Optimum Convection Conditions for Czochralski Growth of Semiconductors

摘要

Time dependence of flow patterns in conventional Czochralski pulling of semiconductor crystals like silicon and gallium arsenide leads to corresponding temperature fluctuations at the growth interface. In order to minimize the resulting inhomogeneities (striations) the general approach is to reduce convection by either applying damping magnetic fields or by growth in microgravity. An alternate approach is the application of enforced convection which leads to homogenization of the whole melt and to the well-defined conditions at the growth interface. The advantages and disadvantages of the various approaches are discussed.