PRESENT STATUS OF RESEARCH ON CHEMICAL VAPOR-DEPOSITION METHODS AND SIGNIFICANCE OF CHEMICAL-ENGINEERING APPROACH

Chemical vapor deposition (CVD) methods to prepare solids from gaseous species through chemical reactions is potentially one of the most fundamental technologies in material maunfacturing. The key issues in CVD processes include material, form, rate, and condition. This review discusses the present status of research on CVD, focusing on control of form and rate and the significance of the chemical engineering approach in this field. Form is defined to include shape, scale, and uniformity of the material prepared. First, a factor to control the form is the profiles of concentrations and temperature., T nese profiles influence directly the uniformity in the preparation rate in a CVD reactor, while the integral of the profiles governs the effluent stream in petrochemical reactors. Second, how to scale up microscopic-scale the preparation of a substance to material scale provides a bottle-neck in material manufacture technology. The most fundamental control a CVD methods is selective production of a film on a substrate or particles in the gas phase. A dimensionless group is proposed as a measure of the tendency to produce particles in the gas phase. To interpret systematically a large volume of data in the field of CVD, modeling of phenomena by the chemical engineering approach is indispensable. © 1990, The Society of Chemical Engineers, Japan. All rights reserved.