Atomistic simulations of extrinsic defects evolution and transient enhanced diffusion in silicon

Abstract

In this letter, a physically based model describing the kinetic evolution of extrinsic defects during annealing is presented. The fundamental concepts of Ostwald ripening and formation energy of extrinsic defects are combined in this model, which has been tested against some classical experiments concerning (i) transient enhanced diffusion (TED) of dopants in conjunction with the dissolution of {113} defects and (ii) the “pulsed” TED observed in the case of ultralow energy implants where the surface acts as a strong sink for the silicon interstitial atoms. We show that a full understanding of the formation and the evolution of extended defects leads to a correct prediction of dopant enhanced diffusion in all experimental conditions.

Evidence on the mechanism of boron deactivation in Ge-preamorphized ultrashallow junctions

“…15,18 The model uses continuum equations, one for each defect size, to describe the capture and loss of interstitials by extended defects ͑interstitial clusters, ͕113͖ defects and dislocation loops͒ and thus the Ostwald ripening and dissolution of the defects during thermal annealing. A substantial part of the released interstitials diffuses toward silicon surface, where they recombine.…”

Prediction of boron transient enhanced diffusion through the atom-by-atom modeling of extended defects

“…When n increases, such formation energies tend towards values expected for small ͕113͖ defects. The formation energy of the ͕113͖s is taken from Colombeau et al 10 and tends towards 0.65 eV for large sizes. The formation energies of the dislocation loops are given in Ref.…”

On the origin of dislocation loops in irradiated materials: A point of view from silicon

“…Once these {1 1 3}s are formed, they grow in size and reduce their density, again as a result of ripening. Their total energy can be analytically calculated from their crystallographic characteristics i.e., by taking into account the two edge dislocations plus the two mixed dislocations plus the stacking fault energy which altogether define them [19]. This formation energy curve gently tends towards its asymptotical limit at 0.6 eV, as shown in Fig.…”