Coalesced oriented diamond films on nickel

1998 ◽  
Vol 13 (5) ◽  
pp. 1120-1123 ◽  
Author(s):  
P. C. Yang ◽  
C. A. Wolden ◽  
W. Liu ◽  
R. Schlesser ◽  
R. F. Davis ◽  
...  
Keyword(s):  
Gas Phase ◽  
Profile Analysis ◽  
Substrate Surface ◽  
Diamond Films ◽  
Diamond Powder ◽  
Hydrogen Atmosphere ◽  
Nucleation Density ◽  
Annealing Stage ◽  
Multistep Process ◽  
Degree Of Orientation

The growth of coalesced, highly oriented diamond films has been achieved on nickel substrates using a multistep process that consisted of (i) seeding the Ni surface with 0.5 μm diamond powder, (ii) annealing at 1100 °C in a hydrogen atmosphere, and (iii) growth at 900 °C in a mixture of hydrogen and 0.5% methane. Auger depth profile analysis of a sample quenched after the annealing stage showed the presence of significant amounts of carbon (6 at. %) close to the substrate surface and about 3 at.% deeper in the substrate. The loss of carbon into the substrate resulted in relatively low nucleation density. The addition of methane into the gas phase during the annealing stage proved very effective in compensating for the diffusion. An addition of 0.5% methane in the gas phase produced optimum results, as the nucleation density, orientation of diamond particles, and uniformity were substantially improved. Substrates nucleated under these conditions were grown out into coalesced, 30 μm thick films. Both (100) and (111) oriented films showed a high degree of orientation and Raman spectra obtained from these orientations showed intense and narrow diamond signature peaks with FWHM's of 5 and 8 cm-1, respectively.

Diffusion model for deposition of epitaxial GaAs layers prepared by the MOCVD method

1991 ◽  
Vol 56 (10) ◽  
pp. 2020-2029
Author(s):  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma ◽  
Rudolf Hladina
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Kinetic Model ◽  
Gas Phase ◽  
Substrate Surface ◽  
Deposition Process ◽  
Hydrogen Atmosphere ◽  
Epitaxial Gaas ◽  
Kinetics Of ◽  
Good Agreement

The authors proposed and treated quantitatively a kinetic model for deposition of epitaxial GaAs layers prepared by reaction of trimethylgallium with arsine in hydrogen atmosphere. The transport of gallium to the surface of the substrate is considered as the controlling process. The influence of the rate of chemical reactions in the gas phase and on the substrate surface on the kinetics of the deposition process is neglected. The calculated dependence of the growth rate of the layers on the conditions of the deposition is in a good agreement with experimental data in the temperature range from 600 to 800°C.

Seeding With a Diamond Suspension for Growth of Smooth Polycrystalline Diamond Surfaces

1996 ◽  
Vol 423 ◽  
Author(s):  
I. St. Omer ◽  
T. Stacy ◽  
E. M. Charlson ◽  
E. J. Charlson
Keyword(s):  
Surface Roughness ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Diamond Powder ◽  
Diamond Surface ◽  
Nucleation Density ◽  
Diamond Grit ◽  
Diamond Surfaces ◽  
Carrier Fluid

AbstractA number of techniques have been used to smooth polycrystalline diamond films. Recent work in substrate seeding with nanocrystalline diamond powder, alone or in a carrier fluid, has shown that diamond seeding improves nucleation density and reduces diamond surface roughness. In this work, silicon substrates were seeded using a commercially available waterbased 0.1 micrometer diamond polishing suspension. Growth was achieved using conventional hot-filament chemical vapor deposition (HFCVD). Films were characterized using optical microscopy, scanning electron microscopy (SEM), x-ray diffraction (XRD), and surface profilometry. The resulting diamond films exhibited well-faceted crystals, small grain size and minimal surface roughness. Additionally, the silicon substrate was chemically etched in order to permit examination of the backside of the diamond film. Results show that the diamond surface at the silicon-diamond interface is ultra-smooth. Comparison of the backside of these surfaces with those prepared using conventional diamond grit abrasion indicates that a significant improvement in surface quality is achieved using this diamond seeding technique.

Characterization of homoepitaxial diamond films by Electron microscopy

1991 ◽  
Vol 49 ◽  
pp. 880-881
Author(s):  
D.P. Malta ◽  
S.A. Willard ◽  
R.A. Rudder ◽  
G.C. Hudson ◽  
J.B. Posthill ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Surface Defects ◽  
Substrate Surface ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Large Degree ◽  
Rf Plasma ◽  
Semiconducting Diamond

Semiconducting diamond films have the potential for use as a material in which to build active electronic devices capable of operating at high temperatures or in high radiation environments. A major goal of current device-related diamond research is to achieve a high quality epitaxial film on an inexpensive, readily available, non-native substrate. One step in the process of achieving this goal is understanding the nucleation and growth processes of diamond films on diamond substrates. Electron microscopy has already proven invaluable for assessing polycrystalline diamond films grown on nonnative surfaces.The quality of the grown diamond film depends on several factors, one of which is the quality of the diamond substrate. Substrates commercially available today have often been found to have scratched surfaces resulting from the polishing process (Fig. 1a). Electron beam-induced current (EBIC) imaging shows that electrically active sub-surface defects can be present to a large degree (Fig. 1c). Growth of homoepitaxial diamond films by rf plasma-enhanced chemical vapor deposition (PECVD) has been found to planarize the scratched substrate surface (Fig. 1b).

Nucleation and selected area deposition of diamond by biased hot filament chemical vapor deposition

1995 ◽  
Vol 10 (2) ◽  
pp. 425-430 ◽  
Author(s):  
W. Zhu ◽  
F.R. Sivazlian ◽  
B.R. Stoner ◽  
J.T. Glass
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Substrate Surface ◽  
Chemical Vapor ◽  
Wire Mesh ◽  
Reactor Wall ◽  
Nucleation Density ◽  
Si Substrate ◽  
Diamond Nucleation ◽  
Hot Filament

This paper describes a process for uniformly enhancing the nucleation density of diamond films on silicon (Si) substrates via dc-biased hot filament chemical vapor deposition (HFCVD). The Si substrate was negatively biased and the tungsten (W) filaments were positively biased relative to the grounded stainless steel reactor wall. It was found that by directly applying such a negative bias to the Si substrate in a typical HFCVD process, the enhanced diamond nucleation occurred only along the edges of the Si wafer. This resulted in an extremely nonuniform nucleation pattern. Several modifications were introduced to the design of the substrate holder, including a metal wire-mesh inserted between the filaments and the substrate, in the aim of making the impinging ion flux more uniformly distributed across the substrate surface. With such improved growth system designs, uniform enhancement of diamond nucleation across the substrate surface was realized. In addition, the use of certain metallic wire mesh sizes during biasing also enabled patterned or selective diamond deposition.

scholarly journals The Transformation from (111) to (100): A Routine to Large-Scale Epitaxial Diamond

2020 ◽  
Author(s):  
Yang Wang ◽  
Weihua Wang ◽  
Shilin Yang ◽  
Jiaqi Zhu
Keyword(s):  
Large Scale ◽  
Diamond Films ◽  
Diamond Growth ◽  
Nucleation Density ◽  
Diamond Synthesis ◽  
First Principle ◽  
High Quality ◽  
First Principle Calculations ◽  
Large Size ◽  
Experimental Researches

Diamond is a material with excellent performances which attracts the attention from researchers for decades. Pt (111), owing to its catalytic activity on diamond synthesis, is regarded to be a candidate for diamond hetero-epitaxity, which can enhance nucleation density. Molten surface at diamond growth temperature can also improve mobility and aggregation capability of primitive nuclei. Generally, (100)-oriented is welcomed for the achivement of high quality and large size diamond, since the formation of defects and twins are prevented. First-principle calculations and experimental researches were carried out for the study of transformation of orientation. The transformation from {111} to {100}-oriented diamond has been observed on Pt (111) substrate, which can be promoted by the increase of carbon source concentration and substrate temperature. The process is energetic favorable, which may provides a way towards large-scale (100) diamond films.

Nanostructuring of diamond films using self-assembled nanoparticles

Open Physics ◽  
2009 ◽  
Vol 7 (2) ◽  
Author(s):  
Oleg Babchenko ◽  
Alexander Kromka ◽  
Karel Hruska ◽  
Miroslav Michalka ◽  
Jiri Potmesil ◽  
...  
Keyword(s):  
Plasma Etching ◽  
Self Assembly ◽  
Diamond Films ◽  
Diamond Powder ◽  
Gas Mixture ◽  
Assembly Strategy ◽  
Nano Structures ◽  
Mask Type ◽  
Different Types ◽  
Nano Rods

AbstractWe report the use of gold, nickel and diamond nanoparticles as a masking material for realization of diamond nano-structures by applying the dry plasma etching process. Applying low power plasma (100 W) in a gas mixture of CF4/O2 for 5 minutes results in a formation of three different types of diamond nanostructures, depending on the mask type material and particle size. Using of the Ni mask results in realization of diamond nano-rods, applying of the Au mask brings cauliflower-like structures, and using the diamond powder allows the production of irregular nano-structures. The main advance of the presented etching procedure is use of a self-assembly strategy where no lithographic steps are implemented.

Ultrahigh nucleation density for growth of smooth diamond films

1995 ◽  
Vol 66 (3) ◽  
pp. 311-313 ◽  
Author(s):  
G. S. Yang ◽  
M. Aslam
Keyword(s):  
Diamond Films ◽  
Nucleation Density

Evolution and properties of adherent diamond films with ultra high nucleation density deposited onto alumina

2005 ◽  
Vol 14 (2) ◽  
pp. 144-154 ◽  
Author(s):  
O. Ternyak ◽  
R. Akhvlediani ◽  
A. Hoffman
Keyword(s):  
Diamond Films ◽  
Nucleation Density

Aqueous leaching of ADOPT and standard UO2 spent nuclear fuel under H2 atmosphere

MRS Advances ◽  
2020 ◽  
Vol 5 (3-4) ◽  
pp. 167-175
Author(s):  
Alexandre Barreiro Fidalgo ◽  
Olivia Roth ◽  
Anders Puranen ◽  
Lena Z. Evins ◽  
Kastriot Spahiu
Keyword(s):  
Gas Phase ◽  
Nuclear Fuel ◽  
Preliminary Data ◽  
Spent Nuclear Fuel ◽  
Uranium Concentration ◽  
Hydrogen Atmosphere ◽  
Dissolution Behavior ◽  
Leaching Behavior ◽  
New Type ◽  
Failure Scenario

ABSTRACTLeaching results to compare the dissolution behavior of a new type of fuel with additives (Advanced Doped Pellet Technology, ADOPT) with standard UO2 fuel are presented. Both fuels were irradiated in the same assembly of a commercial boiling water reactor to a local burnup of ∼58 MWd/kgU. Fuel fragments are leached in simplified groundwater in two autoclaves under hydrogen atmosphere, representing conditions in a canister failure scenario resulting in water intrusion for a spent nuclear fuel repository. Preliminary results indicate the uranium concentration decreased to 3-4x10-8 M after 421 days, slightly above the solubility of amorphous UO2. Xe has been detected in the gas phase of both autoclaves. The concentration of Cs and I seems to gradually approach constant values, yet the redox sensitive elements continue to slowly increase with time. The preliminary data obtained supports the hypothesis that there is no major difference in leaching behavior between the two fuels.

Attempts to p-Dope Ultrananocrystalline Diamond Films in a Hot Filament Reactor

2006 ◽  
Vol 956 ◽  
Author(s):  
Paul William May ◽  
Matthew Hannaway
Keyword(s):  
Vapour Deposition ◽  
Film Growth ◽  
Substrate Surface ◽  
Diamond Films ◽  
Chemical Vapour ◽  
Grain Sizes ◽  
Ultrananocrystalline Diamond ◽  
The Individual ◽  
P Type ◽  
Hot Filament

ABSTRACTUltrananocrystalline diamond (UNCD) films have been deposited using hot filament chemical vapour deposition using Ar/CH4/H2 gas mixtures plus additions of B2H6 in an attempt to make p-type semiconducting films. With increasing additions of B2H6 from 0 to 40,000 ppm with respect to C, the film growth rate was found to decrease substantially, whilst the individual grain sizes increased from nm to μm. With 40,000 ppm of B2H6, crystals of boric oxide were found on the substrate surface, which slowly hydrolysed to boric acid on exposure to air. These results are rationalised using a model for UNCD growth based on competition for surface radical sites between CH3 and C atoms.

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