Lateral SPE recovery of implanted source/drain in thin SOI MOSFETs

Recrystallization of BF₂-, As-, and Si-implanted source/drain regions in very thin SOI layers with Si-gates has been studied using observation from conventional and high-resolution cross-sectional TEMs. The implanted regions were completely amorphized and then recrystallized through a lateral solid-phase epitaxy (L-SPE) by using a gate-masked single crystal SOI region as a seed. In the very early annealing stage, the amorphous/crystalline interfaces of the L-SPE regrowth along ⟨110⟩ and ⟨100⟩ directions changed into the interfaces having faceted {111} and {110} planes, During the L-SPE, {311} defects with lengths of 3 to 4 nm were formed under the gate within a region of 60 to 70 nm from the mask edge and they could not be completely eliminated without a high-temperature annealing of 900°C