Mechanical behavior of Cu/TiN multilayers at ambient and elevated temperatures: Stress-assisted diffusion of Cu

Raghavan, R.; Wheeler, J. M.; Esqué-de los Ojos, D.; Thomas, K.; Almandoz, E.; Fuentes, G. G.; Michler, J.

Materials Science and Engineering A 620 (2015)

The deformation and failure mechanism of a multilayered thin film consisting of alternating soft Cu and hard TiN interlayers has been studied by in situ SEM compression of micro-pillars and finite element simulations. While the yielding of the multilayer is governed by the ‘size-dependent’ strength of Cu, the failure was found to occur by shearing of the columnar grains of TiN. At elevated temperatures of 200 and 400. °C, the yielding of the multilayers is governed by the stress-assisted diffusion of the Cu interlayers, which coalesce into microcrystals and grow into larger faceted crystals.