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

Abstract

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 hetero-epitaxially 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.