Diamond Growth Chemistry During Atmospheric-Pressure Plasma Cvd

1995 ◽  
Vol 416 ◽  
Author(s):  
S. L. Girshick ◽  
J. W. Lindsay
Keyword(s):  
Atmospheric Pressure ◽  
Linear Growth ◽  
Diamond Films ◽  
Atmospheric Pressure Plasma ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Diamond Growth ◽  
Gas Chromatograph ◽  
Plasma Cvd ◽  
Flow Geometry

ABSTRACTDiamond films were deposited by chemical vapor deposition using a radio- frequency induction plasma operating at 130 torr. Linear growth rates of polycrystalline diamond films ranged from 18 to 37 μm h-1. For a fixed substrate temperature of 1000°C the input methane-hydrogen ratio was varied from 2% to 10%. Over this range the resulting film morpologies changed from faceted ball-like structures to well-faceted diamond, then to non-faceted balls, and for the well- faceted films increases in methane-hydrogen ratio caused the film texture to shift toward the <100> direction. During these experiments gas sampled through an orifice in the center of the substrate was delivered to a gas chromatograph for measurement of stable hydrocarbon species. As the input methane-hydrogen ratio was increased the measured methane-acetylene ratio decreased. The gas chromatograph measurements showed marked differences from measurements made for an RF reactor with somewhat different flow geometry operating at atmospheric pressure.

Diamond Growth on (a) Large Mo Cylinders at 30 Torr and (b) Flat Mo at One Atmospheric Pressure of H2 and CH4

1996 ◽  
Vol 441 ◽  
Author(s):  
R. Ramesham ◽  
M. F. Rose
Keyword(s):  
Atmospheric Pressure ◽  
Microwave Plasma ◽  
Diamond Films ◽  
Polycrystalline Diamond ◽  
Diamond Growth ◽  
Single Filament ◽  
Active Length ◽  
Microwave Plasma Cvd ◽  
Hot Filament ◽  
First Time

Abstract(a) Polycrystalline diamond films have been grown on cylindrical Mo substrates by hot filament and microwave plasma CVD techniques using a gas mixture of hydrogen and methane. A single hot tungsten filament has been used to demonstrate the growth of adherent diamond films on large cylinders. To our knowledge this is the first report on such large cylindrical substrate (area: 41 cm2 ) using a single filament of active length of 3.75 cm. (b) Polycrystalline diamond films have been deposited by hot-filament technique for the first time using methane and hydrogen at an atmospheric pressure of hydrogen on flat substrates. The diamond growth has been performed at various pressures ranging from 34.5 to 750 Torr. The as-deposited films were analyzed by SEM and Raman to determine morphology and chemical nature, respectively.A. Growth of Diamond Film on Molybdenum Cylinders

Fracture strength measurement of filament assisted CVD polycrystalline diamond films

1992 ◽  
Vol 7 (6) ◽  
pp. 1432-1437 ◽  
Author(s):  
G.F. Cardinale ◽  
C.J. Robinson
Keyword(s):  
Fracture Strength ◽  
Microwave Plasma ◽  
Natural Diamond ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
High Strength ◽  
Coarse Grained ◽  
Diamond Growth ◽  
Growth Surface

The fracture strength of polycrystalline diamond films deposited by filament assisted chemical vapor deposition in the thickness range of 3.5 to 160 μm is investigated. Using a burst pressure technique, the fracture strengths of circular diamond film specimens are calculated. An average fracture strength of 730 MPa for nine samples was computed. This value is in good agreement with published strengths of microwave plasma deposited diamond films, comparable to other high strength materials, and within an order of magnitude of the fracture strength of bulk natural diamond. The average fracture strength of the fine-grained substrate interface appears consistently higher than that of the coarse-grained diamond growth surface.

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.

On the role of penetration twins in the morphological development of vapor-grown diamond films

1994 ◽  
Vol 9 (7) ◽  
pp. 1839-1849 ◽  
Author(s):  
M.A. Tamor ◽  
M.P. Everson
Keyword(s):  
Diamond Films ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Growth Conditions ◽  
Diamond Growth ◽  
Morphological Development ◽  
Competitive Growth ◽  
Full Spectrum ◽  
Major Controlling Factor ◽  
Diamond Crystallite

Polycrystalline diamond films may be produced by chemical vapor deposition (CVD) with morphologies ranging from multimicron crystallites with well-defined facets and texture to nanocrystalline “cauliflower” nodules. While previous efforts to connect diamond film “quality” to growth conditions focus on competitive growth of non-diamond phases, we propose that twinning is a major controlling factor. We use geometric arguments to define the conditions under which a given twin can outgrow and bury the “parent” face on which it originated. We then show how the full spectrum of diamond crystallite shapes and film morphologies can be explained in terms of penetration twins without reference to the actual mechanistics of diamond growth.

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).

Examination of the material properties and performance of thin-diamond film cutting tool inserts produced by arc-jet and hot filament chemical vapor deposition

1996 ◽  
Vol 11 (7) ◽  
pp. 1765-1775 ◽  
Author(s):  
James M. Olson ◽  
Michael J. Dawes
Keyword(s):  
Wear Resistance ◽  
Chemical Vapor Deposition ◽  
Diamond Film ◽  
Vapor Deposition ◽  
Cutting Tool ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
And Performance ◽  
Hot Filament

Thin diamond film coated WC-Co cutting tool inserts were produced using arc-jet and hot-filament chemical vapor deposition. The diamond films were characterized using SEM, XRD, and Raman spectroscopy to examine crystal structure, fracture mode, thickness, crystalline orientation, diamond quality, and residual stress. The performance of the tools was evaluated by comparing the wear resistance of the materials to brazed polycrystalline diamond-tipped cutting tool inserts (PCD) while machining A390 aluminum (18% silicon). Results from the experiments carried out in this study suggest that the wear resistance of the thin diamond films is primarily related to the grain boundary strength, crystal orientation, and the density of microdefects in the diamond film.

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