DEFORMATION OF THIN FILMS AND MULTILAYERS

When studying the effects of the scale of the microstructure on mechanical properties experimentally, it is useful to have access to samples in which this scale can be continuously adjusted. Thin films and multilayers are particularly well suited for this purpose. For example, in vapor deposition of face-centered metals with sufficiently high surface mobility compared to the deposition rate (i.e., substrate temperature T ≥ 0.3 Tm; Tm: melting temperature), the grains are columnar (all grain boundaries perpendicular to the film surface), and the average grain size is on the order of the film thickness because grain boundaries are pinned by grooving at that size [1], In multilayers, created by successive deposition of different materials, renucleation of the grains at the start of each layer keeps the grain size on the order of the individual layer thicknesses [2,3].