Development of mechanical stress in CuNi(Mn) films during temeprature ramping: related mechanisms

摘要

This paper focusses on the development of biaxial stress in Cu_(0.57)Ni_(0.42)Mn_(0.01) thin films during annealing in Ar and, for comparison, in vacuum. Besides stress-temperature measurements also resistance-temperature investigations as well as chemical and microstructural characterization by Auger electron spectroscopy, scanning and transmission electron microscopy, and X-ray diffraction were carried out. To explain the stress evolution, atomic rearrangement (excess-vacancy annihilation, grain-boundary relaxation, and shrinkage of grain-boundary voids) and oxidation were considered. Up to 250 - 300 deg C grain-boundary relaxation was found to be the dominating process. A sharp transition from compressive to tensile stress between 300 deg C and 380 deg C is explained by the formation of a NiO surface layer.