Universidad de Valladolid

Universidad de Valladolid

Boron activation and redistribution during thermal treatments after solid phase epitaxial regrowth

M. Aboy, L. Pelaz, J. Barbolla, R. Duffy and V. C. Venezia

Materials Science and Engineering: B 124-125, 205 (2005)


Abstract:

The solid phase epitaxial regrowth (SPER) technique achieves active B concentrations up to a few times 1020 cm−3 after low-temperature recrystallization process, while higher B concentration regions remain immobile forming electrically inactive B clusters during SPER. Kinetic Monte Carlo simulations on B diffusion and activation in preamorphized Si during annealing after SPER are presented, providing a good insight into mechanisms that drive these phenomena. Simulations show that the presence of end of range (EOR) defects, still present beyond the amorphous/crystalline interface after recrystallization, leads to additional deactivation during subsequent anneal treatments. Moreover, B uphill diffusion towards the surface is observed in the medium concentration region, while downhill diffusion occurs in the tail region of the B profile. During prolonged anneals B activation decreases until it reaches a minimum, which becomes lower as the annealing temperature reduces. Finally, when EOR defects dissolve or reach very stable configurations such us dislocation loops, B reactivation is observed as well as B tail diffusion.

DOI: 10.1016/j.mseb.2005.08.067

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