Temperature modification of the Nb oxidation at the Nb/Al interface studied by reflEXAFS

We report on the modifications of the Nb oxidation in Nb/Al interfaces due to different thermal treatments. The samples were prepared by radio frequency (RF) ion sputtering and studied by X-ray absorption detected in total reflection mode (reflEXAFS). This technique combines the specific atomic sensitivity property of the extended X-ray absorption fine structure (EXAFS) with a surface sensitivity, due to the total reflection mode of the incident beam. We studied the niobium oxide revealed at the Nb,AL interface after different thermal treatments and on bare thick Nb film. Up to 200 degreesC the increasing temperature does not modify appreciably the oxide layer, while higher temperature treatments (600 degreesC) causes a further oxide formation. The study of the Nb K-edge absorption leads to the conclusion that no single phase Nb oxide is formed at the interfacial zone and no presence of Nb-Al alloy is observed. (C) 2000 Elsevier Science B.V. All rights reserved.