Design And Analysis Of A New CVD Reactor With Heat Pipes

In the polysilicon industry, the silane method has advantages that Siemens doesn't have: silane has a lower deposition temperature, less energy consumption, silane is easily purified, the output polysilicon has a high purity, the silicon content in silane is high(w=87.5%), which makes the consumption of silane is little. It has a bright development prospect. However a major problem the silane method has to face is that when the environment temperature of furnace is over 400?,it's easy to generate silicon powder which can pollute the silicon rods and affect the quality of the rods, making the production can't achieve the requirements of high-purity polysilicon at the electronic level.The paper is mainly to develop a new polysilicon reduction furnace, in order to compensate for the shortcomings of the traditional silane reactor. The new polysilicon reduction furnace is designed and developed on the basis of the conventional polysilicon reduction furnace, it has three improvements:(1).adding heat pipes which surface is highly polished around silicon rods.(2).adding a guide tube at the center outlet.(3).adding interpolation inlet. This article is mainly study the law of flow field and temperature field in the new reduction furnace. The simulation study of new reduction furnace finds that the guide tube plays a role to collect and export the gas on the top furnace, the heat pipes also play a role in giving guidance and restriction to the gas and the combination of heat pipes and interpolation inlet partitions the flow field and temperature field. The flow field and temperature field distribution is uniform, no gas maelstrom and high temperature area formed.Analysis of energy consumption finds that when the pipes' surface temperature increases from 423 K to 623 K the total energy and radiation energy consumption decreased by 2.84% and 3.87% respectively; when the pipes' surface emissivity decreased from 0.2 to 0.02, the silicon rod total energy and radiation energy consumption decreased by 21.75% and 24.42% respectively. This shows that the change of the emissivity affects the energy consumption is larger than the change of the surface temperature.