Formation and microstructural development of TiSi₂ in (111)Si by Ti ion implantation and annealing at 950 °C

A transmission electron microscopy study of the microstructural development for (111)Si wafers implanted with Ti ions and annealed subsequently at 950 °C is presented. The as-implanted wafers have a Ti-rich amorphous layer at the surface with embedded silicides, which correspond to a crystalline form of TiSi₂ that has not been reported previously. Below this lies a Ti-lean crystalline layer with extensive radiation damage. The annealed layers have large incoherent islands of C54 TiSi₂, with a layered microstructure in the Si between them consisting of twins, then topotaxial silicides, then dislocation loops. It is proposed that this microstructure arises from silicide growth prior to epitaxial regrowth, whereas for the continuous epitaxial films observed previously at lower annealing temperatures, epitaxial regrowth precedes silicide development.