This paper focuses on understanding stress development in CuNi42Mnl thin fi
lms during annealing in Ar. In addition to stress-temperature measurements,
resistance-temperature investigations and chemical and microstructural cha
racterization by Auger electron spectroscopy, scanning and transmission ele
ctron microscopy, x-ray diffraction, and atomic force microscopy were also
carried out. The films are polycrystalline with a grain size of 20 nm up to
450 degrees C. To explain the stress evolution above 120 degrees C, atomic
rearrangement (excess-vacancy annihilation, grain-boundary relaxation, and
shrinkage of grain-boundary voids) and oxidation were considered. Grain-bo
undary relaxation was found to be the dominating process up to 250-300 degr
ees C. A sharp transition from compressive to tensile stress between 300 an
d 380 degrees C is explained by the formation of a NiO surface layer due to
reaction with the remaining oxygen in the Ar atmosphere. This oxidation is
masking the inherent structural relaxation above 300 degrees C.