Diffusion of elements implanted in amorphous titanium disilicide

The usual Si dopants, B, P, As, and Sb, plus Ge were implanted into thick (400 nm) TiSi2 layers deposited in an amorphous state by sputtering from a compound target. Samples with the various implants were annealed at temperatures from 300 to 700°C and analyzed both by transmission electron microscopy and secondary ion spectroscopy. The annealed samples display a very large grain size, which complicates the interpretation of the concentration profiles obtained by SIMS. In the case of a high dose of B (1 × 1016 atoms/cm2 at least), there is an indication of grain boundary transport occurring mostly in the initial stage of the heat treatments, followed by phenomena dominated by a reduced solubility in the terminal large-grained matrix. With all elements, except Sb, evidence of diffusion is obtained at 400°C. Germanium diffusion is even observed at 300°C. © 1993.