Semiconductor Crystal Growth and Segregation Problems on Earth And in Space

ABSTRACTCrystals grown from the melt exhibit compositional and structural defects which limit the exploitation of their full potential in solid state electronics. The origin of these defects is related primarily to gravity-induced convective currents in the melt. In semiconductor compounds additional problems are introduced from variations in stoichiometry. Progress has been made recently in relating qualitatively, and in some instances quantitatively, the growth parameters to the materials properties of the crystals, and in turn to their electronic properties. Overcoming the presence of gravitational forces in space eliminates or minimizes convective interference and, thus, the quantitative assessment of the key growth parameters controlling the chemical and structural perfection of single crystals becomes possible. Results (obtained on earth) will be presented on the growth-property relationships of elemental and compound semiconductors. The advantages, as well as the limitations, that zero gravity conditions present for crystal growth will be discussed.