Growth of large diameter silicon tube by EFG technique:: modeling and experiment

Edge-defined film-fed growth is a widely used technique for growing silicon from its melt in the form of ribbons and hollow cylinders. The current technique of octagonal tube growth is modified to successfully produce 50 cm diameter circular tube. A generic comprehensive numerical model has been developed to simulate a large diameter silicon tube growth process and design the growth system. The magnetic vector potential equation is solved to predict the induced magnetic field in the system and heat generation due to magnetic induction. The high level algorithm MASTRAPP is modified to calculate all modes of heat transfer in the various components of the system. Using this model, a parametric study has been carried out to optimize the system with respect to different controlling parameters like coil configuration, geometry of various components of the system, meniscus height and interface position, global temperature profile, axial temperature profile in the grown tube and power consumption. Several experiments have also been conducted to measure temperature profiles in various sections of the system that agree well with the numerical predictions. Results presented here indicate that the model can be succesfully used to simulate and design an inductively heated silicon tube growth system. Several 50 cm diameter silicon tubes have been succesfully grown.