Surface blistering in ZrSiN nanocomposite films irradiated with He ions

Abstract

In the present work, the influence of silicon content on the surface blistering of ZrSiN nanocomposite films after He ion irradiation (energy of 30 keV and doses up to 8 × 1016 cm−2) and post-radiation annealing at the temperature of 600 °C was investigated. Using SEM, TEM and AFM methods, the influence of amorphous/crystalline boundaries on the formation of blisters in the n-ZrN/a-Si3N4 nanocomposites was studied. ZrSiN nanocomposite films (~300 nm thick) were deposited at 600 °C onto (001) Si wafers by reactive unbalanced magnetron sputtering technique. Silicon concentration was varied from 7.1 to 23.1 at.%. While helium ion irradiation (at the dose of 8 × 1016 cm−2) did not change the surface morphology of the nanocomposite films, the alteration of the surface was observed after vacuum annealing. It was revealed that post-radiation annealing (600 °C) of ZrN and Si3N4 mononitride films resulted in surface blistering at the dose of 5 × 1016 cm−2. Rather low blister density (0.017 μm−2) after post-radiation annealing at the dose of 5 × 1016 cm−2 was also observed for the nanocomposite film with 7.1 at.% Si content. As the irradiation dose increased up to 8 × 1016 cm−2, the surface density of blisters raised significantly (0.53 μm−2). It was found that increasing of Si concentration in the nanocomposite films was beneficial for their radiation resistance. The ZrSiN nanocomposite film with maximum Si content of 23.1 at.% was the most stable, with no sign of surface blistering being detected.