Low temperature epitaxial growth of Cantor-nitride thin films by magnetic field assisted magnetron sputtering

Abstract

Low-temperature epitaxial growth of multicomponent alloy-based thin films remains an outstanding challenge in materials science and is important for established fundamental properties of these complex materials. Here, Cantor nitride (CrMnFeCoNi)N thin films were epitaxially grown on MgO(100) substrates at low deposition temperature by magnetic-field-assisted dc-magnetron sputtering, a technique where a magnetic field is applied to steer the dense plasma to the substrate thereby influencing the flux of Ar-ions bombarding the film during growth. Without ion bombardment, the film displayed textured growth. As the ion flux was increased, the films exhibited epitaxial growth. The epitaxial relationship between film and substrate was found to be cube on cube (001)film||(001)MgO, [100]film||[100]MgO. The epitaxy was retained up to a thickness of approximately ∼100 nm after which the growth becomes textured with a 002 out-of-plane orientation. The elastic constants determined by Brillouin inelastic light scattering were found to be C11 = 320 GPa, C12 = 125 GPa, and C44 = 66 GPa, from which the polycrystalline Young’s modulus was calculated as 204 GPa and Poisson's ratio = 0.32, whereas available elastic properties still remained very scarce.