Enhanced short-channel effects in NMOSFETs due to boron redistribution induced by arsenic source and drain implant

Abstract

The experimentally observed VT roll-off and Drain Induced Barrier Lowering (DIBL) at channel lengths of approximately=0.2 μ m in Si-MOSFETs is underestimated by conventional 2D numerical simulations. In this paper it is shown that this is due to B segregation from the channel region towards the As-implanted source/drain regions during the As activation anneal. The resulting B depletion close to the source and drain lowers the local VT and contributes significantly (up to 50% in 0.2 μ m n-channel MOSFETs) to the VT roll-off and DIBL in sub-quarter micron NMOSFETs. This B redistribution originates mainly from ion implantation damage in the source and drain.