Blister Formation in Zirconium, Aluminum and Chromium Nitride Films Irradiatedwith Helium Ions
The work is devoted to the study of blister formation in ZrN, AlN, CrN films formed by reactive magnetron sputtering. The surface morphology and cross-section microstructure of the mononitride films after irradiation with He ions (energy 40 keV and doses of 3 × 1017−1.1 × 1018 cm–2) at room temperature were studied using scanning, atomic-force and transmission electron microscopy. The critical doses of blistering for ZrN (6 × 1017 cm–2), AlN (5 × 1017 cm–2), CrN (6 × 1017 cm–2) films were determined. The high density of blisters in ZrN films leads to the merging of neighboring blisters (average size 0.75 μm) and the formation of large blisters (average size 1.35 μm). The blisters in AlN films have a regular round shape (average size 1.7 μm). СrN films are characterized by the presence of open blisters having a two-level structure: the top blister with a diameter of 2−10 μm and the bottom one – 1.2 μm. The results of the TEM studies indicate that irradiation of the films with He ions (40 keV) and subsequent vacuum annealing leads to the formation of radiation pores chains filled with helium in the Rp region. The formation of extended cracks in the region of Rp in ZrN caused by interbubble fracture due to the presence of high excess pressure in the pores located at depth close to Rp.