Growth and physical properties of epitaxial metastable cubic TaN(001)

We report the growth of epitaxial metastable B1 NaCl structure TaN(001) layers. The films were grown on MgO(001) at 600 °C by ultrahigh vacuum reactive magnetron sputter deposition in mixed Ar/N2 discharges maintained at 20 mTorr (2.67 Pa). X-ray diffraction and transmission electron microscopy results establish the epitaxial relationship as cube-on-cube, (001)TaN∥(001)MgO with [100]TaN∥[100]MgO, while Rutherford backscattering spectroscopy shows that the layers are overstoichiometric with N/Ta=1.22±0.02. The room-temperature resistivity is 225 μΩ cm with a small negative temperature dependence between 20 and 400 K. The hardness and elastic modulus, as determined by nanoindentation measurements, are 30.8±0.9 and 457±16 GPa, respectively.