Low temperature growth of Cu thin films on TiN(001) templates: Structure and energetics

Synthesis of metal/ceramic interfaces with well-defined structural characteristics is an important step toward understanding the energetics and mechanical response of such interfaces. We used ultra-high-vacuum magnetron sputter deposition to grow elemental Cu thin films onto single crystal TiN(001) thin film templates, grown heteroepitaxially onto single crystal MgO(001) substrates. Structure of the Cu thin films grown on TiN(001) templates was examined as a function of the growth temperature. At close to room temperature, we observed the previously reported cube-on-cube orientation relationship between Cu and TiN, with Cu(001)//TiN(001). At a slightly elevated temperature, we observed a new Cu-TiN orientation relationship with Cu(110)//TiN(001) that, to the best of our knowledge, is reported here for the first time. Accompanying molecular dynamics simulations with modified embedded atom method potentials newly developed for the Cu-TiN system showed the influence of nanoscale twinning and lattice strain on structure and interfacial energetics of Cu/TiN bicrystals. Controlled growth of metal/ceramic bicrystal thin films offers an opportunity for systematic testing of the mechanical response of metal/ceramic interfaces with better defined structural characteristics.