InAs/GaAs superlattices with thin (0.5–1 monolayer) δ-InAs insertions were grown by molecular beam epitaxy at low (150–200°C) temperature. The as-grown samples contained up to 1020 cm−3 arsenic antisite defects. Transmission electron microscopic study revealed no extended defect and showed that the real thickness of δ-InAs insertions is 3–4 monolayers. This thickness seems to be due to short-range roughness of the growth surface. Low diffuse scattering and extended interference picture were observed for such superlattices by x-ray diffraction study. Superlattices of two-dimensional cluster sheets were produced by annealing of the δ-InAs/GaAs superlattices at 500–600°C. Precipitation of excess arsenic at InAs δ-layers was found to be accompanied by enhanced In-Ga intermixing, roughening the InAs δ-layers, and smoothing the x-ray interference picture. No evidence for any self-ordering in the system of nanoscale As clusters was revealed using x-ray mapping in reciprocal space.