Self-organized lamellar structured tantalum-nitride by UHV unbalanced-magnetron sputtering

The structure of the TaNx film transformed from B1-NaCl δ-TaNx to lamellar structured B1-NaCl δ-TaNx+ hexagonal ɛ-TaNx or B1-NaCl δ-TaNx+hexagonal γ-TaNx with increasing ion energy at the same nitrogen fraction fN2. The hardness of the films also increased by the structural change. At the nitrogen fraction of 0.1-0.125, the structure of the TaNx films was changed from δ-TaNx+ɛ-TaNx to δ-TaNx+γ-TaNx with increasing ion energy. However, at the nitrogen fraction of 0.15, the film structure did not change from δ-TaNx+ɛ-TaNx over the whole range of the applied ion energy. The hardness increased significantly from 21.1 to 45.5 GPa with increasing ion energy.