<Abstrate>

Residual stresses and stress gradients are of great importance in

all thin film systems, as they critically influence the structural

stability and functionality, and thus the lifetime, of the concerned

devices. In this study, an improved ion beam layer removal method

is developed to determine the stress distribution in copper- and

tungsten-based thin film systems. Cantilevers were prepared from

single, bi- and tri-layer systems with an individual layer thickness of

500 nm using focused ion beam machining. Subsequently, residual

stress profiles were determined with a depth resolution of 50 nm,

employing the ion beam layer removal method. We observe that the

evaluated average film stresses correspond to state-of-the-art X-ray

diffraction measurements. However, depending on the layer order,

different stress profiles with strong stress gradients evolve, and

pronounced changes in residual stress occur across an interface within

only few grains. These novel findings have profound implications

when addressing the interface adhesion, fracture properties and

reliability of novel thin film systems, as well as interface dominated

materials in general.

<全文連結>