The structure stability of short-period InAs/AlSb superlattices (SLs) grown by molecular beam epitaxy was examined by X-ray diffraction, Raman scattering and far-infrared reflectance spectroscopy. The combination of these techniques allowed us to identify modification of the structure properties of InAs/AlSb SLs annealed at various temperatures. Pronounced structure degradation was detected upon short annealing at temperatures as low as 490degreesC. Significant strain relaxation was also observed. These experimental results are understood on the basis of As/Sb exchange during annealing. (C) 2002 Elsevier Science B.V. All rights reserved.