Novel Dopant Activation of Heavily Dopedp+-Si by High Current Densities

Novel dopant activation in the heavily boron-doped ${p}^{+}$-Si was created by applying an electrical current of high current density. The ${p}^{+}$-Si was implanted by 40 keV ${\mathrm{BF}}_{2}^{+}$ of $5\ifmmode\times\else\texttimes\fi{}{10}^{15}\phantom{\rule{0ex}{0ex}}\mathrm{ions}/{\mathrm{cm}}^{2}$ and annealed at 900 \ifmmode^\circ\else\textdegree\fi{}C for 30 min to obtain a partial boron activation. For additional activation, we gradually applied current until a current density of $5\ifmmode\times\else\texttimes\fi{}{10}^{6}\phantom{\rule{0ex}{0ex}}\mathrm{A}/{\mathrm{cm}}^{2}$ was achieved. The resistance of the ${p}^{+}$-Si responded by gradually increasing, then decreasing with a precipitous drop. The resistance was reduced by a factor of 5 to 18. Mechanisms of the novel dopant activation are proposed.