In order to optimize the molecular beam epitaxy growth of indium arsenide-gallium antimonide structures, we study the effects of the stacking sequence of the interfacial monolayer and of the growth temperature. To this end, GaSb/InAs and InAs/GaSb heterojunctions involving ultra-thin epilayers have been fabricated at 350 degrees C, 400 degrees C and 450 degrees C with In-Sb- or Ga-As-like interfaces. The structures have been investigated by reflection high-energy electron diffraction, Anger electron microscopy and atomic force microscopy. The best growth condition for InAs(100) as well as GaSb(100) have been obtained with a substrate temperature of 400 degrees C and an In-Sb-like InAs-GaSb interface.