Role of hot-hole injection in hot-carrier effects and the small degraded channel region in MOSFET's

Abstract

Drain avalanche hot-carrier (DAHC) injection, which imposes the most severe limitations on n-channel MOS device design, is investigated from the viewpoint of surface-state generation and its localized area in the channel. It is shown, using the charge pumping technique, that the surface states are mainly created by hot-hole injection, and its small degraded area stretches toward the source region with increased stress time. A remarkable correlation between the increase of surface-state density, transconductance degradation, and substrate current is also described. In addition, to clarify the role of hot-hole injection, p-channel devices, as well as n-channel devices, are used, and hot-hole injection is shown to create more surface states than hot-electron injection.