Mass Transport Effects In Selectively Deposited Diamond Thin Films

1995 ◽  
Vol 416 ◽  
Author(s):  
Michael C. Kwan ◽  
Karen K. Gleason
Keyword(s):  
Growth Rate ◽  
Gas Phase ◽  
Surface Reaction ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
Scanning Electron Micrographs ◽  
First Order ◽  
Reaction Coefficient ◽  
Hot Filament ◽  
Order Surface

ABSTRACTIn order to study the effects of gas phase transport on the growth of hot-filament chemical vapor deposited (HFCVD) diamond, crystallites were selectively grown on a pre-nucleated, oxygen plasma patterned silicon wafer. Growth rate differences across the substrate were observed from scanning electron micrographs. The deposition system was then modeled with a three dimensional finite difference scheme that employed gas phase diffusion of a single growth limiting species from the hot filament to the surface coupled with a first order surface reaction. The variations in the predicted gas phase concentration directly above the surface were adjusted to match the observed growth rate differences through the Dahmk6hler number which was then used to calculate a first order surface reaction coefficient. This value was compared to published reaction coefficients for the abstraction of a surface H-atom by a gas-phase H-atom.

A polycentric growth model of gallium arsenide epitaxial layers from the gas phase with simultaneous diffusion, adsorption and chemical reaction

1988 ◽  
Vol 53 (12) ◽  
pp. 2995-3013
Author(s):  
Emerich Erdös ◽  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma
Keyword(s):  
Growth Rate ◽  
Gallium Arsenide ◽  
Epitaxial Growth ◽  
Gas Phase ◽  
Surface Reaction ◽  
Quantitative Description ◽  
The Other ◽  
Rate Equations ◽  
Impact Interaction ◽  
Partial Pressures

For a quantitative description of the epitaxial growth rate of gallium arsenide, two models are proposed including two rate controlling steps, namely the diffusion of components in the gas phase and the surface reaction. In the models considered, the surface reaction involves a reaction triple - or quadruple centre. In both models three mechanisms are considered which differ one from the other by different adsorption - and impact interaction of reacting particles. In every of the six cases, the pertinent rate equations were derived, and the models have been confronted with the experimentally found dependences of the growth rate on partial pressures of components in the feed. The results are discussed with regard to the plausibility of individual mechanisms and of both models, and also with respect to their applicability and the direction of further investigations.

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.

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

2016 ◽  
Vol 869 ◽  
pp. 721-726 ◽  
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.

Kinetics And Morphology Of Homoepitaxial Cvd Growth On Diamond (100) And (111)

1995 ◽  
Vol 416 ◽  
Author(s):  
R. E. Rawles ◽  
W. G. Morris ◽  
M. P. D’Evelyn
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Chemical Vapor ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Arrhenius Behavior ◽  
Oriented Growth ◽  
Relative Growth Rates ◽  
Cvd Growth ◽  
Hot Filament

ABSTRACTGrowth rates for homoepitaxy of diamond (100) and (111) by hot-filament chemical vapor deposition were measured via in situ Fizeau interferometry and the surface morphologies were subsequently characterized by atomic force microscopy (AFM). (100)-oriented growth from 0.5% CH4 in H2 exhibited pure Arrhenius behavior, with an activation energy of 17±1 kcal/mol, up to a substrate temperature of 1100°C. Addition of oxygen to the feed gas resulted in an increased growth rate below 900°C, a maximum growth rate between 900 and 1000°C, and etching (of diamond) above 1050 - 1100°C. However, the presence of oxygen apparently had less effect on the surface morphology than did the (100)-to-(111) growth rate parameter α, determined directly from the relative growth rates of (100) and (111) substrates mounted side by side. During homoepitaxial growth from 0.5% CH4 in H2 at 875°C of ca. 1-micron-thick films,α = was 2.2 without oxygen and 1.3 for growth with 0.14% O2. The (100) film grown with α = 2.2 was quite smooth, while that with α = 1.3 was covered by numerous hillocks and penetration twins. AFM analysis revealed surprisingly little difference between the (111) films despite the considerable difference in α. Implications of these results for the growth mechanism are discussed.

The thermal decomposition of cyclobutane-1,2-dione

1985 ◽  
Vol 63 (11) ◽  
pp. 2945-2948 ◽  
Author(s):  
J.-R. Cao ◽  
R. A. Back
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Vapor Pressure ◽  
Gas Phase ◽  
Rate Constant ◽  
Surface Reaction ◽  
Order Rate Constant ◽  
Reaction Vessel ◽  
Arrhenius Parameters ◽  
First Order

The thermal decomposition of cyclobutane-1,2-dione has been studied in the gas phase at temperatures from 120 to 250 °C and pressures from 0.2 to 1.5 Torr. Products were C2H4 + 2CO, apparently formed in a simple unimolecular process. The first-order rate constant was strongly pressure dependent, and values of k∞ were obtained by extrapolation of plots of 1/k vs. 1/p to1/p = 0. Experiments in a packed reaction vessel showed that the reaction was enhanced by surface at the lower temperatures. Arrhenius parameters for k∞, corrected for surface reaction, were log A (s−1) = 15.07(±0.3) and E = 39.3(±2) kcal/mol. This activation energy seems too low for a biradical mechanism, and it is suggested that the decomposition is probably a concerted process. The vapor pressure of solid cyclobutane-1,2-dione was measured at temperatures from 22 to 62 °C and a heat of sublimation of 13.1 kcal/mol was estimated.

Simulation of Substrate Temperature Distribution in Diamond Films Growth on Cemented Carbide Inserts by Hot Filament CVD

2007 ◽  
Vol 10-12 ◽  
pp. 864-868 ◽  
Author(s):  
Wei Zuo ◽  
Bin Shen ◽  
Fang Hong Sun ◽  
Ming Chen
Keyword(s):  
Temperature Distribution ◽  
Three Dimensional ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Deposition Parameters ◽  
Dimensional Finite Element ◽  
Simulation Results ◽  
Three Dimensional Finite Element ◽  
Hot Filament ◽  
Carbide Inserts

Three-dimensional finite element simulations were used to investigate the influences of various hot filaments and other deposition parameters on the temperature field of substrates which affect significantly the growth and quality of diamond films by hot filament chemical vapor deposition (HFCVD) and based on the simulation results, the optimum position for diamond deposition was found. In the experiment, six cemented tungsten carbide inserts were used as substrates and placed on the workbench in the CVD reactor to deposit diamond films. According to the temperature distribution on substrates measured by thermocouple fixed in CVD reactor, the simulations were validated and the optimum arrangement of substrates was established from the simulation results. In addition, the simulation model was altered to optimize the process parameters of HFCVD deposition, and an improved process of depositing diamond films with high quality was obtained in order to achieve the great surface morphology, which laid the foundation of developing a new method to arrange the substrates in the CVD reactor for depositing diamond films.

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

1995 ◽  
Vol 10 (2) ◽  
pp. 431-435 ◽  
Author(s):  
Kazunori Tamaki ◽  
Yoshikazu Nakamura ◽  
Yoshihisa Watanabe ◽  
Shigekazu Hirayama
Keyword(s):  
Growth Rate ◽  
Chemical Vapor Deposition ◽  
Amorphous Carbon ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Bonding State ◽  
Diamond Particles ◽  
Intermediate Layers ◽  
Hot Filament ◽  
Hydrogenated Amorphous

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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