Growth of Diamond Anvils for High-Pressure Research by Chemical Vapor Deposition

1997 ◽  
Vol 499 ◽  
Author(s):  
Andrew Israel ◽  
Yogesh K. Vohra
Keyword(s):  
High Pressure ◽  
Chemical Vapor Deposition ◽  
High Temperature ◽  
Growth Rates ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Diamond Growth ◽  
High Pressure High Temperature ◽  
Single Crystal Diamond ◽  
Diamond Anvils

ABSTRACTGem quality diamond crystals are employed as anvils in high-pressure diamond cell research. Homoepitaxial growth experiments by microwave plasma-assisted chemical vapor deposition (MPCVD) have produced 1.76 mm (diameter) by 0.65 mm (thickness) sized diamonds. We report fundamental studies on diamond growth rate and quality as a function of reactor pressure and methane concentration, in a hydrogen plasma. By varying the growth conditions, large, single crystal diamond can be produced, which is ideal for manufacturing high pressure anvils.Traditional high pressure, high temperature (HPHT) techniques for production of synthetic diamond anvils are extremely expensive and chemical vapor deposition (CVD) provides an economically viable alternative. We report diamond growth rates up to 0.32 mg/hr, which are comparable to HPHT growth rates, and crystal quality approaching that of gem diamond. When perfected, diamond anvils produced from chemical vapor deposition methods could replace those manufactured by high pressure, high temperature synthesis.

Composite chemical vapor deposition diamond anvils for high-pressure/high-temperature experiments

2009 ◽  
Vol 29 (2) ◽  
pp. 317-324 ◽  
Author(s):  
Chang-Sheng Zha ◽  
Szczesny Krasnicki ◽  
Yu-Fei Meng ◽  
Chih-Shiue Yan ◽  
Joseph Lai ◽  
...  
Keyword(s):  
High Pressure ◽  
Chemical Vapor Deposition ◽  
High Temperature ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Diamond ◽  
High Pressure High Temperature ◽  
Diamond Anvils

Role of nitrogen in the homoepitaxial growth on diamond anvils by microwave plasma chemical vapor deposition

2007 ◽  
Vol 22 (4) ◽  
pp. 1112-1117 ◽  
Author(s):  
Wei Qiu ◽  
Yogesh K. Vohra ◽  
Samuel T. Weir
Keyword(s):  
Growth Rate ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Diamond Growth ◽  
Plasma Chemical ◽  
Plasma Chemical Vapor Deposition ◽  
Homoepitaxial Growth ◽  
Diamond Anvils

The catalytic effect of nitrogen during the homoepitaxial diamond growth on a diamond anvil was investigated using isotopically enriched carbon-13 methane in a feed-gas mixture in a microwave plasma chemical vapor deposition reactor. The use of isotopically enriched carbon-13 allows us to precisely measure the film thickness in this homoepitaxial growth process by Raman spectroscopy. It is found that the addition of 0.4 sccm of nitrogen to an H2/CH4/O2 gas-phase mixture increases the growth rate by a factor of 2.3. This enhanced growth rate with the addition of trace amounts of nitrogen allows for a quick encapsulation of embedded sensors in the designer diamond anvils and is a key control parameter in the fabrication process. Photoluminescence spectroscopy reveals nitrogen-vacancy defect centers in the high-growth-rate diamonds. Atomic force microscopy reveals dramatic changes in the surface microstructure as is indicated by a total loss of step-flow growth morphology on the addition of nitrogen in the plasma.

scholarly journals Unusual Dependence of the Diamond Growth Rate on the Methane Concentration in the Hot Filament Chemical Vapor Deposition Process

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 426
Author(s):  
Byeong-Kwan Song ◽  
Hwan-Young Kim ◽  
Kun-Su Kim ◽  
Jeong-Woo Yang ◽  
Nong-Moon Hwang
Keyword(s):  
Growth Rate ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Methane Concentration ◽  
Chemical Vapor ◽  
Diamond Growth ◽  
Lower Growth ◽  
Filament Temperature ◽  
Diamond Phase ◽  
Hot Filament

Although the growth rate of diamond increased with increasing methane concentration at the filament temperature of 2100 °C during a hot filament chemical vapor deposition (HFCVD), it decreased with increasing methane concentration from 1% CH4 –99% H2 to 3% CH4 –97% H2 at 1900 °C. We investigated this unusual dependence of the growth rate on the methane concentration, which might give insight into the growth mechanism of a diamond. One possibility would be that the high methane concentration increases the non-diamond phase, which is then etched faster by atomic hydrogen, resulting in a decrease in the growth rate with increasing methane concentration. At 3% CH4 –97% H2, the graphite was coated on the hot filament both at 1900 °C and 2100 °C. The graphite coating on the filament decreased the number of electrons emitted from the hot filament. The electron emission at 3% CH4 –97% H2 was 13 times less than that at 1% CH4 –99% H2 at the filament temperature of 1900 °C. The lower number of electrons at 3% CH4 –97% H2 was attributed to the formation of the non-diamond phase, which etched faster than diamond, resulting in a lower growth rate.

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