Dopant Loss Mechanism in n[sup +]∕p Germanium Junctions during Rapid Thermal Annealing

The phenomenon of severe dopant loss during rapid thermal annealing of phosphorus-implanted germanium has been investigated. Dopant activation improves for temperatures above and reaches 100% activation for samples annealed at . However, a heavily defective junction with approximately 50% dopant loss is recorded. Although surface passivation of the implanted germanium using plasma-enhanced chemical vapor deposited silicon dioxide did not prevent the dose loss, it assisted in the achievement of defect-free, single-crystal germanium with improved electrical characteristics at a reduced thermal budget. Phosphorus introduced into germanium via solid-state diffusion from phosphosilicate glass did not exhibit dose loss upon rapid thermal annealing, suggesting that dose loss could be an effect of implant damage.