Chemical vapor deposition film materials

Polycrystalline thick-film diammid is produced by chemical vapor deposition. These materials are free-standing diamond layers of between 0.2 and 1 nun in thickness and comprise colunmar grains of pure diamond. 

CVD stands for chemical vapor deposition. Raw materials as gases are introduced into the system and the desired substance is formed as a coating on a substrate. Figure 7 shows the schematic figure for a CVD process. Usually the source gas or gases contain elements that would constitute the deposited films. A carrier gas is used in the system and the chemical reaction(s) occurs on the substrate to form a surface coating. 

Zhang, H., Xu, Z. (2002). Microstructure of nanocrystalline SiC films deposited by modified plasma-enhanced chemical vapor deposition. Optical Materials, 20,177-181. 

Reich, S., Hnrald, S., Klhra, H., Laszlri, S. (1992). Deposition of thin films of zirconium and hafnium boride by plasma enhanced chemical vapor deposition. Advanced Materials, 4(10), 650-653. doi 10.1002/adma. 19920041005. 

Carbon Composites. In this class of materials, carbon or graphite fibers are embedded in a carbon or graphite matrix. The matrix can be formed by two methods chemical vapor deposition (CVD) and coking. In the case of chemical vapor deposition (see Film deposition techniques) a hydrocarbon gas is introduced into a reaction chamber in which carbon formed from the decomposition of the gas condenses on the surface of carbon fibers. An alternative method is to mold a carbon fiber—resin mixture into shape and coke the resin precursor at high temperatures and then foUow with CVD. In both methods the process has to be repeated until a desired density is obtained. 

Dimethylcadmium has found use as a volatile source of Cd for metal organic chemical vapor deposition (MOCVD) production of cadmium-containing semiconductor thin films (qv) such as CdS, Cdi 2 Hg -Te, or Cdi 2 Mn -Te, as multiple quantum weU species (32). Semiconductor-grade material seUs for... 

Alternative Thin-Film Fabrication Approaches. Thin films of electronic ceramic materials have also been prepared by sputtering, electron beam evaporation, laser ablation, chemical beam deposition, and chemical vapor deposition (CVD). In the sputtering process, targets may be metal... 

If the rf source is applied to the analysis of conducting bulk samples its figures of merit are very similar to those of the dc source [4.208]. This is also shown by comparative depth-profile analyses of commercial coatings an steel [4.209, 4.210]. The capability of the rf source is, however, unsurpassed in the analysis of poorly or nonconducting materials, e.g. anodic alumina films [4.211], chemical vapor deposition (CVD)-coated tool steels [4.212], composite materials such as ceramic coated steel [4.213], coated glass surfaces [4.214], and polymer coatings [4.209, 4.215, 4.216]. These coatings are used for automotive body parts and consist of a number of distinct polymer layers on a metallic substrate. The total thickness of the paint layers is typically more than 100 pm. An example of a quantitative depth profile on prepainted metal-coated steel is shown as in Fig. 4.39. 

CHEMISTRY OF SUPERCONDUCTOR MATERIALS edited by Terrell A. Vanderah CONTACTS TO SEMICONDUCTORS edited by Leonard J. Brillson DIAMOND CHEMICAL VAPOR DEPOSITION by Huimin Liu and David S. Dandy DIAMOND FILMS AND COATINGS edited by Robert F. Davis... 

Gordon, R. G, Proscia, J., Ellis, F., and Delahoy, A., Texture Tin Oxide Films Produced by Atmospheric Pressure Chemical Vapor Deposition from Tetramethyltin and Their Usefulness in Producing Light Trapping in Thin Film Amorphous Silicon Solar Cells, >/or Energy Materials, (18) 263-281 (1989)... 

Carver, G. E., and Seraphin, B., Chemical Vapor Deposition Molybdenum Thin Films for High-Power Laser Mirrors, mLaser Induced Damage in Optical Materials, Publ. of National Bureau of Standards (Oct 1979)... 

Chemical vapor deposition (CVD) of carbon from propane is the main reaction in the fabrication of the C/C composites [1,2] and the C-SiC functionally graded material [3,4,5]. The carbon deposition rate from propane is high compared with those from other aliphatic hydrocarbons [4]. Propane is rapidly decomposed in the gas phase and various hydrocarbons are formed independently of the film growth in the CVD reactor. The propane concentration distribution is determined by the gas-phase kinetics. The gas-phase reaction model, in addition to the film growth reaction model, is required for the numerical simulation of the CVD reactor for designing and controlling purposes. Therefore, a compact gas-phase reaction model is preferred. The authors proposed the procedure to reduce an elementary reaction model consisting of hundreds of reactions to a compact model objectively [6]. In this study, the procedure is applied to propane pyrolysis for carbon CVD and a compact gas-phase reaction model is built by the proposed procedure and the kinetic parameters are determined from the experimental results. 

Metal and polysilicon films are formed by a chemical-vapor deposition process using organometallic gases that react at the surface of the IC structure. Various metal silicide films may also be deposited in this manner by reaction with the surface of the silicon wafer to form metal silicides. Glass and pol3uner films are deposited or spin cast or both, as are photoresist films (those of a photosensitive material). This process is accomplished by applying a liquid polymer onto a rapidly rotating wafer. The exact method used varies from manufacturer to manufacturer and usually remains proprietary. 

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. 

Uchida, H., Saito, N., Sato, M., Take, M. and Ogi, K. (1994) (Mitsubishi Material Corp) Manufacture of gold thin film by chemical vapor deposition, Jpn. Kokai Tokkyo Koho JP 06,101,046. 

Plasma CVD Plasma chemical vapor deposition. Technique for synthesizing materials in which chemical components in vapor phase excited by plasma react to form a solid film at some surface. 

In chemical vapor deposition (CVD or MOCVD), a film of the desired material is prepared by evaporation of volatile precursor molecules which then decompose to give a film deposited on the substrate. The ordering in the film as it grows is dictated by the surface ordering of the substrate, hence the deposition is epitaxial . The necessary decomposition of the precursor molecules can take place either on the surface of the substrate or in the gas phase close to it. 

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