Chemical vapor deposition thermal process

As was shown by Berdinsky et al. [4], due to CNTs deep rooting within the ion tracks, the CNTs should be more stable than others against a mechanical influence. Moreover, any chemical vapour deposition (CVD) process allows to get bended CNTs, which are interlaced that leads to an increase of mechanical stability of the CNTs array. This could prevent decomposition of CNTs during the field emission process. Therefore, the conventional thermal chemical vapor deposition (TCVD) process can give the array of CNTs and randomize location of their tips with different height. 

The growth rate of thermal oxidation decreases with increase in the thickness of oxide layer, because it relies on the diffusion of oxygen. The chemical vapor deposition (CVD) process can make thicker silicon dioxide layer and does not require silicon substrate. Silane is a toxic extremely flammable chemical compound with chemical formula SiH4. The silane CVD process using silane gas is based on the following reaction ... 

In a plasma-enhanced chemical vapor deposition (PECVD) process, a substrate is exposed to one or more volatile precursors whose atoms or molecules react and/or decompose on the substrate surface, typically using hydrogen in a thermal activation to produce the required deposition. Compounds, such as oxides and nitrides, are produced in reaction with the plasma gas species, usually at lower temperature. A plasma polymerization can occur on a surface when a precursor vapor is not completely decomposed within the plasma. 

Jensen K F and Kern W 1991 Thermal chemical vapor deposition Thin Film Processes II ed J L Vossen and W Kern (San Diego, CA Academic) chapter III-1, pp 283-368... 

Chemical vapor deposition competes directly with other coating processes which, in many cases, are more suitable for the application under consideration. These competing processes comprise the physical vapor deposition (PVD) processes of evaporation, sputtering, and ion plating, as well as the molten-material process of thermal spray and the liquid-phase process of solgel. A short description of each process follows. For greater detail, the listed references should be consulted. 

The most intensive development of the nanoparticle area concerns the synthesis of metal particles for applications in physics or in micro/nano-electronics generally. Besides the use of physical techniques such as atom evaporation, synthetic techniques based on salt reduction or compound precipitation (oxides, sulfides, selenides, etc.) have been developed, and associated, in general, to a kinetic control of the reaction using high temperatures, slow addition of reactants, or use of micelles as nanoreactors [15-20]. Organometallic compounds have also previously been used as material precursors in high temperature decomposition processes, for example in chemical vapor deposition [21]. Metal carbonyls have been widely used as precursors of metals either in the gas phase (OMCVD for the deposition of films or nanoparticles) or in solution for the synthesis after thermal treatment [22], UV irradiation or sonolysis [23,24] of fine powders or metal nanoparticles. 

For illustrative purposes, the process of deposition of Si onto graphite is being used as an example. The 15 pm natural graphite precursors were introduced into the industrial size chemical vapor deposition reactor, where a thermal decomposition of silane (SiH4) into the silicon and hydrogen was taking place under inert gas in accordance with the equation (1) ... 

Chemical vapor deposition (CVD) is a process whereby a thin solid film is synthesized from the gaseous phase by a chemical reaction. It is this reactive process that distinguishes CVD from physical deposition processes, such as evaporation, sputtering, and sublimation.8 This process is well known and is used to generate inorganic thin films of high purity and quality as well as form polyimides by a step-polymerization process.9-11 Vapor deposition polymerization (VDP) is the method in which the chemical reaction in question is the polymerization of a reactive species generated in the gas phase by thermal (or radiative) activation. 

Chemical vapor deposition (CVD) involves the reaction of gaseous reactants to form solid products. There are two general types of CVD processes (a) the thermal decomposition of a homogeneous gas to form a solid and (b) the chemical reaction of two or more gaseous species to form a solid. Both types of CVD reactions are used industrially to form a variety of important elements and compounds for semiconductor, superconductor, and ceramic coating applications. 

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