Geometric Model of CVD Mono-Crystalline Diamond Growth

2015 ◽  
Vol 730 ◽  
pp. 160-163
Author(s):  
Li Zhu Zhang ◽  
Fu Zhong Wang ◽  
Guang Tian

In order to describe the morphology of diamond films, we have developed a geometrical growth model which takes into account the displacement of the observed faces [1].We will see how to establish the topologies that are potentially accessible to CVD diamond growth.Lastly, we will present results showing the influence of the occurrence of certain crystalline faces on the film characteristics. From these results, we will show how the growth model and to establish a growth strategy aimed at obtaining large usable surface area crystals.

2015 ◽  
Vol 1728 ◽  
Author(s):  
Stefano Gay ◽  
Giacomo Reina ◽  
Ilaria Cianchetta ◽  
Emanuela Tamburri ◽  
Mariglen Angjellari ◽  
...  

ABSTRACTWe report here on the chemical methodologies that are being settled in our labs for the insertion in diamond of foreign atoms and consequent creation of fluorescent defects. The inclusion of Si, Cr, Ge, able to produce color centers, is directly obtained during the process of diamond synthesis by means of a CVD technique. The deposition of the diamond films takes place on substrates of different nature, treated following procedures specifically settled to control the insertion of the different species. The photoluminescence emission from a series of diamond samples grown on different substrates (Si, Ge and Ti) has been investigated and is discussed with reference to the morphological/structural features of the diamond phase and to the experimental procedures adopted for substrate preparation.


2008 ◽  
Vol 17 (7-10) ◽  
pp. 1067-1075 ◽  
Author(s):  
F. Silva ◽  
J. Achard ◽  
X. Bonnin ◽  
O. Brinza ◽  
A. Michau ◽  
...  

1996 ◽  
Vol 436 ◽  
Author(s):  
M. D. Drory

AbstractLarge residual stresses in diamond coatings may result in film failure through splitting, delamination and substrate failure. In addition, the CVD diamond growth environment may degrade the substrate mechanical properties. These issues are examined for diamond-coating of a tool steel alloy. Diamond growth was achieved on the steel substrate with the use of a titanium interlayer. Embrittlement of the Ti interlayer was not evident, however the substrate hardness was severely degraded.


Author(s):  
Dmitry V. Teteruk ◽  
Vitaly S. Bormashov ◽  
Sergey A. Tarelkin ◽  
Nikolay V. Kornilov ◽  
Nikolay V. Luparev ◽  
...  

CVD diamond grows on the all surfaces of the substrate, including the side faces. However, the diamond layer on side faces may be undesirable. We proposed and developed the method to suppress the CVD diamond growth on the side faces using silicon wells. The optimal geometric dimensions of the wells were determined. The studies of the structural quality of the CVD diamond films were carried out.


1995 ◽  
Vol 383 ◽  
Author(s):  
D. F. Bahr ◽  
J..C. Nelson ◽  
D. Zhuang ◽  
E. Pfender ◽  
J. Heberlein ◽  
...  

ABSTRACTPoor adhesion of diamond films limits the use of CVD diamond films as coatings for cutting tools. The adhesion of these films is limited by stresses in the film caused by thermal expansion mismatch between the substrate and the film and by voids present at the interface due to the morphology of the crystal growth. A three step process of making diamond composite films has been developed, involving nucleation of individual diamonds on the substrate, electroplating a metal binder in the voids between the crystals, and lastly growing a complete film over the composite layer. The metal binder acts both to fill the voids at the interface and to absorb energy during fracture processes at the interface. Diamond growth was performed in a DC Triple Torch reactor using a mixture of methane and hydrogen with a molybdenum substrate. Measurements to determine the amount of improvement of the film adhesion have been performed. These tests include indentations using conventional hardness testing equipment and four point bend tests with the film in tension and compression. A correlation is shown between the plastic zone of the substrate and the area of the film which delaminated during indentation. Bend tests with the film in tension did not delaminate the film, instead the film underwent intergranular fracture. Bend tests in compression act similarly to pile up around an indentation, and cause film delamination. Residual stress measurements in the single step film show a compressive stress of 650 MPa.


2005 ◽  
Vol 12 (04) ◽  
pp. 499-504
Author(s):  
SHA LIU ◽  
ZHI-MING YU ◽  
DAN-QING YI

It is known that in the condition of chemical vapor deposition (CVD) diamond process, molybdenum is capable of forming carbide known as the "glue" which promotes growth of the CVD diamond, and aids its adhesion by (partial) relief of stresses at the interface. Furthermore, the WC grains are reaction bonded to the Mo 2 C phase. Therefore, molybdenum is a good candidate material for the intermediate layer between WC–Co substrates and diamond coatings. A molybdenum intermediate layer of 1–3 μm thickness was magnetron sputter-deposited on WC/Co alloy prior to the deposition of diamond coatings. Diamond films were deposited by hot filament chemical vapor deposition (HFCVD). The chemical quality, morphology, and crystal structure of the molybdenum intermediate layer and the diamond coatings were characterized by means of SEM, EDX, XRD and Raman spectroscopy. It was found that the continuous Mo intermediate layer emerged in spherical shapes and had grain sizes of 0.5–1.5 μm after 30 min sputter deposition. The diamond grain growth rate was slightly slower as compared with that of uncoated Mo layer on the WC–Co substrate. The morphologies of the diamond films on the WC–Co substrate varied with the amount of Mo and Co on the substrate. The Mo intermediate layer was effective to act as a buffer layer for both Co diffusion and diamond growth.


Micromachines ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 719
Author(s):  
Xiaoju Li ◽  
Lianlong He ◽  
Yuanshi Li ◽  
Qiaoqin Yang

This article presents an overview of the research in chemical vapor deposition (CVD) diamond films on steel substrates. Since the steels are the most commonly used and cost-effective structural materials in modern industry, CVD coating diamond films on steel substrates are extremely important, combining the unique surface properties of diamond with the superior toughness and strength of the core steel substrates, and will open up many new applications in the industry. However, CVD diamond deposition on steel substrates continues to be a persistent problem. We go through the most relevant results of the last two and a half decades, including recent advances in our group. This review discusses the essential reason of the thick catalytic graphite interlayer formed on steel substrates before diamond deposition. The high carbon diffusion in iron would induce severe internal carburization, and then voluminous graphite precipitated from the substrate. In order to hinder the catalytic graphite formation, various methods have been applied for the adherent diamond film deposition, such as pre-imposed various interlayers or multi-interlayers, special controls of the deposition process, the approaches of substrate alloying and so on. We found that adherent diamond films can be directly deposited on Al alloying steel substrates, and then the role of Al alloying element was examined. That is a thin dense amorphous alumina sublayer in situ formed on the alloying substrate, which played a critical role in preventing the formation of graphite phase and consequently enhancing diamond growth and adhesion. The mechanism of Al alloying suggests that the way used to improve hot corrosion resistance is also applicable. Then, some of the hot corrosion resistance methods, such as aluminizing, siliconizing, and so on, which have been used by some researchers examining CVD diamond films on steel substrates, are reviewed. Another way is to prepare diamond-like carbon (DLC) films on steel substrates at low temperature, and then the precipitated graphite from the internal carburization can be effectively avoided. In addition, based on some new findings, the understanding of the diamond nucleation and metastable growth is discussed.


Author(s):  
Qiang Lin ◽  
Sulin Chen ◽  
Zhe Ji ◽  
Zhewei Huang ◽  
Zhinan Zhang ◽  
...  

1998 ◽  
Vol 527 ◽  
Author(s):  
Armando Netto ◽  
Michael Frenklach

ABSTRACTDiamond films are of interest in many practical applications but the technology of producing high-quality, low-cost diamond is still lacking. To reach this goal, it is necessary to understand the mechanism underlying diamond deposition. Most reaction models advanced thus far do not consider surface diffusion, but recent theoretical results, founded on quantum-mechanical calculations and localized kinetic analysis, highlight the critical role that surface migration may play in growth of diamond films. In this paper we report a three-dimensional time-dependent Monte Carlo simulations of diamond growth which consider adsorption, desorption, lattice incorporation, and surface migration. The reaction mechanism includes seven gas-surface, four surface migration, and two surface-only reaction steps. The reaction probabilities are founded on the results of quantum-chemical and transition-state-theory calculations. The kinetic Monte Carlo simulations show that, starting with an ideal {100}-(2×1) reconstructed diamond surface, the model is able to produce a continuous film growth. The smoothness of the growing film and the developing morphology are shown to be influenced by rate parameter values and by deposition conditions such as temperature and gaseous species concentrations.


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