Stress induced leakage currents in N-MOSFETs submitted to channel hot carrier injections

In this study, we report on the electrical properties of the stress induced leakage current which appears through a 4.7 nm-thick SiO2 gate oxide of N-channel metal-oxide-semiconductor field effect transistors after localized channel hot carrier injections and Fowler-Nordheim uniform injections. We show that channel hot hole injections are able to induce a stress leakage current leading at longer times to a gate current versus gate voltage similar to the one obtained after uniform injections in the Fowler-Nordheim mode, and well fitted by a Schottky law. However, the kinetics of both degradation modes differ. Other localized hot carrier injection modes (channel hot electron injections) appear to be less efficient in producing stress induced leakage current. Hole injection at the Si/SiO2 interface, present in both channel hole injections and negative gate voltage Fowler-Nordheim stresses via the anode hole injection mechanism, is found to be the key phenomenon leading to stress induced leakage current generation. (C) 1999 Elsevier Science B.V. All rights reserved.