Channel-width effect on hot-carrier degradation in NMOSFETs with recessed-LOCOS isolation structures

Abstract

Narrow-channel nMOSFETs with recessed LOCOS (R-LOCOS) isolation structure exhibits less hot-carrier-induced degradation than wide-channel nMOSFETs, but the degradation mechanism of both devices is the same. This new finding is explained by the fact that in deep submicrometer MOSFETs with ultra-thin gate oxides and a relatively thin field oxide, the dominant factor deciding the degradation behaviour in narrow channel and wide channel devices is the vertical electric field effect rather than the mechanical stress effect.