Effect of hydrogenated amorphous carbon films on nucleation of diamond particles by hot-filament chemical vapor deposition

To enhance a nucleation rate of diamond particles, hydrogenated amorphous carbon (a-C: H) intermediate layers have been formed by radio frequency plasma chemical vapor deposition (CVD) on silicon substrates prior to diamond deposition by hot filament CVD, and the effect of a-C: H intermediate layers on the nucleation and growth rate of diamond particles is studied by varying the thickness of a-C: H films. It is found that diamond particles are well synthesized on thin a-C: H intermediate layers and the nucleation density and growth rate are decreased with increasing the thickness of a-C: H films. Atomic force microscope observations show that a-C: H intermediate layers with rough surface are more effective than the smooth surface for diamond synthesis. Raman spectroscopy shows that the bonding state of carbon atoms in a-C: H films does not change by varying the thickness of a-C: H films. It is proposed that diamond nucleation is affected by the surface morphology rather than the bonding state of carbon atoms in a-C: H films.

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NITROGEN INCORPORATED HYDROGENATED AMORPHOUS CARBON THIN FILMS DEPOSITED BY MICROWAVE SURFACE-WAVE PLASMA CHEMICAL VAPOR DEPOSITION

International Journal of Modern Physics B ◽

10.1142/s0217979209048559 ◽

2009 ◽

Vol 23 (09) ◽

pp. 2159-2165 ◽

Cited By ~ 2

Author(s):

SUDIP ADHIKARI ◽

MASAYOSHI UMENO

Keyword(s):

Thin Films ◽

Chemical Vapor Deposition ◽

Surface Wave ◽

Amorphous Carbon ◽

Vapor Deposition ◽

Chemical Vapor ◽

Plasma Chemical ◽

Hydrogenated Amorphous Carbon ◽

Plasma Chemical Vapor Deposition ◽

Hydrogenated Amorphous

Nitrogen incorporated hydrogenated amorphous carbon (a-C:N:H) thin films have been deposited by microwave surface-wave plasma chemical vapor deposition on silicon and quartz substrates, using helium, methane and nitrogen ( N 2) as plasma source. The deposited a-C:N:H films were characterized by their optical, structural and electrical properties through UV/VIS/NIR spectroscopy, Raman spectroscopy, atomic force microscope and current-voltage characteristics. The optical band gap decreased gently from 3.0 eV to 2.5 eV with increasing N 2 concentration in the films. The a-C:N:H film shows significantly higher electrical conductivity compared to that of N 2-free a-C:H film.

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

Materials ◽

10.3390/ma14020426 ◽

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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Effect of Argon during Diamond Deposition by Hot Filament Chemical Vapor Deposition

Materials Science Forum ◽

10.4028/www.scientific.net/msf.869.721 ◽

2016 ◽

Vol 869 ◽

pp. 721-726 ◽

Cited By ~ 1

Author(s):

Divani C. Barbosa ◽

Ursula Andréia Mengui ◽

Mauricio R. Baldan ◽

Vladimir J. Trava-Airoldi ◽

Evaldo José Corat

Keyword(s):

Growth Rate ◽

Chemical Vapor Deposition ◽

Vapor Deposition ◽

Chemical Vapor ◽

Diamond Growth ◽

Gas Mixture ◽

X Ray Diffraction ◽

Hot Filament ◽

Argon Content

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.

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