Epitaxial growth and electrical-transport properties of Ti7Si2C5 thin films synthesized by reactive sputter-deposition

Epitaxial predominantly phase-pure Ti7Si2C5 thin films were grown onto Al2O3(0 0 0 1) by reactive magnetron sputtering. The c-axis lattice constant is ∼60.2 Å; the Ti7Si2C5 unit cell comprises alternating Ti3SiC2-like and Ti4SiC3-like half-unit-cell stacking repeated three times. Elastic recoil detection analysis showed a few percent of nitrogen in the films from the acetylene gas used. The nitrogen-induced stabilization mechanism for Ti7Si2C5 relative to Ti3SiC2 and Ti4SiC3 is discussed. Electrical-transport measurements showed metallic temperature dependence and a room-temperature resistivity of ∼45 μΩ cm.