Ion beam mixing of Ti/Al interfaces by nitrogen irradiation

Titanium/aluminium interfaces produced by titanium thin film deposition on aluminium substrates have been reactively mixed using N 2 + ion beams of 2 and 3 keV at room temperature (RT). The ion beam mixing (IBM) has been analysed using X-ray photoelectron spectroscopy (XPS) and Monte Carlo TRIDYN simulations. Below ∼3 × 1016 ions/cm2, the IBM kinetic is characterized by a strong decrease of the Ti concentration along with a fast nitrogen incorporation up to ∼50%. Above that ion dose, the Ti/Al ratio can be varied in a broad range, whereas the nitrogen concentration slightly decreases with increasing the aluminium content of the film. The comparison of experimental results with those obtained from TRIDYN, that uses pure ballistic mechanisms, suggests that processes driven by residual defects are the rate-controlling mechanisms during the reactive IBM of Ti/Al interfaces.