On the relation between dopant anomalous diffusion in Si and end-of-range defects

Abstract

The goal of this paper is to answer questions regarding the relation between “anomalous” diffusion and EOR defects. Knowing the type and origin of these defects allows one to understand why and how they affect dopant diffusion. Hence, it is possible to find out under which experimental conditions their density can be minimized and most importantly to develop physical models for dopant diffusion taking into account the behaviour of EOR defects during annealing. Indeed, these dislocations loops are efficient trapping sites for boron and this cannot be neglected in realistic simulations. Upon annealing, these defects increase in size and reduce their density and this through the emission and capture of Si interstitials. Thus, EOR defects can be seen as reservoirs able to maintain a high supersaturation of free self-interstitials during their dissolution. This point defect supersaturation induces a strong increase of boron diffusivity through the formation of excess Si(1)-B pairs. Thus, the experimentally observed macroscopic motion of dopant is the result of the two competing phenomena.