Enhanced ion irradiation tolerance properties in TiN/MgO nanolayer films

Interface mitigation effects on ion irradiation induced damage are explored in TiN/MgO nanolayer thin films with nanolayer thickness varied from 10 nm to 50 nm. After ion irradiation with He ions to a fluence of 4 × 10 ¹⁶ cm^-2 at 50 keV, no hardness variation is observed in the nanolayer samples based on the nano-indentation measurement, and high resolution TEM indicates no obvious ion damage in the MgO layers in the nanolayered samples. However, single layer MgO film shows a significant hardness increase of ∼20% and high density point defect clusters (∼5 nm) are clearly identified. These results suggest that, in this system, nanolayer interfaces could act as effective point defect sinks and be responsible for the enhanced radiation tolerance properties.