The diffusion of Pt into lightly damaged regions of n-type material was investigated by using deep-level transient spectroscopy and capacitance-voltage profiling of Pt-silicide Schottky diodes. The diodes had been implanted through the junction (with O, F, or Cl ions), and had then been annealed at 700C. The distribution of the in-diffused Pt was deduced by monitoring electron emissions from the acceptor level (EC-ET = 0.23eV) of Pt which occupied a distorted substitutional configuration. At a typical implantation dose of about 1011/cm2), an increased accumulation (by about 2 orders of magnitude) of Pt was observed; as compared with diffusion into non-implanted material. It was found that the in-diffused Pt was distributed almost in parallel with the vacancy distribution which was generated during implantation. This apparent decoration of the primary damage profile occurred without the simultaneous introduction of other electrically active defects at a comparable scale. It was concluded that the residual damage which was present during annealing was sufficient to promote the accumulation to saturation of substitutional Pt in the region of the primary implantation damage. It was suggested that this so-called guided in-diffusion effect might be exploited for device processing.

K.B.Nielsen, B.Holm: Materials Science Forum, 1995, 196-201, 1985-90