Injection mechanisms and lifetime prediction with the substrate voltage in0.15 mu m channel-length N-MOSFETs

The effects of the substrate voltage are studied in advanced N-MOSFETs with a 3.2nm gate-oxide thickness used for logic applications. Results show tha t the electronic gate current originate at low voltage from tunneling contr ibutions and from the first-induced second impact ionization mechanisms. Th e injection efficiency is found to be channel-length dependent through a la rge increase in the gate-current with the increase in the lateral field (ve rtical field) and the electron-electron scattering for low energy hot-carri ers. Lifetime prediction techniques are compared showing a strong device li fetime reduction with the back bias at V-SB= V-DD independently of the extr apolating model which can be modeled by the measurement of the gate-current and the emission probability. (C) 2001 Elsevier Science Ltd. All rights re served.