Interfacial reactions for the non-stoichiometric TiB x /(100)Si system

In order to evaluate the interfacial reactions in the TiB ₓ /(100)Si system and the thermal stability of non-stoichiometric TiB ₓ films (0 ≤ B/Ti ≤ 2.5), TiB ₓ /Si samples prepared by a co-evaporation process were annealed in vacuum at temperatures between 300 and 1000°C. The solid phase reactions were investigated by means of sheet resistance, X-ray diffraction, transmission electron microscopy, X-ray photo-electron spectroscopy, and stress measurement. For TiB ₓ samples with a ratio of B/Ti ≥ 2.0, an apparent structural change is not observed even after annealing at 1000°C for 1 h. For samples with a ratio of B/Ti < 2.0, however, there are two competitive solid phase reactions: the formation of a titanium silicide layer at the interface and the formation of a stoichiometric TiB₂ layer at the surface, indicating the salicide [Formula: see text] process. The sheet resistance and the film stress in the Ti/Si and TiB ₓ /Si systems are well explained by the solid phase reactions.