The CVD of Ceramic Materials Oxides

The number of oxides is large since most metallic elements form stable compounds with oxygen, either as single or mixed oxides. However, the CVD of many of these materials has yet to be investigated and generally this area of CVD has lagged behind the CVD of other ceramic materials, such as metals, carbides, or nitrides. The CVD of oxides has been slower to develop than other thin-film processes, particularly in optical applications where evaporation. 

Only those oxides for which CVD information has been reported in the literature and which are of some industrial importance are reviewed here. In this chapter, each of these oxides is listed alphabetically with its basic properties, its maj or CVD reactions and processes, and its present and potential applications. A more extensive review of applications is given in Chs. 13 to 19. 

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Gordon,R. G., Recent Advances in the CVD of Metal Nitrides and Oxides, Proc. of the Conf on MOCVD of Electronic Ceramics, Material Research Soc., Pittsburgh, PA (1994)... 

Another possibility of ceramic material application is the use of coatings and foams inside, for example, metallic microstructure devices. Here, well-known technologies such as CVD processes, sputtering, electrophoretic deposition, sol-gel methods in combination with spin coating, dip coating, or wash coating methods, or the use of anodic oxidation for aluminum-based devices will lead to either dense, protective ceramic coatings or porous layers used as catalyst support. 

Ceramic and semiconductor thin films have been prepared by a number of methods including chemical vapor deposition (CVD), spray-coating, and sol-gel techniques. In the present work, the sol-gel method was chosen to prepare uniform, thin films of titanium oxides on palladium Titanium oxide was chosen because of its versatility as a support material and also because the sol-gel synthesis of titania films has been clearly described by Takahashi and co-workers (22). The procedure utilized herein follows the work of Takahashi, but is modified to take advantage of the hydrogen permeability of the palladium substrate. Our objective was to develop a reliable procedure for the fabrication of thin titania films on palladium, and then to evaluate the performance of the resulting metalloceramic membranes for hydrogen transport and ethylene hydrogenation for comparison to the pure palladium membrane results. 

Numerous ceramics are deposited via chemical vapor deposition. Oxide, carbide, nitride, and boride films can all be produced from gas phase precursors. This section gives details on the production-scale reactions for materials that are widely produced. In addition, a survey of the latest research including novel precursors and chemical reactions is provided. The discussion begins with the mature technologies of silicon dioxide, aluminum oxide, and silicon nitride CVD. Then the focus turns to the deposition of thin films having characteristics that are attractive for future applications in microelectronics, micromachinery, and hard coatings for tools and parts. These materials include aluminum nitride, boron nitride, titanium nitride, titanium dioxide, silicon carbide, and mixed-metal oxides such as those of the perovskite structure and those used as high To superconductors. 

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