Single-crystal growth of NaCl-structure Al-Cr-N thin films on MgO(001) by magnetron sputter epitaxy

摘要

Single-crystal NaCl-structure Al_(0.68)Cr_(0.32)N thin films were deposited onto MgO(00l) substrates. The firms exhibit cube-on-cube epitaxial growth with an initial pseudomorphic strained layer before complete relaxation into an isotropic lattice parameter of 4.119 A as shown by symmetric high-resolution X-ray diffraction and asymmetric reciprocal space maps. The relaxation proceeds via a threading dislocation network as revealed by transmission electron microscopy. Films of 900 run thickness have a hardness of 32.4 +- 0.5 GPa, an elastic modulus of 460.8 +- 5 GPa, and a room-temperature resistivity of 2.7 x 10~3 OMEGA cm as determined by nanoindentation and four-point probe measurements, respectively.