Role of N2 ion implantation dose on hot carrier lifetime in deep submicron NMOS devices

The impact of N₂ ion implantation (I/I) dose before gate oxide growth on Hot Carrier (HC) reliability of NMOSFETs is reported here. Improvements ranging from 20 to 30 times in HC lifetime were achieved by the introduction of sufficiently high N₂ (I/I) doses. It was found that for NMOSFET´s the HC degradation correlates inversely to the initial interface state density introduced by the N₂ I/I process. We believe that the increased initial interface state density and the reduced hot carrier degradation both stem from the reduced hydrogen concentration at the Si-SiO₂ interface with increasing N₂ dose