Effect of annealing on microstructure of Co/Cu multilayers

Abstract

The microstructure evolution of magnetron sputtered Co/Cu multilayers induced by annealing has been investigated using X-ray diffraction and reflectometry, atomic force microscopy, and electron microscopy. The experimental results indicated that Co/Cu multilayers with an individual layer thickness of 2 nm showed a stable layer stacking until the annealing temperature reached 600 °C. At that temperature, part of the initial {111} fibre texture transformed into {200} fibre texture. Columnar structure with a multilayer nature was found in the specimen with annealing temperature under 400 °C. All the columnar crystallites originated from the substrate and some of them extended throughout the entire film which led to vertical grain boundary formation. Moreover, the epitaxial growth of Co and Cu sublayer resulted into the mono-crystal-like columnar crystallites with an fcc structure.