Ultra-thin titanium nitride film epitaxy with hyperthermal titanium ions

The growth of ultra-thin titanium nitride films by deposition of titanium ions, possessing hyperthermal energies of several ten electron volts, in a nitrogen ambient is investigated. The hyperthermal titanium ions were produced by a pulsed dc vacuum arc metal plasma source. The TiN films were deposited at substrate temperatures in the range from 700°C down to room temperature on MgO(100). The crystalline surface structure of the films was monitored in situ by reflection high energy electron diffraction. The crystallographic structure was investigated by X-ray diffraction. High resolution transmission electron microscopy was used to examine the morphology and defect structure of the films. An ultra-high vacuum scanning-probe microscope was used to investigate the surface topography of the films. The results show that all the ultra-thin TiN films deposited this way are epitaxial, even at room temperature, indicating the beneficial effect of the hyperthermal energy of the particles involved in the deposition process.