多晶硅还原炉内流场及温度场的研究

Research of Flow Field and Temperature Field in the CVD Reactor

多晶硅还原炉(CVD reactor)是西门子法生产多晶硅的主要设备。硅在多晶硅还原炉(CVD reactor)内的生长是一个复杂的过程,涉及动量、热量、质量传递以及化学反应,炉内流体流动分布是影响还原能耗的关键因素。在这项研究中主要考虑如何提高还原炉中流场和温度场的均匀性。提出了一种新的还原炉设计方案,与传统的多晶硅还原炉相比,在新的还原炉内加入了内罩,从而形成了一种不同的气体流动方式。在新的还原炉内,气体进口和气体出口被划分到不同的区域,气体从气体进口进入CVD reactor后向上流动同时参与气相沉积反应,反应后通过内罩的顶部,最后从气体出口流出。研究重点是内罩结构的设计,以期可以提高还原炉内部流场及温度的均匀性。通过计算流体力学研究,现在水平方向上温度梯度很小,同时有效地减小了回流区域面积。本研究提供了提高多晶硅还原炉内部流场及温度场均匀性的方法。

The Siemens process was extensively applied to the production of polycrystalline silicon. The growth of Si from SiHCl3 in H2by chemical vapor deposition（ CVD） takes place in the CVD reactor,it accompanies with momentum,heat,mass transfer processes and chemical reaction. A good compromise between internal flow field and temperature field uniformity has great influence on the energy consumption of CVD reactor. In this study,a new design of CVD reactor was proposed. A different flow pattern formed due to setting a shield in the reactor. The shield divides the gas inlets and outlets into different zones compared with traditional reactor whose gas inlets and outlets in the same zone. Gases flow upwards after entering the reactor and have chemical vapor deposition reaction,then go across the top of the shield,finally flow out the outlets. Our study focused on the design of shield structure in order to attain good internal flow field and temperature field uniformity. According to the CFD simulation,we found that the gradients of temperature were lower in the horizontal direction,which was contrast to the existing reactor,also the backflow areas were reduced effectively and the temperature in the reactor was lower. This study provides a method for designing CVD reactor so as to improve the uniformity of flow field and temperature field,and accomplish the target of saving energy consumption.