Vacancy defects in solid-phase epitaxial grown layers of self-implanted Si

A method for preparing shallow dopant distributions via solid-phase epitaxi al growth (SPEG) following amorphization by low-energy Si self-ion implanta tion leaves defects that can lead to unwanted dopant impurity diffusion. Th e double implant method for SPEG [O. W. Holland et al., J. Electron. Mater. 25, 99 (1996)] uses both low- and high-energy Si self-ion implantation to remove most of the interstitials. Nevertheless, we find that measurable cry stalline imperfections remain following the SPEG annealing step. Measuremen ts of defect profiles using variable-energy positron spectroscopy show that there are divacancy-impurity complexes in the SPEG layer and V-6 and large r vacancy clusters near the SPEG-crystalline interface. These measurements should be useful for modeling the diffusion of dopant atoms and for fine tu ning the double implant parameters. (C) 1999 American Institute of Physics. [S0003-6951(99)01707-6].