In situ observation experiments of semiconductor solution growth using a near-infrared microscope have been performed to investigate an influence of surface orientation of a substrate crystal upon the morphological change of the S/L interface. The orientation dependence of step kinetic coefficient at the interface in GaP/GaP growth was obtained under a reduced convection condition in order to evaluate a behavior of macrosteps during the growth. A morphological change of S/L interface at the early stage of GaAsxPl-x/GaP hetero-LPE growth was also discussed from the view point of the surface orientation dependence. (c) 2004 Elsevier B.V. All rights reserved.