RECRYSTALLIZATION OF IMPLANTED AMORPHOUS SILICON LAYERS .2. MIGRATION OF FLUORINE IN BF2+-IMPLANTED SILICON

Fluorine distribution profiles for silicon implanted with BF +2 have been measured by SIMS as a function of anneal temperature and time. Anomalous migration of fluorine is observed in samples having amorphized layers after implantation. Outdiffusion of fluorine occurs during recrystallization of the amorphous layer, and fluorine collects in regions of residual damage during annealing. This gettering of fluorine by defects illustrates the residual damage below the amorphized layer in samples implanted at room temperature is more difficult to anneal out than that in samples implanted at lower temperture (∼-110°C).