The defect evolution upon annealing of low-energy amorphizing Ge implants into Si was studied by using plan-view transmission electron microscopy. Implants with energies of 5 to 30keV, at an amorphizing dose of 1015Ge+/cm2, were annealed (750C, 10s to 6h). For implantation energies of 10 and 30keV, the defects formed clusters which evolved into {311} defects that subsequently dissolved or formed stable dislocation loops. However, when the implantation energy was decreased to 5keV, the interstitials evolved from clusters to small unstable loops which dissolved within a small time window and did not form {311} defects. In order to determine the effect of the free surface as an interstitial recombination sink for 5keV implants, the amorphous layer of a 10keV implant was lapped to less than the thickness of a 5keV amorphous layer and then annealed. It was found that the defect dissolution observed for the 5keV implant energy depended upon the implantation energy and not upon the proximity of the end-of-range damage to the surface. The activation energy for the observed rapid defect dissolution at 5keV was calculated to be 1.0eV.

Defect Evolution of Low-Energy Amorphizing Germanium Implants in Silicon. A.C.King, A.F.Gutierrez, A.F.Saavedra, K.S.Jones, D.F.Downey: Journal of Applied Physics, 2003, 93[5], 2449-52