Suppression of reverse short channel effect by nitrogenimplantation and its implications on nitrogen as a dopant species forapplications in 0.25 μm technology

摘要

Nitrogen implantation into the channel region was used for thereduction of the “Reverse Short Channel Effect(RSCE)”. Thisapproach was found to be very effective in reducing the RSCE withoutadverse effects on the short channel behavior. The reduction of the RSCEis believed to be due to the implanted nitrogen ions. These implantednitrogen ions retards the redistribution of the channel boronconcentration, which is believed to be the cause of the RSCE. Thresholdvoltage shifts were observed in both n- and p-ch MOSFETs. We proposethat these threshold voltage shifts are due to the partial activation ofthe nitrogen atoms that have taken up substitutional sites in thesilicon lattice and thus behave as a dopant species for silicon