The role which microgravity plays for the understanding of the growth of semiconducting materials is reviewed. Main emphasis is placed on the interactiou of fluid flow and mass transport phenomena during different growth processes. the character and strength of surface tension driven flows. the limitations of diffusive transport regimes. and possibilities provided by magnetic fields with respect to Support or replace microgravity conditions. Some of the most relevant topics to be investigated during the next decade on board the International Space Station are outlined. The first results of experiments carried out on the ISS are presented. (C) 2002 Elsevier Science B.V. All rights reserved.