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

摘要

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 $(underline s elf - underline {al} igned silunderline {icide} )$ 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.