Chemical vapour deposition reactor

FIGURE 3.10 (a) Chemical-vapour deposition reactor (b) cross section of a 100 pm-thick CVD diamond film grown by DC arc jet. The columnar nature of the growth is evident, as is the increase in film quality and grain size with growth time. (Courtesy of Dr. Paul May and Prof. Mike Ashfold, Bristol University.)... 

Hitehman ML, Kane J, Widmer AE (1979) Poly silicon growth kinetics in a low pressure chemical vapour deposition reactor. Thin Solid Films 59 231-247... 

A new preparation method is described to synthesize porous silicon carbide. It comprises the catalytic conversion of preformed activated carbon (extrudates or granulates) by reacting it with hydrogen and silicon tetrachloride. The influence of crucial convoaion parameters on support properties is discussed for the SiC synthesis in a ftxed bed and fluidized bed chemical vapour deposition reactor. The surface area of the obtained SiC ranges ftiom 30 to 80 m /g. The metal support interaction (MSI) and metal support stability (MSS) of Ni/SiC catalysts are compared with that of conventional catalyst supports by temperature programmed reduction. It is shown that a Ni/SiC catalyst shows a considnable Iowa- MSI than Ni/Si(>2- and Ni/Al203-catalysts. A substantially improved MSS is observed an easily reducible nickel species is retained on the SiC surface after calcination at 1273 K. 

In practical applications, gas-surface etching reactions are carried out in plasma reactors over the approximate pressure range 10 -1 Torr, and deposition reactions are carried out by molecular beam epitaxy (MBE) in ultrahigh vacuum (UHV below 10 Torr) or by chemical vapour deposition (CVD) in the approximate range 10 -10 Torr. These applied processes can be quite complex, and key individual reaction rate constants are needed as input for modelling and simulation studies—and ultimately for optimization—of the overall processes. 

Pai, M. P., Musale, D. V. and Kshirsagar, S. T. (1998), Low-pressure chemical vapour deposition of diamond films in a radio-frequency plasma-assisted hot-filament reactor. Diam. Relat. Mater., 7(10) 1526-1533. 

Foundamentals of chemical vapour deposition in hot wall reactors, Huttinger, 2003 [150]... 

Huttinger KJ (2003) Foundamentals of chemical vapour deposition in hot wall reactors. In Dlhaes P (ed) Fibres and composites. Taylor Francis, London, pp75-86... 

A reaction chamber, also called a reactor, is the key subsystem of a CVD system, in which a chemical vapour deposition process takes place. In general a reaction chamber consists of the following parts as shown in Figure 3.12 ... 

Besides the nitrogen contamination due to pollution of the carrier gas, the diamond films obtained by chemical vapour deposition (CVD) are usually contaminated with silicon. This contamination originates from the plasma etching of the silica walls of the reactor and of the commonly used silicon substrates [37]. 

In Chemical vapour deposition (CVD) process, a chemical reaction involving a metal complex in the gas phase is performed at a controlled temperature and the produced metal deposits as a thin film by nucleation and growth on the substrate [69]. The deposition takes place on the hot substrate positioned in the CVD reactor. As in the case of PVD technique, the reaction temperature can be reached either by resistive heating of the substrate or by other heating sources [70]. 

Galuszka J, Giddings T (2011) Silica membranes-preparation by chemical vapour deposition and characteristics. In Basile A, Gallucci F (eds) Membranes for membrane reactors preparation, optimization and selection. Chap 12. Wiley, New York (in press)... 

J. Galuszka and T. Giddings, Sihca membranes-preparation by chemical vapour deposition and characteristics, in Membranes for Membrane Reactors Preparation, Optimization and Selection, ed. A. Basile, Wiley, Chapter 12. Wiley, 2011, ISBN 978-0-470-74652-3. 

Porous metal membranes are commercially available in stainless steel and some other alloys (e.g.. Inconel, Hastelloy) and they are characterized by a macroporous structure. On the other hand, porous ceramic membranes can be found commercially in various oxides and combination of oxides (e.g., Al203,li02,Zr02, Si02) and pore size families in the mesopore and macropore ranges (e.g., from 1 nm to several microns). Most of the literature studies on three-phase catalytic membrane reactors have been carried out by developing catalytic ceramic membranes. The deposition techniques for the preparation of catalytic ceramic membranes involve methods widely used for the preparation of traditional supported catalysts (Pinna, 1998), and methods specifically developed for the preparation of structured catalysts (Cybulski and Moulijn, 2006). Other methods to introduce a catalytic species on a porous support include the chemical vapour deposition and physical vapour deposition (Daub et al, 2001). The catalyst deposition method has a strong influence on the catalytic membrane reactor performance. 

Figure 3.14 Layout of a laser plasma chemical vapour deposition (CVD) reactor, the gases being introduced to deliver reactants to the substrate surface where plasma was maintained using a CO2 laser.

FTIR measurements were used to monitor the chemical vapour deposition of boron carbide from BCI3/H2/CH4 in an impinging jet reactor. B/C clusters formed in low-temperature matrices (from vapour reactions) were characterised using FTIR spectroscopy, e.g. BxC -x, where x = 0, 1 or 2 n> 5 IR spectra were reported and discussed for B4.3C, B6.5C and BioC. ... 

In chemical vapour deposition, the reaction takes place only on the surface area where the solid product is to be deposited. One way to achieve this is by heating this area (the "susceptor ) to the desired reaction temperature. This is particularly effective when the reaction is endothermic. For exothermic reactions, the opposite wall of the reactor may be cooled. 

Yan et al. (1994) prepared thin Pd membranes using the metal-organic chemical vapour deposition (MOCVD) method in the macropores of an a-alumina support tube. The best Pd membrane was obtained under a pressure of 100-120 Pa inside the reactor and a heating rate of 10°C/min, at 300°C. The H2 permeability was equivalent to that of the membrane prepared by Uemiya et al. (1991d), and the selectivity was higher than 1000 at a permeation temperature of 100-300°C. The H2 permeability was proportional to the first order of the H2 partial pressure, suggesting that the diffusion of dissolved H2 was not rate-determining. H2 embrittlement was restrained at a temperature as low as 100°C, and the membrane was resistant to abrasion in spite of its thinness. 

CVD chemical vapour deposition DFT density functional theory MR membrane reactor PGM porous glass membrane PVD physical vapour deposition SPG Shirasu porous glass TR traditional reactor... 

In chemical vapor deposition (CVD) reactive vapor precursors react to produce solid materials in the gas phase or at the solid-gas interface on the substrate surface at appropriate temperatures. Typical precursors used in the CVD process are metal hydrides, metal chlorides, and metal organic compounds. In the case that the precursor species are metal organic compounds, the process is called metal-organic chemical vapor deposition (MOCVD). The precursor molecules are introduced into a reactor sometimes with a carrier gas and decompose by means of heat, irradiation of UV light, or electrical plasma formed in the gas. Thermal CVD is the most commonly used method. This technique has an advantage that refractory materials can be vapour-deposited at relatively low temperatures,... 

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