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

We report the growth of epitaxial metastable B1 NaCl structure TaN(001) lay ers. The films were grown on MgO(001) at 600 degrees C by ultrahigh vacuum reactive magnetron sputter deposition in mixed Ar/N-2 discharges maintained at 20 mTorr (2.67 Pa). X-ray diffraction and transmission electron microsc opy results establish the epitaxial relationship as cube-on-cube, (001)(TaN )parallel to(001)(MgO) with [100](TaN)parallel to[100](MgO), while Rutherfo rd backscattering spectroscopy shows that the layers are overstoichiometric with N/Ta=1.22 +/- 0.02. The room-temperature resistivity is 225 mu Omega cm with a small negative temperature dependence between 20 and 400 K. The h ardness and elastic modulus, as determined by nanoindentation measurements, are 30.8 +/- 0.9 and 457 +/- 16 GPa, respectively. (C) 1999 American Insti tute of Physics. [S0003-6951(99)04450-2].