Impact of Profiled LDD Structure on Hot Carrier Degradation of nMOSFET´s

The device degradation of profiled LDD nMOSFET due to hot-carrier is studied in detail. It was found that the major degradation mechanism of an LDD type of device was spacer-induced degradation. We proposed the profiled LDD structures which exhibited improvement in lifetime under high field stress. The impoved lifetime correlates with increased depth of peak avalanche region below the Si-SiO2 interface, and thus minimizing hot-carrier generation which is determined by the 2-dimensional device simulator MEDICI. Moreover, by using the additional arsenic implant just after phosphorous LDD implant, spacer-induced hot-carrier degradation was effectively suppressed without deteriorating the short channel effects.