Effect of end of range loops on transient enhanced diffusion in Si

In the Si IC industry today all highly doped, ion implanted regions were amorphized at one point. Upon annealing, it has generally been believed that dopant in the regrown silicon does not show any enhanced diffusion. The accepted model was that the end of range (EOR) dislocation loop density was sufficient to prevent the back flow of interstitials toward the surface by acting as a blocking layer. In this paper it is shown that conditions exist where significant transient enhanced diffusion (TED) of dopants in regrown silicon can occur for amorphizing implants of Si and Ge. The effect of implantation temperature and species on the amount of TED in the regrown silicon is studied. Comparison of SIMS and TEM results indicates the end of range damage is the source of the TED not defects grown in during the solid phase epitaxial regrowth process. In particular the dissolution of <311> defects in the EOR damage appears to account for a significant amount of the TED. Comparison of the magnitude of the back flow from several different experiments is presented. There appears to be an exponential dependence of the amount of back flow on the dislocation loop density in the EOR layer. Increasing loop density results in a decreasing back flow.