Development of Magnetic Field Assisted Melt Stabilization with Heat and Mass Transfer Control in Low Pressure LEC Growth of GaAs

摘要

This research effort permits operation on a scale compatible with industry and establishes the basis for advanced science and technology transfer in the area of bulk crystal growth of elemental and compound semiconductors. It led to the development of a computer controlled, model-based magnetic LP-LEC facility for growth of GaAs at diameters in excess of 3 inches. In conjunction, a thermal imaging system was created which permits monitoring and control of the growth process as well as, from video-tape, the post-growth analysis of thermal field distribution and its changes. This capability makes it possible to analyze for correlations between the thermal history of a semiconductor and its properties. The imaging system is also an essential element for monitoring the effectiveness of heat transfer control and the viability of model-based feedforward growth control. The crystal growth research provided the background for major advances in our ability to characterize qualitatively on a micro- and macroscale the free charge carrier distribution (dopant distribution) in semiconductors. The opto-analytical approach taken provides for quantitative analyses of unprecedented spatial resolution and sensitivity within seconds and thus appears ideally suited for transfer to technology. Liquid encapsulated czochralski growth. (jhd)