DEFECTS IN GE-IMPLANTED SI STUDIED BY SLOW POSITRON IMPLANTATION SPECTROSCOPY()

Slow positron implantation spectroscopy has been applied to the invest igation of point defects formed during the synthesis of buried SiGe al loy layers in Si by high-dose Ge+ implantation and post-amorphization with Si+. It is seen that omitting the post-amorphization stage prior to annealing leaves a damaged layer, containing open volume defects, e xtending beyond the Ge+-implanted overlayer. Provided that the Ge dose is low enough to allow planar crystal regrowth, post-amorphization ap pears to inhibit defect formation. Samples implanted with higher doses contain as-yet unidentified defects.