Phosphorus diffusion was studied using conventional thermal processing, and laser-annealing by pulsed nanosecond Nd:YAG laser. The profiles were measured using secondary ion mass spectroscopy, the sheet resistance was estimated by using the van der Pauw method and structural defects were monitored via transmission electron microscopy. The study covered the range from 440 to 750C, and it was possible to simulate the dopant profiles within that range; taking account of a quadratic dependence of the P diffusion coefficient upon the free electron concentration. To achieve the latter, account was taken of the dopant activation dependence upon temperature, as well as dopant pile-up near to the surface and dopant-loss due to out-diffusion during annealing. Combined laser thermal treatment above the melting point, before conventional annealing, permitted the elimination of implantation damage, so that the influence of defects upon both transient dopant diffusion and out-diffusion could be isolated.

Modeling and Experiments on Diffusion and Activation of Phosphorus in Germanium. P.Tsouroutas, D.Tsoukalas, I.Zergioti, N.Cherkashin, A.Claverie: Journal of Applied Physics, 2009, 105[9], 094910

Table 15

Diffusivity of P in Ge

Table 16

Diffusivity of Sb in Ge