Implantation and transient B diffusion in Si: The source of the interstitials

Abstract

Implanted B and P dopants in Si exhibit transient enhanced diffusion (TED) during initial annealing, due to Si interstitials being emitted from the region of the implant damage. The structural source of these interstitials has not previously been identified. Quantitative transmission electron microscopy measurements of extended defects are used to demonstrate that TED is caused by the emission of interstitials from specific defects. The defects are rodlike defects running along 〈110〉 directions, which consist of interstitials precipitating on {311} planes as a single monolayer of hexagonal Si. We correlate the evaporation of {311} defects during annealing at 670 and 815 °C with the length of the diffusion transient, and demonstrate a link between the number of interstitials emitted by the defects, and the flux of interstitials driving TED. Thus not only are {311} defects contributing to the interstitial flux, but the contribution attributable to {311} defect evaporation is sufficient to explain the whole of the observed transient. The {311} defects are the source of the interstitials.

Continuum based modeling of silicon integrated circuit processing: An object oriented approach

“…Fig. 6 shows the comparison of measured {311} interstitial and defect dose [11] with simulations from FLOOPS [12].…”

“…The {311} defects store interstitials and release them at a rate that is similar to the duration of TED [11]. It is important to model both the nucleation and growth of these defect structures as well as their dissolution.…”

“…For example, the 311 defect has become the popular explanation for transient enhanced di usion behavior [11]. A ®rst-order model for this defect was implement in approximately one man-week [12].…”

Recombination of Point Defects via Extended Defects and Its Influence on Dopant Diffusion

“…Modeling of transient enhanced diffusion has changed from a point-defect-centcred view to the understanding that the storage of point defects in extended defects is the main mechanism determining the kinetics of the phenomenon [1]. Extended defects form by agglomeration of intrinsic point defects generated by the ion implantation process.…”

Modeling of Ion Implantation and Diffusion in Si

“…The damage produced during ion implantation can play an important role on the diffusion of dopants during high temperature treatments. In particular, one of the key problems in the development of ultrashallow junctions is transient enhanced diffusion [2,3,4] of dopants during the activation stage. The defects produced during implantation interact with the dopants and induce their migration over long distances, changing the initial implantation profile.…”