We have studied the mechanism of Be incorporation in InP homoepitaxial films grown by metalorganic molecular beam epitaxy. The actual Be concentration in the films reaches 1–2×1019cm−3while the hole concentration saturates at a lower value &squflg;∼2×1018cm−3in our case). The measured lattice mismatch between film and substrate depends both on growth temperature and Be flux. The resulting changes in morphology suggest that the excess Be forms microclusters in the films grown at higher temperatures—due to the higher surface mobility, leading to the growth of oval defects. Be rejection to the surface is also observed. The surfaces of samples with no cap layer present a granulation which may be related to the formation of a new phase like Be3P2. ©1995 American Institute of Physics.