硅外延生长高频感应系统的热场仿真

应用多物理场分析工具COMSOL Multiphysics软件中的磁场和固体传热两种模块,建立了平板式外延炉反应腔体的有限元模型.结合高频感应加热的机理,分析了电磁场与热场耦合作用,重点研究了感应加热系统中线圈结构、电流密度和频率对热场分布的影响.模拟结果表明,高频感应系统呈现出明显的趋肤效应,感应电流主要集中在基座下表层,焦耳效应主要发生在涡流区,基座上部的热量来源于热传导.实验中,通过调节感应线圈横向和纵向的位置,改变了磁通密度的分布,从而决定了腔体内的热场分布.根据模拟仿真结构,对外延工艺的温度分布进行优化,实现了热场的径向温度梯度变化小于10℃,在此条件下,硅外延片电阻率的标准偏差为0.56％.

Thermal Field Simulation of the High-Frequency Induction System in the Si Epitaxial Growth

The finite element model for the plate epitaxial furnace reaction chamber was established by using the magnetic field and solid heat transfer modules in the multi-physics field analysis tool of COMSOL Multiphysics software.With the mechanism of high-frequency induction heating,the coupling between the electromagnetic field and the thermal field was analyzed.The influence of coil structure,current density and frequency on the thermal field distribution in the induction heating system was emphatically studied.The simulation results show that the high-frequency induction system exhibits obvious skin effect.The induced current is mainly concentrated on the bottom surface of the susceptor,and the Joule effect mainly occurs in the eddy current region.The heat in the upper part of the susceptor is derived from heat transfer.In the experiment,the distribution of the magnetic flux density was changed by the variation of the transverse and longitudinal positions of the induction coils,thus determining the thermal field distribution in the cavity.According to the simulation structure,the radial temperature gradient change of the thermal field is less than 10 ℃ by optimizing the temperature distribution of the epitaxial process.And the standard deviation of resistivity of the silicon epitaxial wafer is 0.56％ under this condition.