Oxidation of TiNi surface with hyperthermal oxygen molecular beams

We report results of our detailed studies on the initial oxidation process of TiNi with a 2 eV hyperthermal oxygen molecular beam (HOMB) and thermal O2 in the backfilling. The oxidation processes are monitored by X-ray photoemission spectroscopy (XPS) measurements in conjunction with synchrotron radiation (SR). In the early stage of oxidation, the precursor mediated dissociative adsorption is the dominant reaction mechanism. In the oxide formation process at higher O coverage, HOMB has the advantage in the dissociation process of O2 molecule and can grow TiO2 layers with the underlying TiOx-rich and/or Ni-rich layers. We succeeded in fabricating thick Ni-free TiO2 layer, possibly blue colored rutile TiO2, combining HOMB and surface annealing.