A model was developed for the interstitial migration of ion-implanted boron during the rapid thermal annealing of silicon layers amorphized by the implantation of germanium. It was proposed that boron interstitials were continuously generated during the whole annealing period due to the dissolution or rearrangement of the clusters of dopant atoms which were formed in the ion-implanted layer. These were at an impurity concentration which was above the solubility limit in the initial stage of treatment. The local elastic stresses arising from the small atomic radius of boron also contributed to the generation of boron interstitials. A simulation was performed of the boron redistribution during thermal annealing (60s, 850C). The calculated profile agreed well with the experimental data; thus confirming the adequacy of the proposed model. The parameters of interstitial boron diffusion were deduced. The average migration length of non-equilibrium boron interstitials was 12nm. Also, 1.8 to 2% of the boron atoms became interstitial, participated in fast interstitial migration, and then became immobile again to occupy substitutional lattice sites or form complexes with crystal lattice defects.

Modeling of the Long-Range Interstitial Migration of Ion Implanted Boron. O.I.Velichko, N.V.Kniazhava: Computational Materials Science, 2010, 48[2], 409-12