RESIDUAL-STRESSES IN METALLIC MULTILAYERS

The study of residual stresses in metallic superlattices is of great i mportance. Properties of these materials are a consequence of their ex treme strain states. With respect to single films, both the determinat ion methods and the magnitude of the stresses may:differ in multilayer s. X-ray strain determination must be used with caution because of pos sible interference effects. The large amount of disorder tends to supp ress the modulation on asymmetrical peaks. Stress deduced from wafer b ending experiments may contain a non negligible interfacial contributi on. The very large stresses (greater than or equal to 1Gpa) determined in the superlattices imply very high yield stresses, possibly related to size effects. Anomalous strain free lattice parameters are frequen tly reported. They may be related to the occurrence of segregation dur ing the growth.