Two types of multiple quantum wells (MQWs) have been grown by means of molecular beam epitaxy; one is GaInAs/GaAs and the other is GaInNAs/GaNAs. Deteriorated structural qualities were observed in the GaInNAs/GaNAs MQWs with a low N concentration as compared to the N-free MQWs grown at the same conditions; an increase of N content within the QWs avoids the structure deterioration. The evolution of X-ray diffraction patterns, due to post-growth thermal annealing indicates that In/Ga interdiffusions occurred in both types of MQWs at elevated temperatures. The diffusion length deduced from the dynamic simulations shows a decrease with the increase of N concentration. The interfaces roughness plays a minor role in the interdiffusion. The thermal stabilities of GalnNAs/GaNAs MQW structures are improved by the incorporation of N. (c) 2007 Elsevier B.V. All rights reserved.