Role of N/sub 2/ ion implantation dose on hot carrier lifetime in deep submicron NMOS devices

Abstract

The impact of N/sub 2/ 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 N/sub 2/ (I/I) doses. It was found that for NMOSFET's the HC degradation correlates inversely to the initial interface state density introduced by the N/sub 2/ 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-SiO/sub 2/ interface with increasing N/sub 2/ dose.