Anomaly in Sputtering on Titanium Nitride Film Growth by Post-Irradiation Processing*1

We have developed an ultrahigh-vacuum (UHV) apparatus which enables reflection high-energy electron diffraction (RHEED), sputtering yield measurement and ion scattering spectroscopy (ISS) to be performed simultaneously, leading to a more comprehensive understanding of the growth mechanism of titanium nitride (TiN) film by post-irradiation processing. The sputtering yield measurement revealed an anomalous sputtering phenomenon in the initial stage of post-irradiation processing, i.e., sputtering hardly took place on a titanium film under 3 keV N2 + ion irradiation for doses below ∼5×1015 ions/cm2. Further N2 + ion irradiation led to a low sputtering yield for doses between ∼5×1015 ions/cm2 to ∼3×1016 ions/cm2, and finally approached a steady-state sputtering for doses above ∼3×1016 ions/cm2. Monitoring of the surface composition was also performed by ISS to examine whether the surface composition follows the change of the sputtering behavior or not.