Nanoscale chemical and structural reconstruction in thermally oxidized TiN/SnO2 ultrathin films

Abstract

The chemical and nanostructural changes of TiN/SnO2 composite films during post-deposition annealing (PDA) was investigated by scanning electron microscopy, transmission electron microscopy, and X-ray absorption spectroscopy. It was found that during annealing in an oxygen-rich environment, TiN is converted to TiO2 and diffuses into the SnO2 region along grain boundaries to form a SnO2/TiO2 oxide nanocomposite. In addition, rupture of the Si substrate in contact with the nanocomposite was clearly observed. The nanostructural changes and rupture of the Si surface were found to depend on the oxygen partial pressure during PDA, indicating that thermal oxidation can induce abrupt chemical and structural reconstruction in the composite films. (C) 2020 Elsevier B.V. All rights reserved.