Transport phenomena in a cold wall vertical reactor for metalorganic vapor phase growth of β-SiC layers

The deposition rate and uniformity in CVD reactors are function of transport phenomena. A mathematical model including the coupled mass transfer with hydrodynamics and heat transfer has been developed to predict reactant concentrations, flow patterns and temperature fields in a cold wall CVD reactor. The model consists of the partial differential equations describing the balance of mass, momentum, heat and species concentration and variable gas properties. The equations are solved numerically in two-dimensional, axisymmetric form using a control-volume-based finite difference technique. The model is applied to growth of silicon carbide layers obtained by LPCVD from the pyrolysis of tetramethylsilane. We present computed temperature, velocity and TMS concentration profiles. We compare predicted deposition rates with experimental result

INFLUENCE OF H2 PARTIAL PRESSURE ON THE MORPHOLOGY AND CRYSTALLIZATION OF SiC LAYERS OBTAINED BY LPCVD USING TETRAMETHYLSILANE

Silicon carbide layers have been produced by Chemical Vapor Deposition at low pressures (LPCVD) on graphite substrates from tetramethylsilane and hydrogen. The effects of change in partial pressure of hydrogen on the kinetics, morphology and structure of the layers have been examined. A model of the layer growth is developed

Controlled Nucleation and Growth of Thin Hydroxyapatite Layers on Titanium Implants by Using Induction Heating Technique

5 pages, 6 figures, 2 tables.This paper reports the results obtained by the development of a new wet method of hydroxyapatite (HA) thin layer deposition. The method is based on the localized precipitation of HA on metallic substrates activated by induction heating. The technique developed has been shown to allow for the complete coating of substrates with micrometric thin films of HA within a low processing time. The method has been successfully applied to coat Ti plaques and Ti-6Al-4V cylinders.This work has been carried out in the framework of the Spanish-French LEA-SIMAP Laboratory. The Ministry of Science and Technology of Spain is acknowledged with thanks for financial support of D.N.M. within the program “Ramon y Cajal”.Peer reviewe