Nanocrystalline Diamond as a Dielectric for SOD Applications

2007 ◽  
Vol 1039 ◽  
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.

scholarly journals Effects of Charge Compensation on Colossal Permittivity and Electrical Properties of Grain Boundary of CaCu3Ti4O12 Ceramics Substituted by Al3+ and Ta5+/Nb5+

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3294
Author(s):  
Jakkree Boonlakhorn ◽  
Jedsada Manyam ◽  
Pornjuk Srepusharawoot ◽  
Sriprajak Krongsuk ◽  
Prasit Thongbai
Keyword(s):  
Dielectric Properties ◽  
Electrical Properties ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Barrier Height ◽  
Potential Barrier ◽  
Charge Compensation ◽  
Solid State Reaction Method ◽  
Wide Frequency Range ◽  
Potential Barrier Height

The effects of charge compensation on dielectric and electrical properties of CaCu3Ti4-x(Al1/2Ta1/4Nb1/4)xO12 ceramics (x = 0−0.05) prepared by a solid-state reaction method were studied based on the configuration of defect dipoles. A single phase of CaCu3Ti4O12 was observed in all ceramics with a slight change in lattice parameters. The mean grain size of CaCu3Ti4-x(Al1/2Ta1/4Nb1/4)xO12 ceramics was slightly smaller than that of the undoped ceramic. The dielectric loss tangent can be reduced by a factor of 13 (tanδ ~0.017), while the dielectric permittivity was higher than 104 over a wide frequency range. Impedance spectroscopy showed that the significant decrease in tanδ was attributed to the highly increased resistance of the grain boundary by two orders of magnitude. The DFT calculation showed that the preferential sites of Al and Nb/Ta were closed together in the Ti sites, forming self-charge compensation, and resulting in the enhanced potential barrier height at the grain boundary. Therefore, the improved dielectric properties of CaCu3Ti4-x(Al1/2Ta1/4Nb1/4)xO12 ceramics associated with the enhanced electrical properties of grain boundaries. In addition, the non-Ohmic properties were also improved. Characterization of the grain boundaries under a DC bias showed the reduction of potential barrier height at the grain boundary. The overall results indicated that the origin of the colossal dielectric properties was caused by the internal barrier layer capacitor structure, in which the Schottky barriers at the grain boundaries were formed.

Crystalline perfection of chemical vapor deposited diamond films

1990 ◽  
Vol 5 (8) ◽  
pp. 1591-1594 ◽  
Author(s):  
A. V. Hetherington ◽  
C. J. H. Wort ◽  
P. Southworth
Keyword(s):  
Grain Boundaries ◽  
Microwave Plasma ◽  
Diamond Films ◽  
Stacking Faults ◽  
Chemical Vapor ◽  
Cvd Diamond ◽  
Growth Conditions ◽  
Crystalline Perfection ◽  
Planar Defects ◽  
Chemical Vapor Deposited

The crystalline perfection of microwave plasma assisted chemical vapor deposited (MPACVD) diamond films grown under various conditions has been examined by TEM. Most CVD diamond films thus far reported contain a high density of defects, predominantly twins and stacking faults on {111} planes. We show that under appropriate growth conditions, these planar defects are eliminated from the center of the crystallites, and occur only at grain boundaries where the growing crystallites meet.

Evaluation of Wear Rate of Nanocrystalline Diamond Films Using Abbott Curve

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).

scholarly journals Phosphorous Doping of Microcrystalline CVD Diamond Using Modified Conditions

2007 ◽  
Vol 1039 ◽  
Author(s):  
Ken Haenen ◽  
Andrada Lazea ◽  
Vincent Mortet ◽  
Jan D'Haen ◽  
Peter Geithner ◽  
...  
Keyword(s):  
Microwave Plasma ◽  
Growth Parameters ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Cvd Diamond ◽  
Growth Conditions ◽  
Diamond Surfaces ◽  
Cvd Growth ◽  
Oriented Polycrystalline ◽  
Electron Back Scattered Diffraction

AbstractPhosphorous-doping of predominantly (110) oriented polycrystalline CVD diamond films is presented. Incorporation of phosphorous into the diamond grains was accomplished by using novel microwave plasma enhanced chemical vapor deposition (MW PE CVD) growth conditions. The substitutional nature of the phosphorous atom was confirmed by applying the quasi-steady-state photocurrent technique (PC) and cathodoluminescence (CL) measurements at low temperature. Topographical information and the relation between substrate and P-doped film grain orientation was obtained with scanning electron microscopy (SEM) and electron back-scattered diffraction (EBSD). The optimized growth parameters for P-doped layers on (110) oriented polycrystalline diamond differ substantially from the standard conditions reported in literature for P-doping of single crystalline (111) and (100) oriented diamond surfaces.

A Comparison of the Surface Properties of DLC and Nanocrystalline Diamond

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.

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

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
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.

Bonding Regeneration: The Driving Force of Hetero-Epitaxial Diamond Grain Coalescence on (001) Silicon

1998 ◽  
Vol 529 ◽  
Author(s):  
R.Q. Zhang ◽  
X. Jiang ◽  
C.L. Jia ◽  
S.-T. Lee
Keyword(s):  
Grain Boundary ◽  
Silicon Substrate ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
High Resolution Electron Microscopy ◽  
Diamond Growth ◽  
Plasma Chemical Vapor Deposition ◽  
Single Crystal Diamond ◽  
Diamond Grain ◽  
Grain Coalescence

AbstractThe grain coalescence phenomenon in the growth of heteroepitaxial diamond film on (001) silicon substrate by microwave plasma chemical vapor deposition was examined by using high-resolution electron microscopy. It was shown that this phenomenon evidently occurs between two diamond grains with a small-angle tilt. The coalescence was completed after some more growth steps following the meeting of such two grains, indicating the difficulty for the lattice matching in grain boundary. By performing simulation of a step-by-step growth of two diamond grains on a (001) silicon substrate with molecular orbital PM3 method, it was shown that the bonding regeneration between the two grains is essential for the coalescence and the coalescence is only possible when the orientation difference between the grains is sufficiently small so as to allow efficient overlap of electron cloud in the grain boundary. This study indicates that single crystal diamond growth may be possible by the current CVD growth techniques via further reduction of the surface roughness to gain a heteroepitaxy with very small grain tilting.

Progress on Preferential Etching and Phosphorus Doping of Single Crystal Diamond

2014 ◽  
Vol 1634 ◽  
Author(s):  
Timothy A. Grotjohn ◽  
Dzung T. Tran ◽  
M. Kagan Yaran ◽  
Thomas Schuelke
Keyword(s):  
Substrate Temperature ◽  
Single Crystal ◽  
Epitaxial Growth ◽  
Microwave Plasma ◽  
Hydrogen Plasma ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Growth Conditions ◽  
Room Temperature Resistivity ◽  
Single Crystal Diamond

ABSTRACTPhosphorus is incorporated into single crystal diamond during epitaxial growth at higher concentrations on the (111) crystallographic surface than on the (001) crystallographic surface. To form n+-type regions in diamond for semiconductor devices it is beneficial to deposit on the (111) surface. However, diamond deposition is faster and of higher quality on the (001) surface. A preferential etch method is described that forms inverted pyramids on the (001) surface of a substrate diamond crystal, which opens (111) faces for improved phosphorus incorporation. The preferential etching occurs on the surface in regions where a nickel film is deposited. The etching is performed in a microwave generated hydrogen plasma operating at 160 Torr with the substrate temperature in the range of 800-950 °C. The epitaxial growth of diamond with high phosphorus concentrations exceeding 1020 cm-3 is performed using a microwave plasma-assisted chemical vapor deposition process. Successful growth conditions were achieved with a feedgas mixture of 0.25% methane, 500 ppm phosphine and hydrogen at a pressure of 160 Torr and a substrate temperature of 950-1000°C. The room temperature resistivity of the phosphorus-doped diamond is 120-150 Ω-cm and the activation energy is 0.027 eV.

scholarly journals Nanocrystalline diamond (NCD): an insight into structure-property relationships

2014 ◽  
Vol 70 (a1) ◽  
pp. C1334-C1334
Author(s):  
Natalia Dubrovinskaia ◽  
Leonid Dubrovinsky ◽  
Natalia Solopova ◽  
Artem Abakumov ◽  
Anatoly Snigirev ◽  
...  
Keyword(s):  
Glassy Carbon ◽  
Polycrystalline Diamond ◽  
High Energy ◽  
Nanocrystalline Diamond ◽  
High Yield ◽  
Structure Property ◽  
X Ray ◽  
Structure Property Relationships ◽  
Single Crystal Diamond ◽  
Insight Into

Nanocrystalline diamond (NCD) is a unique material we produce by direct conversion of glassy carbon into diamond at ca. 20 GPa and 2200 K in a multi anvil press. One of precursor materials we use is commercially available in the form of glassy carbon balls with a diameter of 20 to 50 microns. NCD demonstrates superior mechanical properties (e.g. extremely high yield strength under confining pressure) and has been successfully used for ultra-high static pressure generation (above 600 GPa) in a double-stage diamond anvil cell (DAC) (Ref. 1). To elucidate structure-property relationships in this extremely strong and seemingly inscrutable material we have investigated its microstructure using HRTEM and HAADF-STEM, measured its compressibility by means of synchrotron X-ray diffraction in a DAC, and evaluated its hardness in comparison to that of the hardest known materials - single-crystal diamond and nano-polycrystalline diamond (NPD) (Ref. 2). An additional insight into the volume compressibility was obtained due to X-ray phase contrast micro-imaging using a coherent high-energy synchrotron radiation. The established structure-property relationships will be presented and analyzed.

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