EFFECT OF DEPOSITING TEMPERATURE ON THE INTERFACIAL ADHESION OF NANOCRYSTALLINE DIAMOND FILMS GROWN ON TITANIUM BY MICROWAVE PLASMA ASSISTED CVD PROCESS

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1725-1732
Author(s):  
SYED JAWID ASKARI ◽  
ALI IMRAN MERCHANT
Keyword(s):  
Microwave Plasma ◽  
Chemical Vapor ◽  
Nanocrystalline Diamond ◽  
Complex Nature ◽  
Nucleation Density ◽  
Plasma Chemical Vapor Deposition ◽  
Force Microscopy ◽  
Thermal Expansion Coefficients ◽  
Atomic Force ◽  
Indentation Tests

In contrast to their exceptional mechanical properties, titanium and its alloys possess poor friction and wear characteristics. Nanocrystalline diamond (NCD) films appear to be a promising solution for their tribological problem due to their smooth surfaces and small grain size. However, the synthesis of a well adherent NCD film on titanium and its alloys is always complicated due to the different thermal expansion coefficients of the two materials, the complex nature of the interlayer formed during diamond deposition, and the difficulty in achieving very high nucleation density. In this work NCD thin films have been deposited on pure Ti substrates in a microwave plasma chemical vapor deposition (MWPCVD) reactor under fixed pressure and methane concentration in hydrogen but over a wide temperature range. The effects of depositing temperatures on the adhesion of films are evaluated using Rockwell indentation tests. It is found that by increasing the deposition temperature the films bonding deteriorates. The films synthesized are characterized by field emission scanning electron microscopy, atomic force microscopy, Raman spectroscopy, and X-ray diffraction.

Development of CVD Diamond Thin Films on Titanium Substrate and Study their Tribological Behavior

2011 ◽  
Vol 399-401 ◽  
pp. 1994-1997 ◽  
Author(s):  
Syed Jawid Askari
Keyword(s):  
Thin Films ◽  
Microwave Plasma ◽  
Titanium Substrate ◽  
Chemical Vapor ◽  
Complex Nature ◽  
Nucleation Density ◽  
Plasma Chemical Vapor Deposition ◽  
Force Microscopy ◽  
Thermal Expansion Coefficients ◽  
Indentation Tests

Abstract: In contrast to their exceptional mechanical properties, titanium and its alloys possess poor friction and wear characteristics. Nanocrystalline diamond (NCD) films appear to be a promising solution for their tribological problem due to their smooth surfaces and small grain size. However, the synthesis of a well adherent NCD film on titanium and its alloys is always complicated due to the different thermal expansion coefficients of the two materials, the complex nature of the interlayer formed during diamond deposition, and the difficulty in achieving very high nucleation density. In this work NCD thin films have been deposited on pure Ti substrates in a microwave plasma chemical vapor deposition (MWPCVD) reactor under fixed pressure and methane concentration in hydrogen but over a wide temperature range. The effects of depositing temperatures on the adhesion of films are evaluated using Rockwell indentation tests. It is found that by increasing the deposition temperature the films bonding deteriorates. The films synthesized are characterized by field emission scanning electron microscopy, atomic force microscopy, Raman spectroscopy, and X-ray diffraction.

Nanocrystalline Diamond Film Produced by Argon Addition in the CH4-H2 Microwave CVD Plasmas

2007 ◽  
Vol 26-28 ◽  
pp. 615-618
Author(s):  
Syed Jawid Askari ◽  
Fan Xiu Lu
Keyword(s):  
Diamond Film ◽  
Microwave Plasma ◽  
Pure Titanium ◽  
Chemical Vapor ◽  
Nanocrystalline Diamond ◽  
Complex Nature ◽  
Nucleation Density ◽  
Diamond Coatings ◽  
Plasma Chemical Vapor Deposition ◽  
Thermal Expansion Coefficients

Diamond coatings on pure titanium substrates are of interest for tribological and biomedical implants. However, due to the different thermal expansion coefficients of the two materials, the complex nature of the interlayer formed during diamond deposition, and the difficulty in achieving very high nucleation density, it is hard to deposit adherent thin diamond layers on titanium. The aim of the present research was to successfully produce smooth and well adherent nanocrystalline diamond (NCD) film on a pure Ti substrate using the microwave plasma chemical vapor deposition (MWPCVD) method. The influence of Argon addition to CH4/H2 plasma on the crystallinity, morphology and growth of the diamond film deposited by MWPCVD was investigated using field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), Xray diffraction (XRD) and Raman spectroscopy.

Tribological Characteristics of CVD Nanocrystalline Diamond Film Grown by Bias Enhanced Nucleation Process

2011 ◽  
Vol 264-265 ◽  
pp. 1439-1443
Author(s):  
Syed Jawid Askari
Keyword(s):  
Friction Coefficient ◽  
Microwave Plasma ◽  
Research Work ◽  
Chemical Vapor ◽  
Nanocrystalline Diamond ◽  
Complex Nature ◽  
Nucleation Density ◽  
Plasma Chemical Vapor Deposition ◽  
Dry Air ◽  
Thermal Expansion Coefficients

Nanocrystalline diamond (NCD) films on titanium alloys are of importance for tribology and biomedical implants. However, due to the different thermal expansion coefficients of the two materials, the complex nature of the interlayer formed during diamond deposition, and the difficulty in achieving high nucleation density, it is difficult to deposit adherent NCD films on titanium and its alloys. The aim of this research work is to successfully produce smooth, low roughness and well adherent NCD film on a pure Ti substrate by bias enhanced nucleation (BEN) process using microwave plasma chemical vapor deposition (MWPCVD) method. The friction coefficient was estimated to be around 0.06 in dry air using ball on disk tribometer with reciprocating sliding against a cemented carbide ball of 10 mm diameter at a high contact load of 20 N in dry air. The friction coefficient of bare Ti was between 0.55-06.

Study of the Adhesion and Biocompatibility of Nanocrystalline Diamond (NCD) Films on 3C-SiC Substrates

2009 ◽  
Vol 1203 ◽  
Author(s):  
Humberto Gomez ◽  
Christopher L. Frewin ◽  
Ashok Kumar ◽  
Stephen Saddow ◽  
Christopher Locke
Keyword(s):  
Microwave Plasma ◽  
Chemical Vapor ◽  
Nanocrystalline Diamond ◽  
Grain Structure ◽  
Plasma Chemical Vapor Deposition ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Analysis ◽  
Fixed Cell

AbstractThe unique material characteristics of silicon carbide (SiC) and nanocrystalline diamond (NCD) present solutions to many problems in conventional MEMS applications and especially for biologically compatible devices. Both materials have a wide bandgap along with excellent optical, thermal and mechanical properties. Initial experiments were performed for NCD films grown on 3C-SiC using a microwave plasma chemical vapor deposition (MPCVD) reactor. It was observed from the atomic force microscopy (AFM) analysis that the NCD films on 3C-SiC possess a more uniform grain structure, with sizes ranging from approximately 5 – 10 nm, whereas on the Si surface, the NCD has large, non-unioform inclusions of grains ≈1 μm in size. The in vitro biocompatibility performance of NCD/3C-SiC was measured utilizing 2 immortalized neural cell lines: H4 human neuroglioma (ATCC #HTB-148) and PC12 rat pheochromocytoma (ATCC #CRL-1721). MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was used to measure viability of the cells for 96 hours and live/ fixed cell. AFM was performed to determine the general cell morphology. The H4 cell line shows a good biocompatibility level with hydrogen treated NCD as compared with the cell treated polystyrene control well, while the PC12 cells show decreased viability on the NCD surfaces.

Low Temperature Growth of CVD Nanocrystalline Diamond Thin Film by Designed SWP-CVD with Various Working Pressures

2019 ◽  
Vol 11 (9) ◽  
pp. 1292-1297
Author(s):  
Yeong Min Park ◽  
Moon Ki Han ◽  
Mun Ki Bae ◽  
Tae Gyu Kim
Keyword(s):  
Microwave Plasma ◽  
Chemical Properties ◽  
Chemical Vapor ◽  
Nanocrystalline Diamond ◽  
Slot Antenna ◽  
High Quality ◽  
Plasma Chemical Vapor Deposition ◽  
Force Microscopy ◽  
Diamond Thin Film ◽  
Atomic Force

Nanocrystalline diamond (NCD) is exceptionally useful for a variety of applications and is of significant interest to researchers in technological and scientific fields due to its excellent mechanical and chemical properties, such as its hardness and high thermal conductivity. We have modified a microwave plasma chemical vapor deposition (MPCVD; Astex Inc.) system with a slot antenna designed for surface wave plasma (SWP) and successfully fabricated high quality thin NCD film. This SWP-CVD process fabricates high quality diamond film at 300 °C, while a normal MPCVD process requires the temperature of the substrate to be above 800 °C. We studied the fabricated NCD samples in detail, measuring their surface morphology by field emission scanning electron microscopy (FESEM); their structural-chemical properties by Raman spectroscopy; and their surface roughness by atomic force microscopy (AFM).

Multivariable study on homoepitaxial diamond growth using isotopically enriched carbon-13 gas mixtures

2009 ◽  
Vol 24 (2) ◽  
pp. 493-498 ◽  
Author(s):  
Gopi K. Samudrala ◽  
Yogesh K. Vohra
Keyword(s):  
Microwave Plasma ◽  
Chemical Vapor ◽  
Nitrogen Vacancy ◽  
Diamond Growth ◽  
Plasma Chemical ◽  
Rocking Curve ◽  
X Ray ◽  
Plasma Chemical Vapor Deposition ◽  
Force Microscopy ◽  
Atomic Force

We report our observations on the homoepitaxial diamond growth by microwave plasma chemical vapor deposition (MPCVD) experiments on Type Ib diamond substrates conducted by varying three independent variables. In a feed gas mixture of H2, N2, O2, and 13CH4, the amount of nitrogen was varied in the range of 0 to 4000 ppm, the amount of methane was varied from 2% CH4/H2 to 6% CH4/H2, and the substrate temperature was varied in the range of 850 to 1200 °C. We used isotopically enriched carbon-13 methane gas as the source of carbon in the plasma to clearly distinguish the grown diamond layer from the underlying substrate using Raman spectroscopy. The x-ray rocking curve measurements confirmed the homoepitaxial nature of the deposited layers with a slight increase in the full width at half-maximum for sample grown with the highest nitrogen content in the plasma. Optical and atomic force microscopy revealed dramatic changes in surface morphology with variation in each parameter. The nitrogen incorporation in carbon-13 diamond layers was monitored through photoluminescence spectroscopy of nitrogen–vacancy complexes. A twentyfold increase in diamond growth rate was clearly achieved in this multivariable study.

scholarly journals Synthesis of ultrasmooth nanostructured diamond films by microwave plasma chemical vapor deposition using a He/H2/CH4/N2gas mixture

2006 ◽  
Vol 21 (10) ◽  
pp. 2675-2682 ◽  
Author(s):  
S. Chowdhury ◽  
Damon A. Hillman ◽  
Shane A. Catledge ◽  
Valery V. Konovalov ◽  
Yogesh K. Vohra
Keyword(s):  
Gas Flow ◽  
Microwave Plasma ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Optical Emission ◽  
X Ray Diffraction ◽  
Plasma Chemical Vapor Deposition ◽  
Force Microscopy ◽  
Atomic Force ◽  
Gas Flow Ratio

Ultrasmooth nanostructured diamond (USND) films were synthesized on Ti–6Al–4V medical grade substrates by adding helium in H2/CH4/N2plasma and changing the N2/CH4gas flow from 0 to 0.6. We were able to deposit diamond films as smooth as 6 nm (root-mean-square), as measured by an atomic force microscopy (AFM) scan area of 2 μm2. Grain size was 4–5 nm at 71% He in (H2+ He) and N2/CH4gas flow ratio of 0.4 without deteriorating the hardness (∼50–60 GPa). The characterization of the films was performed with AFM, scanning electron microscopy, x-ray diffraction (XRD), Raman spectroscopy, and nanoindentation techniques. XRD and Raman results showed the nanocrystalline nature of the diamond films. The plasma species during deposition were monitored by optical emission spectroscopy. With increasing N2/CH4feedgas ratio (CH4was fixed) in He/H2/CH4/N2plasma, a substantial increase of CN radical (normalized by Balmer Hαline) was observed along with a drop in surface roughness up to a critical N2/CH4ratio of 0.4. The CN radical concentration in the plasma was thus correlated to the formation of ultrasmooth nanostructured diamond films.

Deposition of a Well-Adherent Nano-Crystalline Diamond Coating on Titanium Using CH4-H2 Gas Mixture

2007 ◽  
Vol 561-565 ◽  
pp. 1145-1148
Author(s):  
Syed Jawid Askari ◽  
Fan Xiu Lu
Keyword(s):  
Diamond Film ◽  
Microwave Plasma ◽  
Pure Titanium ◽  
Titanium Substrate ◽  
Chemical Vapor ◽  
Complex Nature ◽  
Nucleation Density ◽  
Thermal Expansion Coefficients ◽  
Nano Crystalline ◽  
Average Grain Size

The deposition of a well adherent diamond film on titanium and its alloys is always complicated due to the different thermal expansion coefficients of the two materials, the complex nature of the interlayer formed during diamond deposition, and the difficulty in achieving very high nucleation density. In this work well-adherent and smooth nano-crystalline diamond film was successfully deposited on pure titanium substrate by microwave plasma assisted chemical vapor deposition (MWPCVD) method in CH4/H2 environment. It is found that the average grain size was less than 20 nm with a surface roughness value as low as 28nm. Of particular interest in this study was the exceptional adhesion of approximately 2μm-thick diamond film to the metal substrate as observed by indentation testing up to 150 kg load. Experimental results on growth mechanism and obtaining good adhesion are discussed.

Growth of Highly (110) Oriented Diamond Film by Microwave Plasma Chemical Vapor Deposition

2018 ◽  
Vol 281 ◽  
pp. 893-899 ◽  
Author(s):  
Yi Fan Xi ◽  
Jian Huang ◽  
Ke Tang ◽  
Xin Yu Zhou ◽  
Bing Ren ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Microwave Plasma ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Nucleation Density ◽  
Plasma Chemical ◽  
Plasma Chemical Vapor Deposition ◽  
Si Substrates ◽  
Nucleation Stage

In this study, we propose a simple and effective approach to enhance (110) orientation in diamond films grown on (100) Si substrates by microwave plasma chemical vapor deposition. It is found that the crystalline structure of diamond films strongly rely on the CH4 concentration in the nucleation stage. Under the same growth condition, when the CH4 concentration is less than 7% (7%) in the nucleation stage, the diamond films exhibit randomly oriented structure; once the value exceeds 7%, the deposited films are strongly (110) oriented. It could be verified by experiments that the formation of (110) orientation in diamond films are related to the high nucleation density and high fraction of diamond-like carbon existing in nucleation samples.

Insights into the ion-assisted nucleation of diamond on silicon

1997 ◽  
Vol 12 (12) ◽  
pp. 3354-3366 ◽  
Author(s):  
Sean P. McGinnis ◽  
Michael A. Kelly ◽  
Stig B. Hagström
Keyword(s):  
Microwave Plasma ◽  
Chemical Vapor ◽  
Nucleation Density ◽  
Thermal Spike ◽  
Plasma Chemical ◽  
Ion Energy ◽  
Ion Energy Distribution ◽  
Plasma Chemical Vapor Deposition ◽  
Preferential Sputtering ◽  
Nucleation Mechanisms

The ion-assisted nucleation of diamond was studied in a microwave plasma chemical vapor deposition system to gain insights into the processes controlling this phenomenon. The dependence of the nucleation density on bias voltage and temperature, as well as experiments with an electrically isolated substrate, are consistent with an ion bombardment mechanism for diamond nucleation. However, the growth of these nuclei is dominated by neutral species rather than ions. Measurements of the bias current under various conditions also provide details on the roles of the incident ion flux and substrate electron emission during this process. Furthermore, Monte Carlo simulations of the ion energy distribution at the substrate are compared to experimental measurements. Preferential sputtering, thermal spike, and carbon subplantation nucleation mechanisms are assessed based on the experimental and modeling results.

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