Characterization of heating and nitriding processes of titanium thin films grown on NaCl(001) substrate held at room temperature

Kasukabe, Yoshitaka*; Watanabe, Yohei*; Yamamoto, Shunya; Yoshikawa, Masahito; Fujino, Yutaka*

Titanium nitrides (TiN) are non-stoichiometric compounds and show covalent properties as well as metallic and ionic properties, which make them fascinating for both fundamental research and technological applications. The purpose of this work is to study changes of the crystallographic and electronic structures of Ti films by heating and by nitriding during N-implantation into Ti films separated from NaCl(001) substrates, using in-situ transmission electron microscope (TEM) equipped with the instrument for electron energy loss spectroscopy (EELS), and then to clarify the atomistic nitriding processes of Ti thin films due to the N-implantation with the aid of molecular orbital calculations. The present calculations throw light on the hcp-fcc transformation mechanism between fcc-Ti sublattices and hcp sublattices due to the release of H atoms or due to the implantation of N atoms, taking into account the bonding interaction of Ti sublattices with ligand H or N atoms.