Interaction of the end of range defect band with the upper buried oxide interface for B and BF_2 implants in Si and silicon on insulator with and without preamorphizing implant

摘要

The International Roadmap for Semiconductors requires ultrashallow, highly activated, abrupt dopant profiles in the source/drain extension regions, for technology nodes beyond 45 nm. The authors contrast B and BF_2 implants in Si and silicon on insulator (SOI) substrates with and without a preamorphizing implant (PAI). The objective of the study is to compare between Si and SOI substrates, PAI and non-PAI condition, and B and BF_2 implants. The results show the absence of the "reverse annealing effect" in BF_2 implants, which is observed in B implants. The presence of F appears to impede the formation of boron interstitial clusters, which is shown in the case of B implant. The BF_2 implants follow a similar trend for SOI and Si with and without PAI.