The Cu/Cr/Si structure was studied for thermal stability using thin Cr layers as a barrier in the range of 10 to 40 nm, between 250 and 500 degrees C for 30 min. Investigations using sheet resistance method, deep level transient spectroscopy (DLTS), X-ray diffraction (XRD) analysis, Rutherford backscattering spectroscopy (RBS), and adhesion tests were carried out, to reveal the behavior of Cu and Cr in the Cu/Cr/Si structures. It is shown that even a IO-nm thin Cr layer preserves the multilayer structure up to 400 degrees C and that Cu silicide formation is observed only after annealing at 450 degrees C. However, as found by DLTS, compared with the conventional characterization techniques, Cu migration into the structure reduces the effectiveness of the Cr layers as a diffusion barrier at 50 degrees C.