Improvement in hot carrier lifetime as a function of N/sub 2/ ion implantation before gate oxide growth in deep submicron NMOS devices

A detailed study of the impact of N/sub 2/ ion implantation (I/I) dose before gate oxide growth to hot carrier (HC) reliability of NMOSFETs is reported here, Improvements of more than 20/spl times/ in HC lifetime were achieved by the introduction of sufficiently high N/sub 2/ (I/I) doses. It was found that for NMOSFETs, the HC degradation correlates inversely to the initial interface state density introduced by the N/sub 2/ I/I process. This process-driven HC lifetime improvement does not require extensive post-metal anneals for HC lifetime improvements in advanced CMOS multilevel metal-dielectric processes.