ABSTRACT John S. Walker Univ. of ILL. Urbana-Champaign CTS-9419484 Computer circuits and optical devices are produced on wafers sliced from crystals of semiconductors such as silicon, gallium-arsenide and indium-phosphide. Advances in computers and in optical devices have produced a demand for better crystals. A crystal is grown from a volume of liquid, and its properties are determined by the motion of the liquid during crystal growth. A magnetic field can be used to control the liquid motion and thus produce crystals with better properties. Mathematical and numerical methods are used to predict how a specific magnetic field will affect the liquid motion and the properties of the crystal. With the models begin developed, the magnetic field can be optimized in order to achieve the greatest possible improvement in the properties of the crystals. Improved crystals will lead to faster and more reliable computer circuits and to superior optical devices, such as lasers and high-speed optical communication systems.
