THE SYNTHETIC PRODUCTION OF LARGE SINGLE CRYSTALS

THE SYNTHETIC PRODUCTION OF LARGE SINGLE CRYSTALS HAS RECENTLY BECOME A PROBLEM OF CRITICAL IMPORTANCE TO THE ELECTRONICS INDUSTRY. THE DEVELOPMENT OF FASTER AND MORE POWERFUL MICROCOMPUTER CHIPS DEPENDS ON THE AVAILABILITY OF UNIFORM CRYSTALS OF MORE EXOTIC MATERIALS THAN THE TRADITIONAL SILICON. RECENT EXPERIMENTS IN THE SPACE SHUTTLE HAVE DEMONSTRATED THE SIGNIFICANT POTENTIAL FOR THE PRODUCTION OF SUCH CRYSTALS IN A MICROGRAVITY ENVIRONMENT. HOWEVER, WHILE THERMAL CONVECTION EFFECTS ARE SIGNIFICANTLY REDUCED IN SPACE, THERMOCAPILLARY CONVECTION BECOMES EXTREMELY IMPORTANT, AND IT IS CRITICAL TO DEVELOP A PREDICTIVE CAPABILITY FOR THE PHYSICS OF CRYSTAL MELT FLOWS IN SUCH AN ENVIORNMENT. THIS PROBLEM IS MAGNIFIED BY THE LACK OF ANY TERRESTRIAL FACILITIES FOR PERFORMING EXTENDED LABORATORY EXPERIMENTS UNDER MICROGRAVITY CONDITIONS. THE OBJECT OF THIS PROPOSAL IS THE DEVELOPMENT AND IMPLEMENTATION OF HIGH ACCURACY NUMERICAL CODES FOR PREDICTING THE EVOLUTION OF CRYSTAL MELT FLOWS IN SPACE AND PERFORMING SIMULATIONS WITH THESE CODES TO HELP IN THE DESIGN OF SPACE LABORATORY EXPERIMENTS.