Average P diffusivities after implantation in <100> Ge were measured for long annealing times (3 to 10h) at 600 to 800C. Considerable dose loss after annealing below 800C was also observed. A diffusion model, using an extrinsic diffusivity coefficient combined with a segregation component between the Ge and the oxide (to account for dopant loss), was found to be sufficient to explain completely the observed diffusion profiles. The best-fit diffusivity and segregation coefficients were reported for this model and the diffusivities were found to be over an order of magnitude slower than those measured after rapid thermal annealing (i.e., annealing times of only a few seconds). It was proposed that this disagreement of diffusivities between short- and long-term annealing was due to implant damage; perhaps similar to well-known transient enhanced diffusion effects observed in silicon.

Accurate Modelling of Average Phosphorus Diffusivities in Germanium after Long Thermal Anneals - Evidence of Implant Damage Enhanced Diffusivities. M.S.Carroll, R.Koudelka: Semiconductor Science and Technology, 2007, 22, S164-7