Energy deposition effects of additional ion bombardment on titanium oxides formed by oxygen implantation
A study of the formation mechanism of titanium oxides induced by O + implantation has been made by means of XRD analysis. Three kinds of ion implantations were employed to investigate the rutile formation process: (1) 75 keV O + implantation into Ti at -60°C, (2) 150 keV O + bombardment at room temperature (RT) into 75 keV O + implanted Ti at -60°C and (3) oxygen ion implantation without mass-separation (O + + O +2) into Ti at an acceleration voltage of 80 kV. The induced oxides formed by three kinds of implantations were characterized in terms of R(211/110), the ratio of the rutile(211) intensity to the rutile(110) intensity of XRD patterns. For the process (1), rutile formation was not observed and only TiO was identified from measured XRD patterns. Additional implantation into the TiO layers, that is the process (2), results in the formation of rutile with the ratio R(211/110) of 0.32-0.33. The process (3) also produces rutile with the ratio R(211/110) of 0.37-0.83. Both values are much different from that formed by O + implantation into Ti at RT, 1.73-1.80. This phenomenon is attributed to the effect of energy deposition.