that CH4 concentration in the source gas performs great influence on the micro-structure, surface roughness, composition, residual stress and adhesion of the CVD diamond coatings. The increase of CH4 concentration results the change of diamond crystal from {111} orientation to {100} orientation, the decrease of the surface roughness and the increase of sp2 carbon in the CVD diamond coatings. A residual compressive stress exists in the CVD diamond coatings. The residual stress decreases with increasing CH4 concentration. A higher or lower CH4 concentration tends to reduce adhesion stress of the continuous CVD diamond coatings.

A sequential Raman analysis of the growth of diamond films on silicon substrates in a microwave plasma assisted chemical vapor deposition reactor

1997 ◽  
Vol 12 (10) ◽  
pp. 2686-2698 ◽  
Author(s):  
L. Fayette ◽  
B. Marcus ◽  
M. Mermoux ◽  
N. Rosman ◽  
L. Abello ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Sequential Analysis ◽  
Microwave Plasma ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Diamond Growth ◽  
Internal Stresses ◽  
Nucleation Density ◽  
Silicon Substrates

A sequential analysis of the growth of diamond films on silicon substrates in a microwave plasma assisted chemical vapor deposition (CVD) reactor has been performed by Raman spectroscopy. The plasma was switched off during measurements, but the substrate heating was maintained to minimize thermoelastic stresses. The detectivity of the present experimental setup has been estimated to be about a few tens of μmg/cm2. From such a technique, one expects to analyze different aspects of diamond growth on a non-diamond substrate. The evolution of the signals arising from the substrate shows that the scratching treatment used to increase the nucleation density induces an amorphization of the silicon surface. This surface is annealed during the first step of deposition. The evolution of the line shape of the spectra indicates that the non-diamond phases are mainly located in the grain boundaries. The variation of the integrated intensity of the Raman signals has been interpreted using a simple absorption model. A special emphasis was given to the evolution of internal stresses during deposition. It was verified that compressive stresses were generated when coalescence of crystals took place.

Effect of Carbon Concentration on the Optical Properties of Nanocrystalline Diamond Films Deposited by Hot-Filament Chemical Vapor Deposition Method

2008 ◽  
Vol 8 (5) ◽  
pp. 2534-2539
Author(s):  
Linjun Wang ◽  
Jianmin Liu ◽  
Ling Ren ◽  
Qingfeng Su ◽  
Weimin Shi ◽  
...  
Keyword(s):  
Grain Size ◽  
Optical Properties ◽  
Chemical Vapor Deposition ◽  
Carbon Concentration ◽  
Diamond Film ◽  
Vapor Deposition ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Diamond Grain ◽  
Hot Filament

With reducing diamond grain size to nano-grade, the increase of grain boundaries and non-diamond phase will result in the change of the optical properties of chemical vapor deposition (CVD) diamond films. In this paper, the structure, morphology and optical properties of nanocrystalline diamond (NCD) films, deposited by hot-filament chemical vapor deposition (HFCVD) method under different carbon concentration, are investigated by SEM, Raman scattering spectroscopy, as well as optical transmission spectra and spectroscopic ellipsometry. With increasing the carbon concentration during the film deposition, the diamond grain size is reduced and thus a smooth diamond film can be obtained. According to the data on the absorption coefficient in the wavelength range from 200 to 1100 nm, the optical gap of the NCD films decreases from 4.3 eV to 3.2 eV with increasing the carbon concentration from 2.0% to 3.0%. From the fitting results on the spectroscopic ellipsometric data with a four-layer model in the photon energy range of 0.75–1.5 eV, we can find the diamond film has a lower refractive index (n) and a higher extinction coefficient (k) when the carbon concentration increases.

Epitaxial Growth of Diamond on an Iridium (100) Substrate by Microwave Plasma-Assisted Chemical Vapor Deposition

1998 ◽  
Vol 555 ◽  
Author(s):  
Toshiki Tsubota ◽  
Shigenori Tsuruga ◽  
Takeyasu Saito ◽  
Katsuki Kusakabe ◽  
Shigeharu Morooka ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Substrate Temperature ◽  
Vapor Deposition ◽  
Methane Concentration ◽  
Microwave Plasma ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Diamond Growth ◽  
Negative Bias ◽  
Diamond Particles

AbstractDiamond films were grown heteroepitaxially on iridium (100) substrates by microwave plasma-assisted chemical vapor deposition (MPCVD) using methane gas as the carbon source. The iridium substrate, which was formed on a MgO (100) substrate by means of sputtering at 850 °C, was treated by imposing a negative bias between -150 and -200 V for 15 min. Methane concentration and substrate temperature were maintained at 3° and 650–740 °c, respectively. At a substrate temperature of 740 °C, diamond particles were formed at a population density of (0.15- 1.5)x108 cm-2, and most of them were oriented to MgO (100). After a further reaction for 1 h under conditions which were optimized for diamond growth, the oriented diamond particles were coalesced, and islands of (100) diamond were formed.

Chemical Vapor Deposition of Diamond Films Using Water:Alcohol:Organic-Acid Solutions

1992 ◽  
Vol 242 ◽  
Author(s):  
R. A. Rudder ◽  
J. B. Posthill ◽  
G. C. Hudson ◽  
D. P. Malta ◽  
R. E. Thomas ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Water Vapor ◽  
Vapor Deposition ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Power Input ◽  
Low Pressure ◽  
Diamond Growth ◽  
Vapor Deposition Technique

ABSTRACTA low pressure chemical vapor deposition technique using water-alcohol vapors has been developed for the deposition of polycrystalline diamond films and homoepitaxial diamond films. The technique uses a low pressure (0.50 – 1.00 Torr) rf-induction plasma to effectively dissociate the water vapor into atomic hydrogen and OH. Alcohol vapors admitted into the chamber with the water vapor provide the carbon balance to produce diamond growth. At 1.00 Torr, high quality diamond growth occurs with a gas phase concentration of water approximately equal to 47% for methanol, 66% for ethanol, and 83% for isopropanol. A reduction in the critical power necessary to magnetically couple to the plasma gas is achieved through the addition of acetic acid to the water.alcohol solution. The lower input power allows lower temperature diamond growth. Currently, diamond depositions using water:methanol:acetic-acid are occurring as low as 300 ° C with only about 500 W power input to the 50 mm diameter plasma tube.

TEM cathodoluminescence of chemical vapor deposited diamond

1990 ◽  
Vol 48 (4) ◽  
pp. 620-621
Author(s):  
R.J. Graham ◽  
Mark M. Disko ◽  
T.D. Moustakas
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Cvd Diamond ◽  
Tungsten Filament ◽  
Electronic Information ◽  
Wear Resistant Coatings ◽  
Chemical Vapor Deposited ◽  
Potential Applications

Diamond films grown by chemical vapor deposition (CVD) are curently of great interest with potential applications in semiconductors and as wear resistant coatings. In order to understand and optimize the growth and properties of these films, it is necessary to characterize their microstructure. While such techniques as TEM and cathodoluminescence (CL) (in a SEM) can be used independently to provide microstructural and optical/electronic information respectively, the direct correlation of these two pieces of information is highly desirable. This is possible using the TEM CL technique (CL in a TEM) because the electron transparent specimen allows a direct comparison of CL with microstructure. The preliminary results obtained for CVD diamond films by this technique are presented here.The films examined were grown on a silicon (100) substrate by filament assisted CVD from a mixture of methane (2% vol.) and hydrogen at a pressure of 30 torr, using a tungsten filament operated at 1800°C.

scholarly journals Low Temperature Growth of Ultra-Nanocrystalline Diamond on Glass Substrates for Field Emission Applications

1999 ◽  
Vol 593 ◽  
Author(s):  
T. D. Corrigan ◽  
A. R. Krauss ◽  
D. M. Gruen ◽  
O. Auciello ◽  
R. P. H. Chang
Keyword(s):  
Chemical Vapor Deposition ◽  
Field Emission ◽  
Vapor Deposition ◽  
Microwave Plasma ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Cost Effective ◽  
Cvd Diamond ◽  
Glass Substrates ◽  
Cvd Method

ABSTRACTRecent studies of field emission from diamond have focused on the feasibility of growing diamond films on glass substrates, which are the preferred choice for cost-effective, large area flat panel displays. However, diamond growth on glass requires temperatures < 500 °C, which is much lower than the temperature needed for growing conventional microwave plasma chemical vapor deposition (CVD) diamond films. In addition, it is desirable to minimize the deposition time for cost-effective processing. We have grown ultrananocrystalline diamond (UNCD) films using a unique microwave plasma technique that involves CH4-Ar gas mixtures, as opposed to the conventional CH4-H2 plasma CVD method. The growth species in the CH4-Ar CVD method are C2 dimers, resulting in lower activation energies and consequently the ability to grow diamond at lower temperatures than conventional CVD diamond processes. For the work discussed here, the UNCD films were grown with plasma-enhanced chemical vapor deposition (PECVD) at low temperatures on glass substrates coated with Ti thin films. The turn-on field was as low as 3 V/μm for a film grown at 500 °C with a gas chemistry of l%CH4/99%Ar at 100 Torr, and 7 V/μm for a film grown at 350 °C. UV Raman spectroscopy revealed the presence of high quality diamond in the films.

Identification of hydrocarbon precursors to diamond in chemical vapor deposition using carbon monoxide reagent

1993 ◽  
Vol 8 (9) ◽  
pp. 2245-2249 ◽  
Author(s):  
Curtis E. Johnson ◽  
Wayne A. Weimer
Keyword(s):  
Carbon Monoxide ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Microwave Plasma ◽  
Diamond Films ◽  
Chemical Vapor ◽  
High Energy ◽  
Diamond Growth ◽  
Methyl Radical ◽  
Gaseous Products

Diamond films were grown by microwave plasma-assisted chemical vapor deposition using mixtures of 13CH4 and CO. Mass spectrometry was used to identify CO, CH4, and C2H2 as the stable gaseous products in the reactor exhaust gas. By comparing gaseous 13C compositions with that of the diamond films, the efficiency of diamond growth from methane (possibly via the methyl radical) is found to be about two orders of magnitude higher than that for carbon monoxide. Most of the diamond that is formed from the CO reagent results from the conversion of CO to hydrocarbons. The conversion of CO to hydrocarbons is attributed to activation of CO by high-energy electrons in the plasma.

Sign in / Sign up

Export Citation Format

Share Document