Hot filament assisted diamond growth at low temperatures with oxygen addition

1997 ◽  
Vol 12 (5) ◽  
pp. 1344-1350 ◽  
Author(s):  
Z. Li Tolt ◽  
L. Heatherly ◽  
R. E. Clausing ◽  
C. S. Feigerle

Addition of a small amount of oxygen to the CH4 and H2 feed gas permits hot filament assisted chemical vapor deposition (HFCVD) of diamond at significantly lower filament and substrate temperatures. The former can be reduced to as low as 1400 °C and the latter to 450 °C. The amount of oxygen required is much lower than what has been used in most studies of the oxygen effect. For each CH4%, there is a narrow window in the O/C ratio, where diamond can be deposited at low temperature. This window shifts to higher O/C ratios as the CH4% increases and expands with increases in filament temperature. The effect of changing substrate and filament temperatures on growth rate and film quality are often not consistent with previous experiences with HFCVD of diamond. Increasing the filament temperature does not always improve the growth rate and film quality, and the non-diamond carbon content in the film is dramatically reduced at lower substrate temperatures. Optimum conditions were found that gave reasonable growth rates (∼0.5 μm/h) with high film quality at filament temperatures below 1750 °C and substrate temperatures below 600 °C. With these reductions in operating temperatures, power consumption can be significantly reduced and the filament lifetime extended indefinitely.

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 426
Author(s):  
Byeong-Kwan Song ◽  
Hwan-Young Kim ◽  
Kun-Su Kim ◽  
Jeong-Woo Yang ◽  
Nong-Moon Hwang

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.


2016 ◽  
Vol 869 ◽  
pp. 721-726 ◽  
Author(s):  
Divani C. Barbosa ◽  
Ursula Andréia Mengui ◽  
Mauricio R. Baldan ◽  
Vladimir J. Trava-Airoldi ◽  
Evaldo José Corat

The effect of argon content upon the growth rate and the properties of diamond thin films grown with different grains sizes are explored. An argon-free and argon-rich gas mixture of methane and hydrogen is used in a hot filament chemical vapor deposition reactor. Characterization of the films is accomplished by scanning electron microscopy, Raman spectroscopy and high-resolution x-ray diffraction. An extensive comparison of the growth rate values and films morphologies obtained in this study with those found in the literature suggests that there are distinct common trends for microcrystalline and nanocrystalline diamond growth, despite a large variation in the gas mixture composition. Included is a discussion of the possible reasons for these observations.


1995 ◽  
Vol 10 (11) ◽  
pp. 2685-2688 ◽  
Author(s):  
Qijin Chen ◽  
Zhangda Lin

Diamond film was synthesized on thin Ti wafers (as thin as 40 μm) via hot filament chemical vapor deposition (HFCVD). The hydrogen embrittlement of the titanium substrate and the formation of a thick TiC interlayer were suppressed. A very low pressure (133 Pa) was employed to achieve high-density rapid nucleation and thus to suppress the formation of TiC. Oxygen was added to source gases to lower the growth temperature and therefore to slow down the hydrogenation of the thin Ti substrate. The role of the very low pressure during nucleation is discussed, providing insight into the nucleation mechanism of diamond on a titanium substrate. The as-grown diamond films were characterized by scanning electron microscopy (SEM), Raman spectroscopy, and x-ray analysis.


1996 ◽  
Vol 11 (3) ◽  
pp. 694-702 ◽  
Author(s):  
S. W. Reeve ◽  
W. A. Weimer ◽  
D. S. Dandy

Based on results from chemical kinetic model calculations, a method to improve diamond film growth in a dc arcjet chemical vapor deposition reactor has been developed. Introducing the carbon source gas (CH4) into an Ar/H2 plasma in close proximity to the substrate produced diamond films exhibiting simultaneous improvements in quality and mass deposition rates. These improvements result from a reduced residence time of the methane in the plasma which inhibits the hydrocarbon chemistry in the gas from proceeding significantly beyond methyl radical production prior to encountering the substrate. Improvements in growth rate were modest, increasing by only a factor of two. Optical emission actinometry measurements indicate that the flux of atomic hydrogen across the stagnation layer to the substrate is mass diffusion limited. Since diamond growth depends upon the flux of atomic H to the substrate, these results suggest that under the conditions examined here, a low atomic H flux to the substrate poses an upper limit on the attainable diamond growth rate.


1989 ◽  
Vol 165 ◽  
Author(s):  
B. Anthony ◽  
T. Hsu ◽  
L. Breaux ◽  
S. Banerjee ◽  
A. Tasch

AbstractIn this paper the reaction kinetics of Remote Plasma-enhanced Chemical Vapor Deposition (RPCVD) are investigated. Growth rate characterization has been performed for substrate temperatures of 220 – 400°C, r-f powers from 4 – 8 W, and silane flow rates of 10 – 30 sccm. Growth rate has been found to increase exponentially with r-f power, which is, as yet, unexplained. An approximate square root dependence of growth rate on silane partial pressure agrees with the theory of Claasen et. Al for Chemical Vapor Deposition (CVD) of silicon from silane with an inert carrier gas. From an Arrhenius plot of the temperature dependence of growth rate, we note a change of slope at ∼300°C which we have attributed to the behavior of hydrogen at the silicon surface.


2011 ◽  
Vol 20 (5-6) ◽  
pp. 641-650 ◽  
Author(s):  
Qiuping Wei ◽  
Michael N.R. Ashfold ◽  
Yu. A. Mankelevich ◽  
Z.M. Yu ◽  
P.Z. Liu ◽  
...  

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