Structural characterization of mixed Ta-Re oxide films

Thin films of mixed Ta and Re oxides have been produced by reactive dc magnetron co-sputtering of pure Ta and Re metal targets in Ar-O₂ atmosphere. The structural evolution of these films has been studied as a function of the composition, starting from a pure tantalum oxide film up to about 82% rhenium content. The composition and the structure of the films have been investigated by using X-ray diffraction and micro-Raman spectroscopy. For low Re content (20%), islands of a well crystallized phase, based on ReO₄ groups, appear in the films still composed by pure amorphous tantalum oxide, while a mixed disordered solid phase is found for the highest Re concentration (82%).