Interface relationship between TiN and Ti substrate by first-principles calculation

Abstract

In this paper, the lattice misfits between Ti and TiN interfaces were calculated by the Bramfitt two-dimensional lattice misfit theory. The adhesive work (Wad), interfacial energy (γ), electronic property and bonding characteristic of Ti(0 0 0 1)/TiN(1 1 1) interface were also investigated by first-principles calculation. The results show that, the lattice misfit of Ti(0 0 0 1)/TiN(1 1 1) interface is only 2.46%, which indicates that Ti(0 0 0 1) and TiN(1 1 1) faces can make good lattice matching. Based on three atomic stacking modes (OT-, SL- and TL-sites) and two terminations of TiN(1 1 1) face, six kinds of Ti(0 0 0 1)/TiN(1 1 1) interface models were established. The interfacial bonding strength and stability of the Ti(0 0 0 1)/TiN(1 1 1) N-terminated (Ti/N) interface models are all larger than those of Ti(0 0 0 1)/TiN(1 1 1) Ti-terminated (Ti/Ti) ones. Wad of the N-TL interface (Ti structure contacting with N-terminated structure of TiN with TL site) is the largest (7.97 J/m2), while the relaxed interfacial separation (d0) is the smallest (1.181 Å) and the γ is the smallest (−3.86 J/m2), which indicates that the bonding strength and stability of the N-TL interface are the largest in all interface models. Additionally, the interface bonds of Ti/Ti interface models are weak, and their interfacial strength and stability are relatively weak. The bonding strengths of the three interface models of Ti/N interfaces are larger than that of the Ti/Ti interfaces, which forms a strong polar covalent bond and a metallic one.