Radiation-enhanced diffusion of Sb and B in silicon during implantation below400°C

Abstract

We have investigated dopant-defect interactions during ion implantation of silicon into silicon by monitoring the radiation-enhanced diffusion (RED) of Sb and B dopant diffusion markers. The RED of these dopant markers has been investigated as a function of implant temperature $(25--400\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}),$ implant dose ${(10}^{14}--{10}^{16}{\mathrm{cm}}^{\ensuremath{-}2}),$ and implant energy (2 MeV or 40 keV Si ions). Experimental results are interpreted with the aid of atomistic simulations that include detailed defect-defect and dopant-defect interactions. We demonstrate that RED of B and Sb occurs at lower temperatures than previously reported (below $100\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$ and $200\ifmmode^\circ\else\textdegree\fi{}\mathrm{C},$ respectively) and the magnitude of this effect increases with implant temperature and dose. We also demonstrate that RED of these dopants is only measurable within the damage cascades of the implanted ions, i.e., there is no observable long-range diffusion of defects during implantation. Significant differences in dose, temperature, and depth dependence between B and Sb RED occur. Comparison of experimental and simulation results indicates that these differences are due to the diffusion mechanisms of the dopants. Simulations also demonstrate that the formation and dissolution of defect clusters during implantation plays a significant role in the observed temperature and dose dependencies.