Interface properties of TiO2 on Si formed by simultaneous implantation and deposition of titanium and oxygen ions

By implanting energetic ions into a substrate, new phases, even far from the thermodynamic equilibrium, can be formed. When combining this method with conventional deposition, more dense films with better adhesion properties due to interface mixing are obtained. The exact nature of the final interface is governed by the energy deposited by the ions as well as the chemical interaction between the affected elements. The aim of this investigation is to elucidate the interface structure at different ion energies by transmission electron microscopy (TEM) for the system titanium dioxide (rutile) on silicon. The films were formed at room temperature by metal plasma immersion ion implantation and deposition (MePIIID) using a cathodic arc in oxygen atmosphere and negative high voltage pulses up to –10 kV with a duty cycle of 9%. Without pulses, a smooth interface between the silicon substrate and columnar and oriented TiO2 is observed, whereas at 10 kV pulse voltage an interface of 18 nm thickness was measured, which corresponds well to the projected range of Ti ions.