HEAT-TRANSFER AND THERMAL-DIFFUSION PHENO MENA IN A HORIZONTAL COLD-WALL CVD REACTOR

Heat transfer, fluid flow and thermal diffusion phenomena in a horizon tal cold-wall CVD reactor were investigated theoretically and experime ntally. The flow visualization experiments revealed that a stable two dimensional flow pattern prevails in the He system over a wide range o f Reynolds numbers, while the Na system has a tendency : to form a com plex three dimensional flow structure in which transversal and longitu dinal rolls were included. The calculated results of a two dimensional numerical model accurated represent the experimentally observed flow for the He system. Thermal diffusion phenomena in a cold-wall CVD reac tor were elucidated successively by measuring the composition of SF6 a s a simulated CVD source material. Through experiments, it was found t hat a compositional separation about 3 times larger was likely to be a chieved in the He system, which has a larger value of ratio in molecul ar weight compared to the Nz system. Numerical results calculated usin g a thermal diffusion factor estimated from inlet gas composition agre ed well with experimental results. Fluid how and concentration profile s were changed dramatically under the various gravitational accelerati ons conditions.