The distribution of B atoms in samples which had previously been implanted with F+ and Ne+ to doses of 1.2 x 1013 or 1.5 x 1015/cm2 was investigated, before and after annealing, by means of secondary ion mass spectrometry. After annealing at 900C, a strong dependence of the B redistribution rate upon F concentration was observed. It was found that the presence of F decreased B redistribution, while that of Ne (which was close to F in the periodic table, but which was inert) did not. When post-implantation annealing was carried out at 1000C, the B distribution did not depend upon the type of previously implanted ion. At this temperature, F atoms left the crystal. The results showed that the redistribution of B which was implanted into Si depended upon the chemical activity of the impurity which was present in a crystal, and upon its concentration.

The Effect of Fluorine on the Redistribution of Boron in Ion-Implanted Silicon. L.J.Krasnobaev, N.M.Omelyanovskaya, V.V.Makarov: Journal of Applied Physics, 1993, 74[10], 6020-2