Diffusion barrier performance of thin Cr films in the Cu/Cr/Si structure

We have studied the thermal stability of thin (from 10 to 40nm) sputter dep osited Cr layers as a diffusion barrier in Cu/Cr/Si structure. Sheet resist ance measurements, DLTS, X-Ray Diffraction analysis (XRD), Rutherford Backs cattering Spectroscopy (RBS), Auger Electron Spectroscopy (AES) and adhesio n tests were carried out in order to reveal the behaviour of Cu and Cr in t he Cu/Cr/Si structures. It is shown that even the 10 nm thin Cr layer prese rves the multilayer structure up to 400 degrees C, and Cu silicide formatio n is observed only after annealing. at 450 degrees C for 30 min. DLTS measu rements revealed the Cu migration into the structure at lower temperatures (in this case at 350 degrees C) than the other characterization techniques.