Ab initio calculations of the β-SiC(001)/Ti interface

Ab initio pseudopotential calculations of the beta-SiC(001)/Ti interface have been performed, and are compared with our preceding results of the SiC(001)/Al interface [Phys. Rev. B 57, 2334 (1998)]. The C-terminated and Si-terminated interfaces have quite different features, similarly to the SiC(001)/Al interface. For the Si-terminated interface, the Si-Ti bond has a metallic character similar to the Si-terminated SiC/Al interface. For the C-terminated interface, the C-Ti bond has strong p-d sigma covalent interactions between C 2p and Ti 3d oribitals like bulk TiC. The C-Ti bond length is very small like bulk TiC although the back Ti-Ti bond is greatly weakened. The adhesive energy of this interface is much larger than the other SiC/Ti and SiC/Al interfaces. It can be said that for the C-terminated interface, a solid-state reaction can occur even at low temperature only at the interface layers, which is in good agreement with experiments. For the Schottky-barrier height, the difference between the C-terminated and Si-terminated interfaces has a similar tendency to the SiC/Al interface, which can be explained by the difference in the interface dipole.