| Summary: | 碩士 === 國立聯合大學 === 材料科學工程學系碩士班 === 104 === SiC, with low thermal expansion, high thermal conductivity and hardness, well chemical resistance and high temperature oxidation resistance, has been used for the substrate protection under high temperature such as LED epitaxy, graphite heat sink, carbonic mold, etc. In generally, SiC film has been produced by chemical vapor deposition (CVD). The deposition rate of SiC film is strongly affected by temperature, pressure, gas flow rate, and intermediates adsorption on the substrate surface. The coating uniformity is relative to the difference of deposition rate each site on substrate.
In order to achieve the better double-side deposition rate and uniformity, the numerical simulation model based on thermal flux was constructed by Fluent software in this study. The transport equations for fluid dynamics, heat transfer and mass transfer are simultaneously solved by employing the finite element method. The effects of process parameters and substrate arrangements on deposition were studied.
From the simulation results, increasing reactor heating temperature could get not only the excellent deposition rate but also the great uniformity of SiC film. The higher operating pressure would obtain the rapid deposition rate, but the uniformity became worse. The larger species flow rate diminished the deposition rate, and the uniformity shown the opposite tendency on double-side of substrate. However, the film uniformity of entire substrate still increased with the gas flow rate. Although increasing the incline angle of substrate could not achieve the same tendency of deposition rate each single-side on substrate, the uniformity of deposition could be increased on whole substrate. Even though the deposition rate and uniformity might be reduced by adding substrate numbers, the higher productivity and low cost should be obtained in multi-substrate design and could benefit industrial work. From the above, the best deposition rate and uniformity could achieve where the reactor heating temperature is 1800 K, the operating pressure is 10 kPa, the SiCl4, CH4 and H2 flow rate are 1.2, 1.2 and 10 slm and the reactor arrangement is vertical single substrate design.
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