In this work we studied the As redistribution in SiO2(70 nm)/Si(30 nm)/SiO2(70 nm) multilayer during postimplantation annealing. By Rutherford backscattering spectrometry and Z-contrast transmission electron microscopy we found an As accumulation at the Si/SiO2 interfaces and at the Si grain boundaries with no segregation of the As in the Si layer. Such an effect could be qualitatively in agreement with a model that assumes a traps distribution into the Si in the first 2–3 nm above the SiO2/Si interfaces and along the Si grain boundaries. In particular, the traps concentration at the Si/SiO2 interfaces was estimated in 1014 traps/cm2.