RESIDUAL-STRESSES INFLUENCE ON THE STRUCTURAL EVOLUTION OF CU-MO SOLID-SOLUTIONS STUDIED BY X-RAY-DIFFRACTION

Metastable Cu-Mo thin films have been deposited on quartz substrates b y ion beam Sputtering. The structural and mechanical state characteris ation in these as-deposited films have been performed using X-ray diff raction. The size of the coherently diffracting domains is small (1.5- 2.0 nm) and the micro-strains are very large (0.3-1.9%). The value of these parameters depends on the Mo concentration. The sin(2) psi metho d was applied to extract stresses and the stress-free lattice paramete r a(0) in the Cu-30 Mo-70 films. In-plane stress is compressive and it s amplitude is very high (4.5 GPa). The presence of such high intrinsi c compressive stresses is related to lattice distortions induced by an 'atomic peening' effect and Ar interstitials during the deposition pr ocess. After thermal annealing, one observes the demixing of the solid solution (a(0) evolution) and an inversion of stress sign (compressiv e to tensile).