The extended defects which were introduced by the implantation of 1.5MeV B or 2.6MeV P ions were investigated by using plan-view and cross-sectional transmission electron microscopy and etching methods. The threading dislocations were identified as being long dislocation dipoles which were generated in the region of the projected ion range. The formation of threading dislocations was shown to exhibit a marked dependence upon the implantation dose and O concentration. After annealing at 900C, a high density of threading dislocations was formed by the implantation of B or P to doses ranging from 5 x 1013 to 2 x 1014/cm2 or from 5 x 1013 to 3 x 1014/cm2, respectively. The threading dislocation density in B-implanted Czochralski Si substrates was found to be much higher than that in B-implanted epitaxial Si substrates. This difference was attributed to the strong pinning effect of O, which immobilized dislocations in Czochralski substrates. Because P was also efficient at pinning dislocation motion, a high density of threading dislocations was observed even in epitaxial Si substrates after P implantation. The use of 2-step annealing, with a first step at 700C (to precipitate O) and a second step at 900C, was very effective in eliminating the formation of threading dislocations.

J.Y.Cheng, D.J.Eaglesham, D.C.Jacobson, P.A.Stolk, J.L.Benton, J.M.Poate: Journal of Applied Physics, 1996, 80[4], 2105-12