We present a nanometric scale analysis of the NiTi/Si, NiTi/SiO2 and NiTi/Si3N4 systems before and after annealing at 500 degreesC during 30 min, by secondary ion mass spectrometry and electron-induced X-ray emission spectroscopy. Before annealing a few nanometers thick transition layer forms at the interface of each system. Under annealing, a NiS2 layer forms in the NiTi/Si system over several tens of nanometers, whereas a TiOx, diffusion barrier builds up at the NiTi/SiO2 interface. A few nanometers thick mix layer composed of TiSi2, TiN and NiSi2, forms at the NiTi/Si3N4 interface. This interface presents an intermediate reactivity under annealing between that of NiTi/Si and NiTi/SiO. (C) 2003 Elsevier B.V. All rights reserved.