Generic numerical modeling for semiconductor and optical crystal growth with and without faceting in vertical Bridgman system

Bridgman crystal growth system is widely utilized to the growth of single crystals. The advantages of the Bridgman system mainly come from the combination of easy construction of equipments and precise control of temperature gradient. The increased demand for semiconductor and optical crystals of high quality at low cost has motivated extensive research efforts on crystal growth simulations. However, systematic Bridgman crystal growth simulation is not well presented in open literature, and some complexities of the phenomena involved are often neglected or highly simplified, e.g., transient interface movement responding to the thermal environment fluctuation, faceting phenomenon at the solid-liquid interface, and radiation heat transfer during crystal growth process. This dissertation is aimed at developing a fundamental understanding of the transport phenomena during the vertical Bridgman crystal growth process, and investigating the process conditions and optimization. For this purpose, a comprehensive numerical model is developed for the crystal growth in a vertical Bridgman furnace, which includes a transient solid-liquid interface-tracking scheme using the Multiphase Multi-Grid Generation method (MAGG). Special attentions are directed to semiconductor crystal growth under constant and alternating electric field, faceting phenomenon at the solid-liquid interface and radiation heat transfer simulation for optical crystal growth.; Faceting at the solid-liquid interface is a common phenomenon in growing semiconductor and optical crystals. In the second part of the thesis, computational simulation of faceting is carried out, using YAG crystals as an example. The numerical scheme considers the coupling between a kinetic undercooling model with the melt convection and thermal transport calculations. The interface location is tracked, which records an initial time-dependent evolution of the facet towards its time-independent shape. The effects of crystal growth surroundings on the facet sizes are also investigated. (Abstract shortened by UMI.)...