The surface morphology of GaAs layers on (001) InAs substrates, grown by MOVPE at temperatures in the range 500–650 °C and for times from a few seconds to minutes, has been observed by atomic force microscopy. Information on the strain release and on the surface quality has been obtained by Raman scattering and high resolution x‐ray diffraction measurements. Large islands with different shapes and facets are generally formed and only at 550 °C is a quasi‐2D growth observed. At the highest growth temperatures InxGa1−xAs is detected at the interface. ©1996 American Institute of Physics.