Influence of ion energy on titanium oxide formation by vacuum arc deposition and implantation

Titanium oxide thin films were produced by vacuum are deposition while puls e biasing the substrate. The stoichiometry can be influenced by varying the oxygen partial pressure and the are current from semiconducting and transp arent TiO1.8, to metallic TiOx (x approximate to 1.4). Without additional b ias voltage, a hyperthermal energy of 25-50 eV of the titanium and oxygen i ons leads to the growth of columnar textured rutile films on silicon, with their orientation solely determined by the substrate orientation. While app lying negative high voltage pulses between 1 and 5 kV with a duty cycle of 9% no loss of this texture was observed. This can be explained by the rathe r high displacement energy of 50 eV for rutile. Using atomic force microsco py (AFM) an increasing surface roughness, caused by a larger sputter etchin g of the grain boundaries, as well as an increase in the column diameter wa s observed. At 10 kV pulses a broadening and splitting of the rutile (1 10) peak in X-ray diffraction (XRD) was observed, indicating enough mobility o f oxygen vacancies and titanium interstitials to start the formation of the Magneli phases TinO2n-1. (C) 2001 Elsevier Science B.V. All rights reserve d.