Integrated Intelligent Modeling, Design and Control of Crystal Growth Processes.

摘要

Growth of single crystals is the critical beginning step for electronic, opto-electronic, MEMS and many other devices. This MURI program took an integrated approach towards modeling, design and control of crystal growth processes and in conjunction with growth and characterization experiments developed much better understanding of growth phenomena and materials defects. It led to the development of most comprehensive and accurate models that account for conduction, convection and volumetric, spectral radiation heat transfer, oscillatory and turbulent flows, transport and segregation of dopants and impurities, phase change, an applied magnetic and/or electric field, and generation and multiplication of crystal defects. Using state-of-the-art adaptive grid generation techniques and parallel algorithms, the models can perform three-dimensional, dynamic simulations. While establishing white beam x- ray topography as the leading technique for crystal characterization, this research led to many new theories for grow the behavior and defects. Advanced model-based control algorithms were developed for in-situ synthesis and Czochralski growth. Notable among many successful technology transfer projects are: AFRL-developed one-step in-situ synthesis and growth of indium phosphide crystals, growth of large diameter silicon carbide crystals, 500 mm diameter silicon tube growth, transport model for hydrothermal growth, wire saw technology and high yield polysilicon production. Besides involving numerous faculty, the project succeeded in training a large number of postdoctoral fellows and undergraduate and graduate students in crystal growth.