Copper gettering in silicon at half of the projected ion range induced by helium implantation

Damage has been observed in keV He ₊ ion-implanted Si away from the projected ion range Rp, mainly around Rp/2. Cu gettering has been used for the detection of irradiation defects which are formed during rapid thermal annealing (RTA) of 800°C/10 min. The transmission electron microscopy (TEM) micrographs show no visible defects at Rp/2. The Cu gettering peak at Rp/2 is well known for MeV-ion-implanted and annealed Si (Rp/2 effect). In this study the corresponding effect is observed for low energy implantation of a light ion like He. The mechanism of the cavity formation when He is implanted into silicon and its influence to the implantation induced point defects recombination during subsequent annealing is discussed.