Scanning tunnelling microscopy was used to provide atomic-scale views of the reaction and diffusion of Ti on (001) at the monatomic adsorption stage. Two monatomic adsorption structures, below and above 440K, were found. The characteristic adsorption below 440K involved a Ti atom at the pedestal site on a dimer row. The high-temperature adsorption structure above 440K involved adsorption at a dimer vacancy that was induced by a dimer ejection process on the structural conversion path. The high-temperature adsorption structure exhibited a 1-dimensional hopping motion along dimer rows. Measurements of the hopping rate yielded a diffusion activation energy and pre-factor of 1.8eV and 1014/s, respectively. The growth features and diffusion mechanism were interpreted in terms of Ti-Si bond formation.

Reactive Adsorption and Diffusion of Ti on Si(001) by Scanning Tunneling Microscopy. K.Ishiyama, Y.Taga, A.Ichimiya: Physical Review B, 1995, 51[4], 2380-6

Table 115

Diffusivity of Ti in Si