Role of the Si–Si bond stability in the first stages of Ti diffusion on a Si(1 1 1) 2 × 1 surface. A periodic DFT study

A periodic Density Functional Theory (DFT) study, using Generalized Gradient Approximation (GGA), of the Ti deposition on a clean 2 × 1 reconstructed Si (1 1 1) surface was carried out. Results indicate that as in the case of the Si(0 0 1) surface, a TiSi monolayer is formed at 6.8 × 1014 Ti atom cm−2 which shows its high reactivity in presence of Ti even at RT. However, the TiSi interface on the Si(1 1 1) presents Ti–Ti and Si–Si interactions forming atom rows in a zigzag arrangement. Ti deposition on the TiSi interface suggests that remaining Si–Si bonds on the surface could play a very important role in the Ti diffusion on the Si surface.