Effect of annealing temperature ramp rate on bubble formation in helium-implanted silicon

We have implanted 3He into Si(100) at 1.0 MeV ion energy and to fluences ranging between 2x1015 and 2x1016 cm-2, followed by annealing at 700 deg. C. Heating ramp rates have been systematically varied over more than two decades (0.3 deg. C/s to 100 deg. C/s) at each fluence. The retention of 3He is measured through the 3He(d,p)4He nuclear reaction yield. We show that gas retention can be varied by more than an order of magnitude even while the other anneal parameters--anneal temperature and anneal time--are maintained constant. Cross-sectional scanning electron micrographs confirm the presence of planetarylike cavity structures at a depth closely matching that calculated for the damage peak