Deformation properties of thin metallic films deposited on hard substrates.

摘要

Thin metallic films attached to rigid substrates exhibit enhanced flow properties when compared to their free-standing counterparts. This difference is a result of the constraint the substrate places on the films deformation behavior through strong film/substrate adhesion along with the substrate acting as a barrier to dislocation motion.; A continuous indentation test has been developed for probing the flow properties of thin metallic films deposited on hard substrates. The load-depth response of submicron thick and micron thick aluminum and copper films under a variety of indenters geometries has been modeled with a modified forging analysis. This model accounts for the influence of interfacial adhesion on thin film flow properties to be separated from the effects of residual stress, film thickness, grain size and microstructure.; The combination of strong interfacial adhesion and a difference in thermal expansion between film and substrate can, upon thermal cycling, result in thermally induced stresses. Depending on the film/substrate system and temperature, these stresses can relax with time.; The evolution of this stress relaxation process in aluminum thin films was investigated with both a continuous indentation test and a sin{dollar}sp2psi{dollar} x-ray stress measurement technique. The stress relaxation behavior observed by both of these techniques was similar indicating that the continuous indentation test could be used to investigate stress relaxation in thin film geometries too small to investigate with other techniques.; An indentation load relaxation technique to investigate directly the influence of the substrate on thin film stress relaxation behavior. The relaxation behavior of the thin film far away from the film/substrate interface was found to be the same as conventional load relaxation behavior of bulk samples of the same material. At depths close to the film/substrate interface, the observed stress relaxation behavior is influenced by the presence of the substrate.