Hot-carrier-induced degradation of N/sub 2/O-oxynitrided gate oxide NMOSFETs

Abstract

Measurement of long term electrical characteristics of N/sub 2/O-oxynitrided gate oxide NMOSFETs revealed that the role of the nitrogen-rich layer as a blocking barrier for molecular hydrogen diffusion is dominant in the reduced device degradation. A two-step model was proposed, in which the release of hydrogen species and their reaction with the trivalent silicon atoms are the main factors for hot-carrier-induced-degradation. Hot carrier immunity of the NMOSFETs was also found to originate partially from the small increase of both the effective barrier height for electron injection and the interface trap creation energy due to the negatively charged nitrogen-rich layer.