Dopant loss mechanism in n(+)/p germanium junctions during rapid thermal annealing

Abstract

The phenomenon of severe dopant loss during rapid thermal annealing of phosphorus-implanted germanium has been investigated. Dopant activation improves for temperatures above 500 degrees C and reaches 100% activation for samples annealed at 600 degrees C. 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. (c) 2005 The Electrochemical Society. All rights reserved.